diff --git a/AlgebraicDataflowArchitectureModel/models/Audio.dtram b/AlgebraicDataflowArchitectureModel/models/Audio.dtram
new file mode 100644
index 0000000..66862ef
--- /dev/null
+++ b/AlgebraicDataflowArchitectureModel/models/Audio.dtram
@@ -0,0 +1,33 @@
+model {
+channel CIO3 {
+	out BGMVolume(b: Double, setBGM(b2)) == b2
+}
+channel CIO2 {
+	out soundVolume(s: Double, setSound(s2)) == s2
+}
+channel CIO1 {
+	out audioVolume(a: Double, setAudio(a2)) == a2
+}
+channel C1 {
+	in audioVolume(a, calc(a2, s2)) == a2
+	in soundVolume(s, calc(a2, s2)) == s2
+	out outputSoundVolume(os, calc(a2, s2)) == a2 * s2
+}
+channel C2 {
+	in audioVolume(a, calc(a2, b2)) == a2
+	in BGMVolume(b, calc(a2, b2)) == b2
+	out outputBGMVolume(ob, calc(a2, b2)) == a2 * b2
+}
+}
+geometry {
+	node r soundVolume:220,140,80,30
+	node r audioVolume:220,280,80,30
+	node r outputSoundVolume:650,190,80,30
+	node r BGMVolume:220,420,80,30
+	node r outputBGMVolume:650,340,80,30
+	node ioc CIO3:100,420,30,30
+	node ioc CIO2:100,140,30,30
+	node ioc CIO1:100,280,30,30
+	node c C1:530,190,30,30
+	node c C2:530,340,30,30
+}
diff --git a/AlgebraicDataflowArchitectureModel/models/Clock.dtram b/AlgebraicDataflowArchitectureModel/models/Clock.dtram
index f619eaf..ae2169e 100644
--- a/AlgebraicDataflowArchitectureModel/models/Clock.dtram
+++ b/AlgebraicDataflowArchitectureModel/models/Clock.dtram
@@ -1,27 +1,27 @@
 model {
-channel CIO1 {
-   out min(m: Int, tick) == mod(m + 1, 60)
-}
-channel HourUpdate {
-   in hour(h: Int, update(h2)) == h2
-   out hour_hand(h_ang: Float, update(h2)) == h2 / 6 * PI
-}
-channel MinUpdate {
-   in min(m, update(m2)) == m2
-   out min_hand(m_ang: Float, update(m2)) == m2 / 30 * PI
-}
-channel Clock {
-   in min(m, update(m2)) == m2
-   out hour(h, update(m2)) == if(eq(m2, 0), mod(h + 1, 24), h)
-}
+	channel CIO1 {
+	   out min(m: Double, tick) == mod(m + 1, 60)
+	}
+	channel Clock {
+	   in min(m, update(m2)) == m2
+	   out hour(h: Double, update(m2)) == if(eq(m2, 0), mod(h + 1, 24), h)
+	}
+	channel MinUpdate {
+	   in min(m, update(m2)) == m2
+	   out min_ang(m_ang: Double, update(m2)) == m2 / 30 * PI
+	}
+	channel HourUpdate {
+	   in hour(h, update(h2)) == h2
+	   out hour_ang(h_ang: Double, update(h2)) == h2 / 6 * PI
+	}
 }
 geometry {
     node c HourUpdate:520,340,30,30
     node c MinUpdate:520,100,30,30
     node c Clock:280,220,30,30
-    node r min_hand:670,100,80,30
+    node r min_ang:670,100,80,30
     node r min:250,100,80,30
     node r hour:270,340,80,30
-    node r hour_hand:680,340,80,30
+    node r hour_ang:680,340,80,30
     node ioc CIO1:100,100,30,30
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/TypeInference.java b/AlgebraicDataflowArchitectureModel/src/algorithms/TypeInference.java
index d29070d..a18b3c1 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/TypeInference.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/TypeInference.java
@@ -13,6 +13,7 @@
 import javax.xml.crypto.Data;
 
 import models.Node;
+import models.algebra.Constant;
 import models.algebra.Expression;
 import models.algebra.Position;
 import models.algebra.Symbol;
@@ -22,6 +23,7 @@
 import models.dataConstraintModel.Channel;
 import models.dataConstraintModel.ChannelMember;
 import models.dataConstraintModel.DataConstraintModel;
+import models.dataConstraintModel.JsonType;
 import models.dataConstraintModel.ResourcePath;
 import models.dataConstraintModel.StateTransition;
 import models.dataFlowModel.DataTransferModel;
@@ -42,6 +44,8 @@
 	static private Map<Type, Type> pairComponentTypes = new HashMap<>();
 	static private Map<List<Type>, Type> mapTypes = new HashMap<>();
 	static private Map<Type, List<Type>> mapComponentTypes = new HashMap<>();
+	static private Map<Map<String, Type>, Type> jsonTypes = new HashMap<>();
+	static private Map<Type, Map<String, Type>> jsonMemberTypes = new HashMap<>();
 
 	public static Type getListType(Type compType) {
 		return listTypes.get(compType);
@@ -83,6 +87,14 @@
 		return mapComponentTypes.get(mapType);
 	}
 
+	public static Type getJsonType(Map<String, Type> memberTypes) {
+		return jsonTypes.get(memberTypes);
+	}
+
+	public static Map<String, Type> getJsonMemberTypes(Type jsonType) {
+		return jsonMemberTypes.get(jsonType);
+	}
+
 	static public void infer(DataTransferModel model) {
 		Map<ResourcePath, List<Expression>> resources = new HashMap<>();
 		Map<Integer, Type> variables = new HashMap<>();
@@ -91,6 +103,9 @@
 		Map<Integer, Type> tuple = new HashMap<>();
 		Map<Integer, Type> pair = new HashMap<>();
 		Map<Integer, Type> map = new HashMap<>();
+		Map<Integer, Type> json = new HashMap<>();
+		
+		// Maps from the objectId of each expression to its belonging group that has the same type as the expression
 		Map<Integer, List<Expression>> expToResource = new HashMap<>();
 		Map<Integer, List<Expression>> expToVariable = new HashMap<>();
 		Map<Integer, List<Expression>> expToMessage = new HashMap<>();
@@ -98,7 +113,9 @@
 		Map<Integer, Set<List<Expression>>> expToTuple = new HashMap<>();
 		Map<Integer, Set<List<Expression>>> expToPair = new HashMap<>();
 		Map<Integer, Set<List<Expression>>> expToMap = new HashMap<>();
+		Map<Integer, Set<List<Expression>>> expToJson = new HashMap<>();
 
+		// Maps from the objectId of each group to the set of updated expressions.
 		Map<Integer, Map<Integer, Expression>> updateFromResource = new HashMap<>();
 		Map<Integer, Map<Integer, Expression>> updateFromVariable = new HashMap<>();
 		Map<Integer, Map<Integer, Expression>> updateFromMessage = new HashMap<>();
@@ -106,6 +123,7 @@
 		Map<Integer, Map<Integer, Expression>> updateFromTuple = new HashMap<>();
 		Map<Integer, Map<Integer, Expression>> updateFromPair = new HashMap<>();
 		Map<Integer, Map<Integer, Expression>> updateFromMap = new HashMap<>();
+		Map<Integer, Map<Integer, Expression>> updateFromJson = new HashMap<>();
 
 		listComponentTypes.put(DataConstraintModel.typeList, null);
 		listComponentTypes.put(DataConstraintModel.typeListInt, DataConstraintModel.typeInt);
@@ -128,24 +146,24 @@
 		for (Channel c : channels) {
 			for (ChannelMember cm : c.getChannelMembers()) {
 				StateTransition st = cm.getStateTransition();
-				ResourcePath id = cm.getResource();
+				ResourcePath res = cm.getResource();
 				
 				// 1.1 Group expressions by resources.
-				List<Expression> sameResource = resources.get(id);
+				List<Expression> sameResource = resources.get(res);
 				if (sameResource == null) {
 					sameResource = new ArrayList<>();
-					resources.put(id, sameResource);
+					resources.put(res, sameResource);
 				}
 				sameResource.add(st.getCurStateExpression());
 				if (st.getNextStateExpression() != null) sameResource.add(st.getNextStateExpression());
 				expToResource.put(System.identityHashCode(st.getCurStateExpression()), sameResource);
 				if (st.getNextStateExpression() != null) expToResource.put(System.identityHashCode(st.getNextStateExpression()), sameResource);
 				Map<Integer, Expression> updatedExps = getUpdateSet(updateFromResource, sameResource);
-				Type resType = id.getResourceStateType();
+				Type resType = res.getResourceStateType();
 				Expression exp = st.getCurStateExpression();
 				Type expType = getExpTypeIfUpdatable(resType, exp);
 				if (expType != null) {
-					id.setResourceStateType(expType);
+					res.setResourceStateType(expType);
 					for (Expression resExp : sameResource) {
 						if (resExp != exp) {
 							if (resExp instanceof Variable && compareTypes(((Variable) resExp).getType(), expType)) {
@@ -168,12 +186,12 @@
 						updatedExps.put(System.identityHashCode(exp), exp);
 					}
 				}
-				resType = id.getResourceStateType();
+				resType = res.getResourceStateType();
 				exp = st.getNextStateExpression();
 				if (exp != null) {
 					expType = getExpTypeIfUpdatable(resType, exp);
 					if (expType != null) {
-						id.setResourceStateType(expType);
+						res.setResourceStateType(expType);
 						for (Expression resExp : sameResource) {
 							if (resExp != exp) {
 								if (resExp instanceof Variable && compareTypes(((Variable) resExp).getType(), expType)) {
@@ -343,7 +361,7 @@
 					if (symbol.equals(DataConstraintModel.cons) || symbol.equals(DataConstraintModel.set)) {
 						// If the root symbol of the term is cons or set.
 						List<Expression> consExps = new ArrayList<>();
-						consExps.add(t);
+						consExps.add(t);	// list term
 						updateExpressionBelonging(expToConsOrSet, t, consExps);
 						if (symbol.equals(DataConstraintModel.cons)) {
 							// If the root symbol of the term is cons.
@@ -354,10 +372,10 @@
 						} else {
 							// If the root symbol of the term is set.
 							Expression e = t.getChildren().get(2);
-							consExps.add(e);
+							consExps.add(e);	// list component
 							updateExpressionBelonging(expToConsOrSet, e, consExps);
 							e = t.getChildren().get(0);
-							consExps.add(e);
+							consExps.add(e);	// list argument
 							updateExpressionBelonging(expToConsOrSet, e, consExps);							
 						}
 						Type newType = getExpTypeIfUpdatable(t.getType(), consExps.get(2));
@@ -410,9 +428,9 @@
 						// If the root symbol of the term is head or get.
 						List<Expression> consExps = new ArrayList<>();
 						Expression e = t.getChildren().get(0);
-						consExps.add(e);
+						consExps.add(e);		// list argument
 						updateExpressionBelonging(expToConsOrSet, e, consExps);
-						consExps.add(t);
+						consExps.add(t);		// list's component
 						updateExpressionBelonging(expToConsOrSet, t, consExps);
 						consExps.add(null);
 						Type listType = listTypes.get(t.getType());
@@ -446,11 +464,11 @@
 					} else if (symbol.equals(DataConstraintModel.tail)) {
 						// If the root symbol of the term is tail.
 						List<Expression> consExps = new ArrayList<>();
-						consExps.add(t);
+						consExps.add(t);		// list term
 						updateExpressionBelonging(expToConsOrSet, t, consExps);
-						consExps.add(null);
+						consExps.add(null);		// list's component
 						Expression e = t.getChildren().get(0);
-						consExps.add(e);
+						consExps.add(e);		// list argument
 						updateExpressionBelonging(expToConsOrSet, e, consExps);							
 						Type newType = getExpTypeIfUpdatable(t.getType(), consExps.get(2));
 						if (newType != null) {
@@ -482,26 +500,27 @@
 					} else if (symbol.equals(DataConstraintModel.tuple)) {
 						// If the root symbol of the term is tuple.
 						List<Expression> tupleExps = new ArrayList<>();
-						List<Type> argsTypeList = new ArrayList<>();
-						tupleExps.add(t);
+						List<Type> newArgTypesList = new ArrayList<>();
+						tupleExps.add(t);	// tuple term
 						updateExpressionBelonging(expToTuple, t, tupleExps);
 						for (Expression e : t.getChildren()) {
-							tupleExps.add(e);
+							tupleExps.add(e);	// tuple's component
 							updateExpressionBelonging(expToTuple, e, tupleExps);
 							if (e instanceof Variable) {
-								argsTypeList.add(((Variable) e).getType());
+								newArgTypesList.add(((Variable) e).getType());
 							} else if (e instanceof Term) {
-								argsTypeList.add(((Term) e).getType());
+								newArgTypesList.add(((Term) e).getType());
 							} else {
-								argsTypeList.add(null);
+								newArgTypesList.add(null);
 							}
 						}
 						if (t.getType() == DataConstraintModel.typeTuple) {
-							Type newTupleType = tupleTypes.get(argsTypeList);
+							Type newTupleType = tupleTypes.get(newArgTypesList);
 							if (newTupleType == null) {
 								// Create new tuple type;
-								newTupleType = createNewTupleType(argsTypeList, DataConstraintModel.typeTuple);
+								newTupleType = createNewTupleType(newArgTypesList, DataConstraintModel.typeTuple);
 							}
+							// Update the type of the tuple term and record the updated expression.
 							t.setType(newTupleType);
 							Map<Integer, Expression> updateExps = getUpdateSet(updateFromTuple, tupleExps);
 							updateExps.put(System.identityHashCode(t), t);
@@ -510,22 +529,22 @@
 					} else if (symbol.equals(DataConstraintModel.pair)) {
 						// If the root symbol of the term is pair.
 						List<Expression> pairExps = new ArrayList<>();
-						pairExps.add(t);
+						pairExps.add(t);		// pair
 						updateExpressionBelonging(expToPair, t, pairExps);
 						if (t.getType() == DataConstraintModel.typePair) {
 							for (Expression e : t.getChildren()) {
-								pairExps.add(e);
+								pairExps.add(e);	// left/right
 								updateExpressionBelonging(expToPair, e, pairExps);
-								Type argType = null;
+								Type newArgType = null;
 								if (e instanceof Variable) {
-									argType = (((Variable) e).getType());
+									newArgType = (((Variable) e).getType());
 									
 								} else if (e instanceof Term) {
-									argType = (((Term) e).getType());
+									newArgType = (((Term) e).getType());
 								}
 								
-								if (argType != null) {
-									Type newPairType = pairTypes.get(argType);
+								if (newArgType != null) {
+									Type newPairType = pairTypes.get(newArgType);
 									if (newPairType != null) {
 										t.setType(newPairType);
 										Map<Integer, Expression> updateExps = getUpdateSet(updateFromPair, pairExps);
@@ -540,11 +559,11 @@
 						// If the root symbol of the term is fst.
 						List<Expression> tupleExps = new ArrayList<>();
 						Expression arg = t.getChildren().get(0);
-						tupleExps.add(arg);
+						tupleExps.add(arg);		// tuple argument
 						updateExpressionBelonging(expToTuple, arg, tupleExps);
-						tupleExps.add(t);
+						tupleExps.add(t);		// first component
 						updateExpressionBelonging(expToTuple, t, tupleExps);
-						tupleExps.add(null);
+						tupleExps.add(null);	// second component
 						Type argType = null;
 						if (arg instanceof Variable) {
 							argType = ((Variable) arg).getType();
@@ -553,16 +572,17 @@
 						}
 						Type newTupleType = DataConstraintModel.typeTuple;
 						if (argType == DataConstraintModel.typeTuple && t.getType() != null) {
-							List<Type> compTypeList = new ArrayList<>();
-							compTypeList.add(t.getType());
-							compTypeList.add(null);
-							newTupleType = tupleTypes.get(compTypeList);
+							List<Type> newCompTypeList = new ArrayList<>();
+							newCompTypeList.add(t.getType());
+							newCompTypeList.add(null);
+							newTupleType = tupleTypes.get(newCompTypeList);
 							if (newTupleType == null) {
 								// Create new tuple type;
-								newTupleType = createNewTupleType(compTypeList, DataConstraintModel.typeTuple);
+								newTupleType = createNewTupleType(newCompTypeList, DataConstraintModel.typeTuple);
 							}
 						}
 						if (argType != newTupleType && newTupleType != null) {
+							// Update the type of the tuple argument and record the updated expression.
 							if (arg instanceof Variable) {
 								((Variable) arg).setType(newTupleType);
 								argType = newTupleType;
@@ -578,10 +598,10 @@
 						// If the root symbol of the term is snd.
 						List<Expression> tupleExps = new ArrayList<>();
 						Expression arg = t.getChildren().get(0);
-						tupleExps.add(arg);
+						tupleExps.add(arg);		// tuple argument
 						updateExpressionBelonging(expToTuple, arg, tupleExps);
-						tupleExps.add(null);
-						tupleExps.add(t);
+						tupleExps.add(null);	// first component
+						tupleExps.add(t);		// second component
 						updateExpressionBelonging(expToTuple, t, tupleExps);
 						Type argType = null;
 						if (arg instanceof Variable) {
@@ -591,27 +611,28 @@
 						}
 						Type newTupleType = DataConstraintModel.typeTuple;
 						if (argType == DataConstraintModel.typeTuple && t.getType() != null) {
-							List<Type> compTypeList = new ArrayList<>();
-							compTypeList.add(null);
+							List<Type> newCompTypeList = new ArrayList<>();
+							newCompTypeList.add(null);
 							if (DataConstraintModel.typeTuple.isAncestorOf(t.getType())) {
 								List<Type> sndTypes = tupleComponentTypes.get(t.getType());
 								if (sndTypes != null) {
 									for (Type t2: sndTypes) {
-										compTypeList.add(t2);
+										newCompTypeList.add(t2);
 									}
 								} else {
-									compTypeList.add(t.getType());
+									newCompTypeList.add(t.getType());
 								}
 							} else {
-								compTypeList.add(t.getType());
+								newCompTypeList.add(t.getType());
 							}
-							newTupleType = tupleTypes.get(compTypeList);
+							newTupleType = tupleTypes.get(newCompTypeList);
 							if (newTupleType == null) {
 								// Create new tuple type;
-								newTupleType = createNewTupleType(compTypeList, DataConstraintModel.typeTuple);
+								newTupleType = createNewTupleType(newCompTypeList, DataConstraintModel.typeTuple);
 							}
 						}
 						if (argType != newTupleType && newTupleType != null) {
+							// Update the type of the tuple argument and record the updated expression.
 							if (arg instanceof Variable) {
 								((Variable) arg).setType(newTupleType);
 								argType = newTupleType;
@@ -627,11 +648,11 @@
 						// If the root symbol of the term is left.
 						List<Expression> pairExps = new ArrayList<>();
 						Expression arg = t.getChildren().get(0);
-						pairExps.add(arg);
+						pairExps.add(arg);		// pair
 						updateExpressionBelonging(expToPair, arg, pairExps);
-						pairExps.add(t);
+						pairExps.add(t);		// left
 						updateExpressionBelonging(expToPair, t, pairExps);
-						pairExps.add(null);
+						pairExps.add(null);		// right
 						Type argType = null;
 						if (arg instanceof Variable) {
 							argType = ((Variable) arg).getType();
@@ -640,13 +661,13 @@
 						}
 						Type newPairType = DataConstraintModel.typePair;
 						if (argType == DataConstraintModel.typePair && t.getType() != null) {
-							List<Type> compTypeList = new ArrayList<>();
-							compTypeList.add(t.getType());
-							compTypeList.add(null);
-							newPairType = pairTypes.get(compTypeList);
+							List<Type> newCompTypeList = new ArrayList<>();
+							newCompTypeList.add(t.getType());
+							newCompTypeList.add(null);
+							newPairType = pairTypes.get(newCompTypeList);
 							if (newPairType == null) {
 								// Create new tuple type;
-								newPairType = createNewTupleType(compTypeList, DataConstraintModel.typePair);
+								newPairType = createNewTupleType(newCompTypeList, DataConstraintModel.typePair);
 							}
 						}
 						if (argType != newPairType && newPairType != null) {
@@ -665,10 +686,10 @@
 						// If the root symbol of the term is right.
 						List<Expression> pairExps = new ArrayList<>();
 						Expression arg = t.getChildren().get(0);
-						pairExps.add(arg);
+						pairExps.add(arg);		// pair
 						updateExpressionBelonging(expToPair, arg, pairExps);
-						pairExps.add(null);
-						pairExps.add(t);
+						pairExps.add(null);		// left
+						pairExps.add(t);		// right
 						updateExpressionBelonging(expToPair, t, pairExps);
 						Type argType = null;
 						if (arg instanceof Variable) {
@@ -678,13 +699,13 @@
 						}
 						Type newPairType = DataConstraintModel.typePair;
 						if (argType == DataConstraintModel.typePair && t.getType() != null) {
-							List<Type> compTypeList = new ArrayList<>();
-							compTypeList.add(null);
-							compTypeList.add(t.getType());
-							newPairType = pairTypes.get(compTypeList);
+							List<Type> newCompTypeList = new ArrayList<>();
+							newCompTypeList.add(null);
+							newCompTypeList.add(t.getType());
+							newPairType = pairTypes.get(newCompTypeList);
 							if (newPairType == null) {
 								// Create new tuple type;
-								newPairType = createNewTupleType(compTypeList, DataConstraintModel.typePair);
+								newPairType = createNewTupleType(newCompTypeList, DataConstraintModel.typePair);
 							}
 						}
 						if (argType != newPairType && newPairType != null) {
@@ -716,21 +737,22 @@
 						} else if (arg1 instanceof Term) {
 							arg1Type = ((Term) arg1).getType();
 						}
-						List<Type> compTypeList = new ArrayList<>();
+						List<Type> newCompTypeList = new ArrayList<>();
 						if (arg2 instanceof Variable) {
-							compTypeList.add(((Variable) arg2).getType());
+							newCompTypeList.add(((Variable) arg2).getType());
 						} else if (arg2 instanceof Term) {
-							compTypeList.add(((Term) arg2).getType());
+							newCompTypeList.add(((Term) arg2).getType());
 						} else {
-							compTypeList.add(null);
+							newCompTypeList.add(null);
 						}
-						compTypeList.add(t.getType());
+						newCompTypeList.add(t.getType());
 						if (arg1Type == DataConstraintModel.typeMap || arg1Type == null) {
-							Type newMapType = mapTypes.get(compTypeList);
+							Type newMapType = mapTypes.get(newCompTypeList);
 							if (newMapType == null) {
 								// Create new tuple type;
-								newMapType = createNewMapType(compTypeList, DataConstraintModel.typeMap);
+								newMapType = createNewMapType(newCompTypeList, DataConstraintModel.typeMap);
 							}
+							// Update the type of the map argument and record the updated expression.
 							if (arg1 instanceof Variable) {
 								((Variable) arg1).setType(newMapType);
 								arg1Type = newMapType;
@@ -757,33 +779,186 @@
 						mapExps.add(arg0);
 						updateExpressionBelonging(expToMap, arg0, mapExps);
 						Type termType = t.getType();
-						List<Type> compTypeList = new ArrayList<>();
+						List<Type> newCompTypeList = new ArrayList<>();
 						if (arg1 instanceof Variable) {
-							compTypeList.add(((Variable) arg1).getType());
+							newCompTypeList.add(((Variable) arg1).getType());
 						} else if (arg1 instanceof Term) {
-							compTypeList.add(((Term) arg1).getType());
+							newCompTypeList.add(((Term) arg1).getType());
 						} else {
-							compTypeList.add(null);
+							newCompTypeList.add(null);
 						}
 						if (arg2 instanceof Variable) {
-							compTypeList.add(((Variable) arg2).getType());
+							newCompTypeList.add(((Variable) arg2).getType());
 						} else if (arg2 instanceof Term) {
-							compTypeList.add(((Term) arg2).getType());
+							newCompTypeList.add(((Term) arg2).getType());
 						} else {
-							compTypeList.add(null);
+							newCompTypeList.add(null);
 						}
 						if (termType == DataConstraintModel.typeMap || termType == null) {
-							Type newMapType = mapTypes.get(compTypeList);
+							Type newMapType = mapTypes.get(newCompTypeList);
 							if (newMapType == null) {
 								// Create new tuple type;
-								newMapType = createNewMapType(compTypeList, DataConstraintModel.typeMap);
+								newMapType = createNewMapType(newCompTypeList, DataConstraintModel.typeMap);
 							}
+							// Update the type of the map term and record the updated expression.
 							t.setType(newMapType);
 							termType = newMapType;
 							Map<Integer, Expression> updateExps = getUpdateSet(updateFromMap, mapExps);
 							updateExps.put(System.identityHashCode(t), t);
 						}
 						map.put(System.identityHashCode(mapExps), termType);
+					} else if (symbol.equals(DataConstraintModel.addMember)) {
+						// If the root symbol of the term is addMember (addMember(json, key, value)).
+						List<Expression> dotExps = new ArrayList<>();
+						Expression jsonArg = t.getChildren().get(0);
+						Expression keyArg = t.getChildren().get(1);
+						Expression valueArg = t.getChildren().get(2);
+						dotExps.add(t);			// json
+						updateExpressionBelonging(expToJson, t, dotExps);
+						dotExps.add(keyArg);	// key
+						updateExpressionBelonging(expToJson, keyArg, dotExps);
+						dotExps.add(valueArg);	// value
+						updateExpressionBelonging(expToJson, valueArg, dotExps);
+						dotExps.add(jsonArg);	// json
+						updateExpressionBelonging(expToJson, jsonArg, dotExps);
+						Type jsonType = t.getType();
+						Type valueType = null;
+						if (valueArg instanceof Variable) {
+							valueType = ((Variable) valueArg).getType();
+						} else if (valueArg instanceof Term) {
+							valueType = ((Term) valueArg).getType();
+						}
+						String keyName = null;
+						if (keyArg instanceof Constant) {
+							keyName = ((Constant) keyArg).getSymbol().getName();
+						}
+						Type jsonArgType = null;
+						if (jsonArg instanceof Variable) {
+							jsonArgType = ((Variable) jsonArg).getType();
+						} else if (jsonArg instanceof Term) {
+							jsonArgType = ((Term) jsonArg).getType();
+						}
+						Type newJsonType = DataConstraintModel.typeJson;
+						if (jsonType == DataConstraintModel.typeJson && jsonArgType != null && keyName != null) {
+							Map<String, Type> newMemberTypes = new HashMap<>(((JsonType) jsonArgType).getMemberTypes());
+							newMemberTypes.put(keyName, valueType);
+							newJsonType = jsonTypes.get(newMemberTypes);
+							if (newJsonType == null) {
+								// Create new json type;
+								newJsonType = createNewJsonType(newMemberTypes, DataConstraintModel.typeJson);
+							}
+						}
+						if (jsonType != newJsonType && newJsonType != null) {
+							// Update the type of the json term and record the updated expression.
+							t.setType(newJsonType);
+							jsonType = newJsonType;
+							Map<Integer, Expression> updateExps = getUpdateSet(updateFromJson, dotExps);
+							updateExps.put(System.identityHashCode(t), t);
+						}
+						json.put(System.identityHashCode(dotExps), jsonType);
+					} else if (symbol.equals(DataConstraintModel.dot)) {
+						// If the root symbol of the term is dot (json.property).
+						List<Expression> dotExps = new ArrayList<>();
+						Expression jsonArg = t.getChildren().get(0);
+						Expression keyArg = t.getChildren().get(1);
+						dotExps.add(jsonArg);	// json
+						updateExpressionBelonging(expToJson, jsonArg, dotExps);
+						dotExps.add(keyArg);	// key
+						updateExpressionBelonging(expToJson, keyArg, dotExps);
+						dotExps.add(t);			// value
+						updateExpressionBelonging(expToJson, t, dotExps);
+						dotExps.add(null);		// json
+						Type jsonType = null;
+						if (jsonArg instanceof Variable) {
+							jsonType = ((Variable) jsonArg).getType();
+						} else if (jsonArg instanceof Term) {
+							jsonType = ((Term) jsonArg).getType();
+						}
+						String keyName = null;
+						if (keyArg instanceof Constant) {
+							keyName = ((Constant) keyArg).getSymbol().getName();
+						}
+						Type newJsonType = DataConstraintModel.typeJson;
+						if (jsonType == DataConstraintModel.typeJson && t.getType() != null && keyName != null) {
+							Map<String, Type> newMemberTypes = new HashMap<>();
+							newMemberTypes.put(keyName, t.getType());
+							newJsonType = jsonTypes.get(newMemberTypes);
+							if (newJsonType == null) {
+								// Create new json type;
+								newJsonType = createNewJsonType(newMemberTypes, DataConstraintModel.typeJson);
+							}
+						}
+						if (jsonType != newJsonType && newJsonType != null) {
+							// Update the type of the json argument and record the updated expression.
+							if (jsonArg instanceof Variable) {
+								((Variable) jsonArg).setType(newJsonType);
+								jsonType = newJsonType;
+							} else if (jsonArg instanceof Term) {
+								((Term) jsonArg).setType(newJsonType);
+								jsonType = newJsonType;
+							}
+							Map<Integer, Expression> updateExps = getUpdateSet(updateFromJson, dotExps);
+							updateExps.put(System.identityHashCode(jsonArg), jsonArg);
+						}
+						json.put(System.identityHashCode(dotExps), jsonType);
+					} else if (symbol.equals(DataConstraintModel.dotParam)) {
+						// If the root symbol of the term is dot (json.{param}).
+						List<Expression> dotExps = new ArrayList<>();
+						Expression jsonArg = t.getChildren().get(0);
+						Expression keyArg = t.getChildren().get(1);
+						dotExps.add(jsonArg);	// json (list/map)
+						updateExpressionBelonging(expToJson, jsonArg, dotExps);
+						dotExps.add(null);		// key
+						dotExps.add(t);			// value
+						updateExpressionBelonging(expToJson, t, dotExps);
+						dotExps.add(null);		// json
+						Type jsonType = null;
+						if (jsonArg instanceof Variable) {
+							jsonType = ((Variable) jsonArg).getType();
+						} else if (jsonArg instanceof Term) {
+							jsonType = ((Term) jsonArg).getType();
+						}
+						Type keyType = null;
+						if (keyArg instanceof Variable) {
+							keyType = ((Variable) keyArg).getType();
+						} else if (keyArg instanceof Term) {
+							keyType = ((Term) keyArg).getType();
+						}
+						Type newJsonType = null;
+						if (keyType == DataConstraintModel.typeInt) {
+							newJsonType = DataConstraintModel.typeList;
+						} else if (keyType == DataConstraintModel.typeString) {
+							newJsonType = DataConstraintModel.typeMap;
+						}
+						if (t.getType() != null) {
+							if ((jsonType == DataConstraintModel.typeList)) {
+								newJsonType = listTypes.get(t.getType());
+								if (newJsonType == null) {
+									// Create new list type;
+									newJsonType = createNewListType(t.getType(), DataConstraintModel.typeList);
+								}
+							} else if (jsonType == DataConstraintModel.typeMap) {
+								List<Type> keyValueTypes = Arrays.asList(new Type[] {DataConstraintModel.typeString, t.getType()});
+								newJsonType = mapTypes.get(keyValueTypes);
+								if (newJsonType == null) {
+									// Create new map type;
+									newJsonType = createNewMapType(keyValueTypes, DataConstraintModel.typeMap);
+								}
+							}
+						}
+						if (jsonType != newJsonType && newJsonType != null) {
+							// Update the type of the json argument and record the updated expression.
+							if (jsonArg instanceof Variable) {
+								((Variable) jsonArg).setType(newJsonType);
+								jsonType = newJsonType;
+							} else if (jsonArg instanceof Term) {
+								((Term) jsonArg).setType(newJsonType);
+								jsonType = newJsonType;
+							}
+							Map<Integer, Expression> updateExps = getUpdateSet(updateFromJson, dotExps);
+							updateExps.put(System.identityHashCode(jsonArg), jsonArg);
+						}
+						json.put(System.identityHashCode(dotExps), jsonType);
 					} else if (symbol.equals(DataConstraintModel.cond)) {
 						// If the root symbol of the term is if function.
 						Expression c1 = t.getChild(1);
@@ -929,7 +1104,8 @@
 		
 		// 2. Propagate type information.
 		while (updateFromResource.size() > 0 || updateFromVariable.size() > 0 || updateFromMessage.size() > 0
-				|| updateFromConsOrSet.size() > 0 || updateFromTuple.size() > 0 || updateFromPair.size() > 0 || updateFromMap.size() > 0) {
+				|| updateFromConsOrSet.size() > 0 || updateFromTuple.size() > 0 || updateFromPair.size() > 0 
+				|| updateFromMap.size() > 0 || updateFromJson.size() > 0) {
 			if (updateFromResource.size() > 0) {
 				Set<Integer> resourceKeys = updateFromResource.keySet();
 				Integer resourceKey = resourceKeys.iterator().next();
@@ -943,6 +1119,7 @@
 					updateTupleTypes(resExp, tuple, expToTuple, updateFromTuple);
 					updatePairTypes(resExp, pair, expToPair, updateFromPair);
 					updateMapTypes(resExp, map, expToMap, updateFromMap);
+					updateJsonTypes(resExp, json, expToJson, updateFromJson);
 				}
 			}
 			if (updateFromVariable.size() > 0) {
@@ -959,6 +1136,7 @@
 					updateTupleTypes(var, tuple, expToTuple, updateFromTuple);
 					updatePairTypes(var, pair, expToPair, updateFromPair);
 					updateMapTypes(var, map, expToMap, updateFromMap);
+					updateJsonTypes(var, json, expToJson, updateFromJson);
 				}
 			}
 			if (updateFromMessage.size() > 0) {
@@ -974,6 +1152,7 @@
 					updateTupleTypes(mesExp, tuple, expToTuple, updateFromTuple);
 					updatePairTypes(mesExp, pair, expToPair, updateFromPair);
 					updateMapTypes(mesExp, map, expToMap, updateFromMap);
+					updateJsonTypes(mesExp, json, expToJson, updateFromJson);
 				}
 			}
 			if (updateFromConsOrSet.size() > 0) {
@@ -990,6 +1169,7 @@
 					updateTupleTypes(consExp, tuple, expToTuple, updateFromTuple);
 					updatePairTypes(consExp, pair, expToPair, updateFromPair);
 					updateMapTypes(consExp, map, expToMap, updateFromMap);
+					updateJsonTypes(consExp, json, expToJson, updateFromJson);
 				}
 			}
 			if (updateFromTuple.size() > 0) {
@@ -1006,6 +1186,7 @@
 					updateTupleTypes(tupleExp, tuple, expToTuple, updateFromTuple);
 					updatePairTypes(tupleExp, pair, expToPair, updateFromPair);
 					updateMapTypes(tupleExp, map, expToMap, updateFromMap);
+					updateJsonTypes(tupleExp, json, expToJson, updateFromJson);
 				}
 			}
 			if (updateFromPair.size() > 0) {
@@ -1022,6 +1203,7 @@
 					updateTupleTypes(pairExp, tuple, expToTuple, updateFromTuple);
 					updatePairTypes(pairExp, pair, expToPair, updateFromPair);
 					updateMapTypes(pairExp, map, expToMap, updateFromMap);
+					updateJsonTypes(pairExp, json, expToJson, updateFromJson);
 				}
 			}
 			if (updateFromMap.size() > 0) {
@@ -1038,6 +1220,24 @@
 					updateTupleTypes(mapExp, tuple, expToTuple, updateFromTuple);
 					updatePairTypes(mapExp, pair, expToPair, updateFromPair);
 					updateMapTypes(mapExp, map, expToMap, updateFromMap);
+					updateJsonTypes(mapExp, json, expToJson, updateFromJson);
+				}
+			}
+			if (updateFromJson.size() > 0) {
+				Set<Integer> jsonKeys = updateFromJson.keySet();
+				Integer jsonKey = jsonKeys.iterator().next();
+				Map<Integer, Expression> jsonValue = updateFromJson.get(jsonKey);
+				updateFromJson.remove(jsonKey);
+				for (int i : jsonValue.keySet()) {
+					Expression jsonExp = jsonValue.get(i);
+					updateResourceTypes(jsonExp, resources, expToResource, updateFromResource);
+					updateVaribleTypes(jsonExp, variables, expToVariable, updateFromVariable);
+					updateMessageTypes(jsonExp, messages, expToMessage, updateFromMessage);
+					updateConsOrSetTypes(jsonExp, consOrSet, expToConsOrSet, updateFromConsOrSet);
+					updateTupleTypes(jsonExp, tuple, expToTuple, updateFromTuple);
+					updatePairTypes(jsonExp, pair, expToPair, updateFromPair);
+					updateMapTypes(jsonExp, map, expToMap, updateFromMap);
+					updateJsonTypes(jsonExp, json, expToJson, updateFromJson);
 				}
 			}
 		}
@@ -1060,12 +1260,12 @@
 			Map<Integer, List<Expression>> expToResource, Map<Integer, Map<Integer, Expression>> updateFromResource) {
 		List<Expression> sameResource = expToResource.get(System.identityHashCode(exp));
 		if (sameResource == null) return;
-		for (ResourcePath id : resources.keySet()) {
-			if (resources.get(id) == sameResource) {
-				Type resType = id.getResourceStateType();
+		for (ResourcePath res : resources.keySet()) {
+			if (resources.get(res) == sameResource) {
+				Type resType = res.getResourceStateType();
 				Type newResType = getExpTypeIfUpdatable(resType, exp);
 				if (newResType != null) {
-					id.setResourceStateType(newResType);
+					res.setResourceStateType(newResType);
 					Map<Integer, Expression> updateExps = getUpdateSet(updateFromResource, sameResource);
 					for (Expression resExp : sameResource) {
 						if (resExp != exp) {
@@ -1167,6 +1367,7 @@
 			int idx = consOrSetComponentGroup.indexOf(exp);
 			switch (idx) {
 			case 0:
+				// exp is a list itself.
 				if (!(exp instanceof Term)) break;
 				Type listType = consOrSet.get(System.identityHashCode(consOrSetComponentGroup));
 				Type expType = getExpTypeIfUpdatable(listType, exp);
@@ -1191,6 +1392,7 @@
 				}
 				break;
 			case 1:
+				// exp is a list's component.
 				listType = consOrSet.get(System.identityHashCode(consOrSetComponentGroup));
 				Type compType = listComponentTypes.get(listType);
 				Type newCompType = getExpTypeIfUpdatable(compType, exp);
@@ -1216,6 +1418,7 @@
 				}
 				break;
 			case 2:
+				// exp is a list itself.
 				listType = consOrSet.get(System.identityHashCode(consOrSetComponentGroup));
 				expType = getExpTypeIfUpdatable(listType, exp);
 				if (expType != null) {
@@ -1245,6 +1448,7 @@
 		for (List<Expression> tupleComponentGroup: tupleComponentGroups) {
 			int idx = tupleComponentGroup.indexOf(exp);
 			if (idx == 0) {
+				// exp is a tuple itself.
 				Type tupleType = tuple.get(System.identityHashCode(tupleComponentGroup));
 				Type newTupleType = getExpTypeIfUpdatable(tupleType, exp);
 				if (newTupleType != null) {
@@ -1312,6 +1516,7 @@
 					}
 				}
 			} else {
+				// exp is a tuple's component.
 				Type tupleType = tuple.get(System.identityHashCode(tupleComponentGroup));
 				List<Type> componentTypes = tupleComponentTypes.get(tupleType);
 				boolean updated = false;
@@ -1382,6 +1587,7 @@
 		for (List<Expression> pairComponentGroup: pairComponentGroups) {
 			int idx = pairComponentGroup.indexOf(exp);
 			if (idx == 0) {
+				// exp is a pair itself.
 				Type pairType = pair.get(System.identityHashCode(pairComponentGroup));
 				Type newPairType = getExpTypeIfUpdatable(pairType, exp);
 				if (newPairType != null) {
@@ -1405,6 +1611,7 @@
 					}
 				}
 			} else {
+				// exp is a pair's component.
 				Type pairType = pair.get(System.identityHashCode(pairComponentGroup));
 				Type compType = pairComponentTypes.get(pairType);
 				Type newCompType = getExpTypeIfUpdatable(compType, exp);
@@ -1435,6 +1642,7 @@
 		for (List<Expression> mapComponentGroup: mapComponentGroups) {
 			int idx = mapComponentGroup.indexOf(exp);
 			if (idx == 0 || idx == 3) {
+				// exp is a map itself.
 				Type mapType = map.get(System.identityHashCode(mapComponentGroup));
 				Type newMapType = getExpTypeIfUpdatable(mapType, exp);
 				if (newMapType != null) {
@@ -1478,6 +1686,7 @@
 					}
 				}
 			} else {
+				// exp is a map's key or value.
 				Type mapType = map.get(System.identityHashCode(mapComponentGroup));
 				List<Type> componentTypes = mapComponentTypes.get(mapType);
 				Type compType = componentTypes.get(idx - 1);
@@ -1516,6 +1725,116 @@
 		}
 	}
 	
+	
+	private static void updateJsonTypes(Expression exp, Map<Integer, Type> json,
+			Map<Integer, Set<List<Expression>>> expToJson, Map<Integer, Map<Integer, Expression>> updateFromJson) {
+		Set<List<Expression>> jsonMemberGroups = expToJson.get(System.identityHashCode(exp));
+		if (jsonMemberGroups == null) return;
+		for (List<Expression> jsonMemberGroup: jsonMemberGroups) {
+			int idx = jsonMemberGroup.indexOf(exp);
+			if (idx == 3) {
+				// exp is a json argument (0:t = addMember(3:json, 1:key, 2:value)).
+				Type jsonType = json.get(System.identityHashCode(jsonMemberGroup));
+				Map<String, Type> memberTypes = new HashMap<>(jsonMemberTypes.get(jsonType));
+				Map<String, Type> argMemberTypes = new HashMap<>(memberTypes);
+				String keyName = null;
+				Type valueType = null;
+				if (jsonMemberGroup.get(1) instanceof Constant) {
+					keyName = ((Constant) jsonMemberGroup.get(1)).getSymbol().getName();
+					valueType = ((Constant) jsonMemberGroup.get(1)).getType();
+					argMemberTypes.remove(keyName);
+				}
+				Type jsonArgType = jsonTypes.get(argMemberTypes);
+				Type newJsonArgType = getExpTypeIfUpdatable(jsonArgType, exp);
+				if (newJsonArgType != null && keyName != null) {
+					// Propagate an update of a json arg's type to its container's (json's) type.
+					argMemberTypes = ((JsonType) newJsonArgType).getMemberTypes();
+					argMemberTypes.put(keyName, valueType);
+					memberTypes.putAll(argMemberTypes);
+					Type newJsonType = jsonTypes.get(memberTypes);
+					if (newJsonType == null) {
+						// Create new json type.
+						newJsonType = createNewJsonType(memberTypes, jsonType);
+					}
+					// Update the type of the json term and record the updated expression.
+					Map<Integer, Expression> updateExps = getUpdateSet(updateFromJson, jsonMemberGroup);
+					Expression jsonExp = jsonMemberGroup.get(0);
+					if (jsonExp instanceof Variable) {
+						((Variable) jsonExp).setType(newJsonType);
+						updateExps.put(System.identityHashCode(jsonExp), jsonExp);
+					} else if (jsonExp instanceof Term) {
+						((Term) jsonExp).setType(newJsonType);
+						updateExps.put(System.identityHashCode(jsonExp), jsonExp);
+					}
+					json.put(System.identityHashCode(jsonMemberGroup), newJsonType);
+				}
+			} else if (idx == 2) {
+				// exp is a value (0:t = addMember(3:json, 1:key, 2:value) or 2:value = dot(0:list/map, 1:key)).
+				Type jsonType = json.get(System.identityHashCode(jsonMemberGroup));
+				Type newJsonType = null;
+				if (exp instanceof Term && ((Term) exp).getSymbol().equals(DataConstraintModel.dotParam)) {
+					if (DataConstraintModel.typeList.isAncestorOf(jsonType)) {
+						Type elementType = listComponentTypes.get(jsonType);
+						Type newElementType = getExpTypeIfUpdatable(elementType, exp);
+						if (newElementType != null) {
+							// Propagate an update of a member's type to its container's (json's) type.
+							newJsonType = listTypes.get(newElementType);
+							if (newJsonType == null) {
+								// Create new json type.
+								newJsonType = createNewListType(newElementType, jsonType);
+							}
+						}
+					} else if (DataConstraintModel.typeMap.isAncestorOf(jsonType)) {
+						List<Type> keyValueTypes = mapComponentTypes.get(jsonType);
+						Type newValueType = getExpTypeIfUpdatable(keyValueTypes.get(1), exp);
+						if (newValueType != null) {
+							// Propagate an update of a member's type to its container's (json's) type.
+							List<Type> newKeyValueTypes = Arrays.asList(new Type[] {DataConstraintModel.typeString, newValueType});
+							newJsonType = mapTypes.get(newKeyValueTypes);
+							if (newJsonType == null) {
+								// Create new json type.
+								newJsonType = createNewMapType(newKeyValueTypes, jsonType);
+							}
+						}
+					}
+				} else {
+					Map<String, Type> memberTypes = jsonMemberTypes.get(jsonType);
+					String keyName = null;
+					if (jsonMemberGroup.get(1) instanceof Constant) {
+						keyName = ((Constant) jsonMemberGroup.get(1)).getSymbol().getName();
+					}
+					if (memberTypes != null) {
+						Type memberType = memberTypes.get(keyName);
+						Type newMemberType = getExpTypeIfUpdatable(memberType, exp);
+						if (newMemberType != null && keyName != null) {
+							// Propagate an update of a member's type to its container's (json's) type.
+							Map<String, Type> newMemberTypes = new HashMap<>(memberTypes);
+							newMemberTypes.put(keyName, newMemberType);
+							newJsonType = jsonTypes.get(newMemberTypes);
+							if (newJsonType == null) {
+								// Create new json type.
+								newJsonType = createNewJsonType(newMemberTypes, jsonType);
+							}
+						}
+					}
+				}
+				if (newJsonType != null) {
+					// Update the type of the json term and record the updated expression.
+					Map<Integer, Expression> updateExps = getUpdateSet(updateFromJson, jsonMemberGroup);
+					Expression jsonExp = jsonMemberGroup.get(0);
+					if (jsonExp instanceof Variable) {
+						((Variable) jsonExp).setType(newJsonType);
+						updateExps.put(System.identityHashCode(jsonExp), jsonExp);
+					} else if (jsonExp instanceof Term) {
+						((Term) jsonExp).setType(newJsonType);
+						updateExps.put(System.identityHashCode(jsonExp), jsonExp);
+					}
+					json.put(System.identityHashCode(jsonMemberGroup), newJsonType);
+				}
+			}
+		}
+	}
+	
 	private static Type createNewListType(Type compType, Type parentType) {
 		String compTypeName = getInterfaceTypeName(compType);
 		List<Type> childrenTypes = getChildrenTypes(parentType, listComponentTypes.keySet());
@@ -1598,9 +1917,39 @@
 		return newMapType;
 	}
 
-	private static List<Type> getChildrenTypes(Type parentType, Set<Type> componentTypes) {
+	private static JsonType createNewJsonType(Map<String, Type> memberTypes, Type parentJsonType) {
+		String implTypeName = "HashMap<>";
+		String interfaceTypeName = "Map<String, Object>";
+		List<Type> childrenTypes = getChildrenTypes(parentJsonType, jsonMemberTypes.keySet());
+		JsonType newJsonType = new JsonType("Json", implTypeName, interfaceTypeName, parentJsonType);
+		for (String key: memberTypes.keySet()) {
+			newJsonType.addMemberType(key, memberTypes.get(key));
+		}
+		jsonTypes.put(memberTypes, newJsonType);
+		jsonMemberTypes.put(newJsonType, memberTypes);
+		for (Type childType : childrenTypes) {
+			if (compareTypes(childType, newJsonType)) {
+				if (newJsonType.getParentTypes().contains(parentJsonType)) {
+					newJsonType.replaceParentType(parentJsonType, childType);
+				} else {
+					newJsonType.addParentType(childType);
+				}
+			} else if (compareTypes(newJsonType, childType)) {
+				childType.replaceParentType(parentJsonType, newJsonType);
+			}
+		}
+		return newJsonType;
+	}
+
+	/**
+	 * Get children types of a given type from given set of types.
+	 * @param parentType a type
+	 * @param allTypes set of types
+	 * @return list of the children types
+	 */
+	private static List<Type> getChildrenTypes(Type parentType, Set<Type> allTypes) {
 		List<Type> childrenTypes = new ArrayList<>();
-		for (Type childType : componentTypes) {
+		for (Type childType : allTypes) {
 			if (childType.getParentTypes().contains(parentType)) {
 				childrenTypes.add(childType);
 			}
@@ -1626,8 +1975,7 @@
 		return type.getInterfaceTypeName();
 	}
 
-	private static <T extends Expression, U extends Collection<T>> Map<Integer, T> getUpdateSet(
-			Map<Integer, Map<Integer, T>> updateSets, U keySet) {
+	private static <T extends Expression, U extends Collection<T>> Map<Integer, T> getUpdateSet(Map<Integer, Map<Integer, T>> updateSets, U keySet) {
 		Map<Integer, T> updatedExps = updateSets.get(System.identityHashCode(keySet));
 		if (updatedExps == null) {
 			updatedExps = new HashMap<>();
@@ -1683,6 +2031,7 @@
 				for (int i = 0; i < originalCompTypes.size(); i++) {
 					if (originalCompTypes.get(i) != null) {
 						if (DataConstraintModel.typeTuple.isAncestorOf(originalCompTypes.get(i))) {
+							// Unfold the nested tuple's types.
 							Type tupleType = originalCompTypes.remove(i); 
 							for (Type t: tupleComponentTypes.get(tupleType)) {
 								originalCompTypes.add(t);
@@ -1690,6 +2039,7 @@
 						}
 						if (newCompTypes.size() - 1 < i) return false;
 						if (newCompTypes.get(i) != null && DataConstraintModel.typeTuple.isAncestorOf(newCompTypes.get(i))) {
+							// Unfold the nested tuple's types.
 							Type tupleType = newCompTypes.remove(i); 
 							for (Type t: tupleComponentTypes.get(tupleType)) {
 								newCompTypes.add(t);
@@ -1707,6 +2057,19 @@
 				if (originalCompType != null && (newCompType == null || !originalCompType.isAncestorOf(newCompType))) return false;
 				return true;
 			}
+			if (DataConstraintModel.typeJson.isAncestorOf(originalType) && DataConstraintModel.typeJson.isAncestorOf(newType)) {
+				Map<String, Type> originalMemberTypes = jsonMemberTypes.get(originalType);
+				Map<String, Type> newMemberTypes = jsonMemberTypes.get(newType);
+				if (originalMemberTypes == null) return true;
+				if (originalMemberTypes.keySet().size() < newMemberTypes.keySet().size() 
+						&& newMemberTypes.keySet().containsAll(originalMemberTypes.keySet())) return true;
+				if (originalMemberTypes.keySet().size() > newMemberTypes.keySet().size()) return false;
+				if (!newMemberTypes.keySet().containsAll(originalMemberTypes.keySet())) return false;
+				for (String key: originalMemberTypes.keySet()) {
+					if (!originalMemberTypes.get(key).isAncestorOf(newMemberTypes.get(key))) return false;
+				}
+				return true;
+			}
 		}
 		return false;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/application/editor/Editor.java b/AlgebraicDataflowArchitectureModel/src/application/editor/Editor.java
index ba453b8..522e0ca 100644
--- a/AlgebraicDataflowArchitectureModel/src/application/editor/Editor.java
+++ b/AlgebraicDataflowArchitectureModel/src/application/editor/Editor.java
@@ -49,6 +49,7 @@
 import parser.exceptions.ExpectedResource;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 import parser.ParserDTRAM;
@@ -253,7 +254,7 @@
 					return model;
 				} catch (ExpectedChannel | ExpectedChannelName | ExpectedLeftCurlyBracket | ExpectedInOrOutOrRefKeyword
 						| ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression | WrongLHSExpression
-						| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment | ExpectedModel | ExpectedGeometry | ExpectedNode | ExpectedResource | ExpectedFormulaChannel | ExpectedIoChannel e) {
+						| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment | ExpectedModel | ExpectedGeometry | ExpectedNode | ExpectedResource | ExpectedFormulaChannel | ExpectedIoChannel | WrongJsonExpression e) {
 					e.printStackTrace();
 				}
 			}
@@ -289,7 +290,7 @@
 				return model;
 			} catch (ExpectedChannel | ExpectedChannelName | ExpectedLeftCurlyBracket | ExpectedInOrOutOrRefKeyword
 					| ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression | WrongLHSExpression
-					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment e) {
+					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment | WrongJsonExpression e) {
 				e.printStackTrace();
 			}
 		} catch (FileNotFoundException e) {
diff --git a/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowCellEditor.java b/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowCellEditor.java
index 117067f..2b9e98a 100644
--- a/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowCellEditor.java
+++ b/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowCellEditor.java
@@ -33,6 +33,7 @@
 import parser.Parser;
 import parser.Parser.TokenStream;
 import parser.exceptions.ExpectedRightBracket;
+import parser.exceptions.WrongJsonExpression;
 
 /*************************************************************
  * 
@@ -120,7 +121,7 @@
 						Expression exp = parser.parseTerm(stream, stage.getModel());
 						((FormulaChannel) ch).setFormula(formula);
 						((FormulaChannel) ch).setFormulaTerm(exp);
-					} catch (ExpectedRightBracket e) {
+					} catch (ExpectedRightBracket | WrongJsonExpression e) {
 						e.printStackTrace();
 					}
 				}
diff --git a/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowModelingStage.java b/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowModelingStage.java
index b722f1b..3ba933f 100644
--- a/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowModelingStage.java
+++ b/AlgebraicDataflowArchitectureModel/src/application/editor/stages/DataFlowModelingStage.java
@@ -38,6 +38,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -49,6 +50,8 @@
 	public int PORT_DIAMETER = 8;
 	public int PORT_RADIUS = PORT_DIAMETER / 2;
 	
+	private boolean bReflectingArchitectureModel = false;
+	
 	/*************************************************************
 	 * [ *constructor]
 	 /*************************************************************
@@ -173,6 +176,7 @@
 	 * @return constructed mxGraph
 	 */
 	public mxGraph constructGraph(mxGraph graph, DataTransferModel model) {
+		bReflectingArchitectureModel = true;
 		mxCell root = (mxCell) graph.getDefaultParent();
 		mxCell nodeLayer = (mxCell) root.getChildAt(NODE_LAYER);
 		mxCell dataFlowLayer = (mxCell) root.getChildAt(DATA_FLOW_LAYER);
@@ -254,6 +258,7 @@
 			graph.getModel().endUpdate();
 		}
 
+		bReflectingArchitectureModel = false;
 		return graph;
 	}
 
@@ -351,6 +356,7 @@
 	}
 
 	public boolean connectEdge(mxCell edge, mxCell src, mxCell dst) {
+		if (bReflectingArchitectureModel) return false;
 		DataTransferModel model = getModel();
 		Channel srcCh = model.getChannel((String) src.getValue());
 		if (srcCh == null) {
@@ -449,7 +455,7 @@
 			}
 		} catch (ExpectedRightBracket | ExpectedChannel | ExpectedChannelName | ExpectedLeftCurlyBracket
 				| ExpectedInOrOutOrRefKeyword | ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression
-				| WrongLHSExpression | WrongRHSExpression | ExpectedAssignment e) {
+				| WrongLHSExpression | WrongRHSExpression | ExpectedAssignment | WrongJsonExpression e) {
 			e.printStackTrace();
 		}
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/CodeGenerator.java b/AlgebraicDataflowArchitectureModel/src/generators/CodeGenerator.java
index a61be75..315a158 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/CodeGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/CodeGenerator.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -74,7 +75,7 @@
 		ArrayList<CompilationUnit> codes = new ArrayList<>();
 		
 		// Sort the all components.
-		ArrayList<Node> components = determineComponentOrder(flowGraph);
+		ArrayList<Set<Node>> components = determineComponentOrder(flowGraph);
 		
 		// Add the main component.
 		if (mainTypeName == null) {
@@ -91,49 +92,75 @@
 		return codes;
 	}
 	
-	public abstract void generateCodeFromFlowGraph(DataTransferModel model, IFlowGraph flowGraph, ArrayList<Node> components,
+	public abstract void generateCodeFromFlowGraph(DataTransferModel model, IFlowGraph flowGraph, ArrayList<Set<Node>> components,
 			TypeDeclaration mainComponent, MethodDeclaration mainConstructor, ArrayList<CompilationUnit> codes, ILanguageSpecific langSpec);
 	
-	private static ArrayList<Node> determineComponentOrder(IFlowGraph graph) {
-		ArrayList<Node> objects = new ArrayList<>();
-		Set<Node> visited = new HashSet<>();
-		Set<Node> allNodes = graph.getAllNodes();
-		for (Node n: allNodes) {
-			if (!(n instanceof EntryPointObjectNode)) {
-				topologicalSort(allNodes, n, visited, objects);
+	private static ArrayList<Set<Node>> determineComponentOrder(IFlowGraph graph) {
+		ArrayList<Set<Node>> objects = new ArrayList<>();
+		Set<Set<Node>> visited = new HashSet<>();
+		Map<Node, Set<Node>> allNodeSets = graph.getAllNodes();
+		for (Set<Node> nodeSet: allNodeSets.values()) {
+			if (!(nodeSet.iterator().next() instanceof EntryPointObjectNode)) {
+				topologicalSort(allNodeSets, nodeSet, visited, objects);
 			}
 		}
 		return objects;
 	}
 	
-	private static void topologicalSort(Set<Node> allNodes, Node curNode, Set<Node> visited, List<Node> orderedList) {
-		if (visited.contains(curNode)) return;
-		visited.add(curNode);
+	private static void topologicalSort(Map<Node, Set<Node>> allNodeSets, Set<Node> curNodeSet, Set<Set<Node>> visited, List<Set<Node>> orderedList) {
+		if (visited.contains(curNodeSet)) return;
+		visited.add(curNodeSet);
 		// a caller is before the callee
-		for (Edge e: curNode.getInEdges()) {
-			if (!(e.getSource() instanceof EntryPointObjectNode)) {
-				if (!(e instanceof DataFlowEdge) || ((PushPullAttribute)((DataFlowEdge) e).getAttribute()).getOptions().get(0) == PushPullValue.PUSH) {
-					topologicalSort(allNodes, e.getSource(), visited, orderedList);
+		for (Node curNode: curNodeSet) {
+			for (Edge e: curNode.getInEdges()) {
+				if (!(e.getSource() instanceof EntryPointObjectNode)) {
+					if (!(e instanceof DataFlowEdge) || ((PushPullAttribute)((DataFlowEdge) e).getAttribute()).getOptions().get(0) == PushPullValue.PUSH) {
+						// for a call edge or PUSH data-flow edge
+						topologicalSort(allNodeSets, allNodeSets.get(e.getSource()), visited, orderedList);
+					}
 				}
 			}
 		}
-		if (curNode instanceof ResourceNode) {
-			for (Edge e: curNode.getOutEdges()) {
-				DataFlowEdge de = (DataFlowEdge) e;
-				if (((PushPullAttribute) de.getAttribute()).getOptions().get(0) != PushPullValue.PUSH) {
-					topologicalSort(allNodes, e.getDestination(), visited, orderedList);
+//		if (curNode instanceof StatefulObjectNode) {
+//			ResourceNode resNode = ((StatefulObjectNode) curNode).getResource();
+//			for (Node n: allNodes) {
+//				if (n != curNode && n instanceof StatefulObjectNode && !visited.contains(n)) {
+//					if (resNode.equals(((StatefulObjectNode) n).getResource())) {
+//						// n and curNode are identical (one in PUSH call graph and another in PULL call graph).
+//						visited.add(n);
+//						for (Edge e: n.getInEdges()) {
+//							if (!(e.getSource() instanceof EntryPointObjectNode)) {
+//								if (!(e instanceof DataFlowEdge)) {
+//									// for a call edge
+//									topologicalSort(allNodes, e.getSource(), visited, orderedList);
+//								}
+//							}
+//						}
+//					}
+//				}
+//			}
+//		}
+		if (curNodeSet.iterator().next() instanceof ResourceNode) {
+			for (Node curNode: curNodeSet) {
+				for (Edge e: curNode.getOutEdges()) {
+					DataFlowEdge de = (DataFlowEdge) e;
+					if (((PushPullAttribute) de.getAttribute()).getOptions().get(0) != PushPullValue.PUSH) {
+						// for a PULL data-flow edge
+						topologicalSort(allNodeSets, allNodeSets.get(e.getDestination()), visited, orderedList);
+					}
 				}
 			}
 		}
 		// For reference resources.
 		ResourceNode cn = null;
+		Node curNode = curNodeSet.iterator().next();
 		if (curNode instanceof ResourceNode) {
 			cn = (ResourceNode) curNode;
 		} else if (curNode instanceof StatefulObjectNode) {
 			cn = ((StatefulObjectNode) curNode).getResource();
 		}
 		if (cn != null) {
-			for (Node n: allNodes) {
+			for (Node n: allNodeSets.keySet()) {
 				ResourceNode rn = null;
 				if (n instanceof ResourceNode) {
 					rn = (ResourceNode) n;
@@ -145,14 +172,14 @@
 						DataTransferChannel ch = ((DataFlowEdge) e).getChannel();
 						for (ChannelMember m: ch.getReferenceChannelMembers()) {
 							if (m.getResource() == cn.getResource()) {
-								topologicalSort(allNodes, n, visited, orderedList);
+								topologicalSort(allNodeSets, allNodeSets.get(n), visited, orderedList);
 							}
 						}
 					}
 				}
 			}
 		}
-		orderedList.add(0, curNode);
+		orderedList.add(0, curNodeSet);
 	}
 
 	protected void updateMainComponent(DataTransferModel model, TypeDeclaration mainType, MethodDeclaration mainConstructor, Node componentNode, 
@@ -245,10 +272,10 @@
 		}
 	}
 
-	protected void declareAccessorInMainComponent(TypeDeclaration mainComponent, ResourcePath accessResId, ILanguageSpecific langSpec) {
-		MethodDeclaration getter = new MethodDeclaration("get" + langSpec.toComponentName(accessResId.getResourceName()), accessResId.getResourceStateType());
+	protected void declareAccessorInMainComponent(TypeDeclaration mainComponent, ResourcePath accessRes, ILanguageSpecific langSpec) {
+		MethodDeclaration getter = langSpec.newMethodDeclaration("get" + langSpec.toComponentName(accessRes.getResourceName()), accessRes.getResourceStateType());
 		Block block = new Block();
-		block.addStatement(langSpec.getReturnStatement(langSpec.getMethodInvocation(accessResId.getResourceName(), getterOfResourceState)) + langSpec.getStatementDelimiter());
+		block.addStatement(langSpec.getReturnStatement(langSpec.getMethodInvocation(accessRes.getResourceName(), getterOfResourceState)) + langSpec.getStatementDelimiter());
 		getter.setBody(block);
 		mainComponent.addMethod(getter);
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromControlFlowGraph.java b/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromControlFlowGraph.java
index 5ec1584..261e4dc 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromControlFlowGraph.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromControlFlowGraph.java
@@ -48,7 +48,7 @@
 public class CodeGeneratorFromControlFlowGraph extends CodeGenerator {
 
 	@Override
-	public void generateCodeFromFlowGraph(DataTransferModel model, IFlowGraph flowGraph, ArrayList<Node> components,
+	public void generateCodeFromFlowGraph(DataTransferModel model, IFlowGraph flowGraph, ArrayList<Set<Node>> components,
 			TypeDeclaration mainComponent, MethodDeclaration mainConstructor, ArrayList<CompilationUnit> codes, ILanguageSpecific langSpec) {
 		// Reconstruct data-flow information.
 		Map<Edge, Map<PushPullValue, List<ResourceNode>>> dataFlowInform = new HashMap<>();
@@ -64,32 +64,35 @@
 			removeRedundantAttributes(root, dataFlowInform);
 		}
 		
-		// For each of other components.
+		// For each component other than the main component.
 		Map<Node, TypeDeclaration> componentMap = new HashMap<>();
-		for (Node componentNode: components) {
+		for (Set<Node> componentNodeSet: components) {
 			// Declare this component.
+			Node componentNode = componentNodeSet.iterator().next();
 			String componentName = langSpec.toComponentName(((ObjectNode) componentNode).getName());
 			TypeDeclaration component = langSpec.newTypeDeclaration(componentName);
-			componentMap.put(componentNode, component);
+			for (Node compNode: componentNodeSet) {
+				componentMap.put(compNode, component);
+			}
 			
 			// Declare the constructor and the fields to refer to the callee components.
 			List<ResourcePath> depends = new ArrayList<>();
-			MethodDeclaration constructor = declareConstructorAndFieldsToCalleeComponents((ObjectNode) componentNode, component, depends, langSpec);
+			MethodDeclaration constructor = declareConstructorAndFieldsToCalleeComponents(componentNodeSet, component, depends, langSpec);
 			
 			if (componentNode instanceof StatefulObjectNode) {
 				// For this resource.
 				ResourceNode resourceNode = ((StatefulObjectNode) componentNode).getResource();
-				ResourcePath resId = resourceNode.getResource();
-				Type resStateType = resId.getResourceStateType();
+				ResourcePath res = resourceNode.getResource();
+				Type resStateType = res.getResourceStateType();
 				
 				// Declare the field in this resource to store the state.
 				if (((StoreAttribute) resourceNode.getAttribute()).isStored()) {
-					FieldDeclaration stateField = langSpec.newFieldDeclaration(resStateType, fieldOfResourceState, langSpec.getFieldInitializer(resStateType, resId.getInitialValue()));
+					FieldDeclaration stateField = langSpec.newFieldDeclaration(resStateType, fieldOfResourceState, langSpec.getFieldInitializer(resStateType, res.getInitialValue()));
 					component.addField(stateField);
 				}
 				
 				// Declare the accessor method in the main component to call the getter method.
-				declareAccessorInMainComponent(mainComponent, resId, langSpec);
+				declareAccessorInMainComponent(mainComponent, res, langSpec);
 				
 				// Declare the fields to refer to reference resources.
 				declareFieldsToReferenceResources(model, resourceNode, component, constructor, depends, langSpec);				
@@ -242,7 +245,7 @@
 		}
 	}
 	
-	private MethodDeclaration declareConstructorAndFieldsToCalleeComponents(ObjectNode componentNode, TypeDeclaration component, 
+	private MethodDeclaration declareConstructorAndFieldsToCalleeComponents(Set<Node> componentNodeSet, TypeDeclaration component, 
 			List<ResourcePath> depends, ILanguageSpecific langSpec) {
 		// Declare a constructor in each component.
 		MethodDeclaration constructor = component.createConstructor();
@@ -250,12 +253,14 @@
 		constructor.setBody(block);
 		
 		// Declare fields in each component. (for control-flow graph)
-		for (Edge e: componentNode.getOutEdges()) {
-			ObjectNode dstNode = (ObjectNode) e.getDestination();
-			addReference(component, constructor, dstNode, langSpec);
-			if (dstNode instanceof StatefulObjectNode) {
-				ResourcePath dstId = ((StatefulObjectNode) dstNode).getResource().getResource();
-				if (!depends.contains(dstId)) depends.add(dstId);
+		for (Node componentNode: componentNodeSet) {
+			for (Edge e: componentNode.getOutEdges()) {
+				ObjectNode dstNode = (ObjectNode) e.getDestination();
+				addReference(component, constructor, dstNode, langSpec);
+				if (dstNode instanceof StatefulObjectNode) {
+					ResourcePath dstRes = ((StatefulObjectNode) dstNode).getResource().getResource();
+					if (!depends.contains(dstRes)) depends.add(dstRes);
+				}
 			}
 		}
 		return constructor;
@@ -291,33 +296,33 @@
 				DataTransferChannel ch = null;
 				HashMap<ResourcePath, IResourceStateAccessor> inputResourceToStateAccessor = new HashMap<>();
 				for (Edge eIn: resourceNode.getInEdges()) {
-					DataFlowEdge dIn = (DataFlowEdge) eIn;
-					if (((PushPullAttribute) dIn.getAttribute()).getOptions().get(0) == PushPullValue.PUSH) {
+					DataFlowEdge dataFlowInEdge = (DataFlowEdge) eIn;
+					if (((PushPullAttribute) dataFlowInEdge.getAttribute()).getOptions().get(0) == PushPullValue.PUSH) {
 						// PUSH data transfer
 						isContainedPush = true;
-						inputResourceToStateAccessor.put(((ResourceNode) dIn.getSource()).getResource(), getPushAccessor());
+						inputResourceToStateAccessor.put(((ResourceNode) dataFlowInEdge.getSource()).getResource(), getPushAccessor());
 					} else {
 						// PULL data transfer
-						for (Edge outEdge: node.getOutEdges()) {
+						for (Edge callEdge: node.getOutEdges()) {
 							// For each call edge.
-							ObjectNode dstNode = (ObjectNode) outEdge.getDestination();
-							List<ResourceNode> returnedResources = dataFlowInform.get(outEdge).get(PushPullValue.PULL);
-							if (returnedResources.contains((ResourceNode) dIn.getSource())) {
+							ObjectNode calledNode = (ObjectNode) callEdge.getDestination();
+							List<ResourceNode> returnedResources = dataFlowInform.get(callEdge).get(PushPullValue.PULL);
+							if (returnedResources.contains((ResourceNode) dataFlowInEdge.getSource())) {
 								if (returnedResources.size() == 1) {
-									MethodDeclaration nextGetter = declareAndFillGetterMethods(dstNode, outEdge, dataFlowInform, componentMap, langSpec);
-									inputResourceToStateAccessor.put(((ResourceNode) dIn.getSource()).getResource(), getPullAccessor(dstNode.getName(), nextGetter.getName()));
+									MethodDeclaration nextGetter = declareAndFillGetterMethods(calledNode, callEdge, dataFlowInform, componentMap, langSpec);
+									inputResourceToStateAccessor.put(((ResourceNode) dataFlowInEdge.getSource()).getResource(), getPullAccessor(calledNode.getName(), nextGetter.getName()));
 									break;
 								} else {
-									MethodDeclaration nextGetter = declareAndFillGetterMethods(dstNode, outEdge, dataFlowInform, componentMap, langSpec);
-									int idx = returnedResources.indexOf((ResourceNode) dIn.getSource());
+									MethodDeclaration nextGetter = declareAndFillGetterMethods(calledNode, callEdge, dataFlowInform, componentMap, langSpec);
+									int idx = returnedResources.indexOf((ResourceNode) dataFlowInEdge.getSource());
 									int len = returnedResources.size();
-									inputResourceToStateAccessor.put(((ResourceNode) dIn.getSource()).getResource(), 
-											getPullAccessor(langSpec.getTupleGet(langSpec.getMethodInvocation(langSpec.getFieldAccessor(dstNode.getName()), nextGetter.getName()), idx, len)));
+									inputResourceToStateAccessor.put(((ResourceNode) dataFlowInEdge.getSource()).getResource(), 
+											getPullAccessor(langSpec.getTupleGet(langSpec.getMethodInvocation(langSpec.getFieldAccessor(calledNode.getName()), nextGetter.getName()), idx, len)));
 									break;
 								}
 							}
 						}
-						ch = dIn.getChannel();		// Always unique.
+						ch = dataFlowInEdge.getChannel();		// Always unique.
 					}
 				}
 				// For reference channel members.
@@ -354,16 +359,18 @@
 				// Unexpected.
 			}
 			getterMethodName += langSpec.toComponentName(returnedRes.getResource().getResourceName()) + "Value";
-			MethodDeclaration mediateGetter = langSpec.newMethodDeclaration(getterMethodName, returnedRes.getResource().getResourceStateType());
+			MethodDeclaration mediateGetter = getMethod(component, getterMethodName);
+			if (mediateGetter != null) return mediateGetter;
+			mediateGetter = langSpec.newMethodDeclaration(getterMethodName, returnedRes.getResource().getResourceStateType());
 			component.addMethod(mediateGetter);
 			
 			// Add a return statement.
 			if (node.getOutdegree() == 1) {
-				Edge outEdge = node.getOutEdges().iterator().next();
-				ObjectNode dstNode = (ObjectNode) outEdge.getDestination();
-				MethodDeclaration nextGetter = declareAndFillGetterMethods(dstNode, outEdge, dataFlowInform, componentMap, langSpec);
+				Edge callEdge = node.getOutEdges().iterator().next();
+				ObjectNode calledNode = (ObjectNode) callEdge.getDestination();
+				MethodDeclaration nextGetter = declareAndFillGetterMethods(calledNode, callEdge, dataFlowInform, componentMap, langSpec);
 				mediateGetter.addStatement(
-						langSpec.getReturnStatement(langSpec.getMethodInvocation(langSpec.getFieldAccessor(dstNode.getName()), nextGetter.getName()))
+						langSpec.getReturnStatement(langSpec.getMethodInvocation(langSpec.getFieldAccessor(calledNode.getName()), nextGetter.getName()))
 						+ langSpec.getStatementDelimiter());
 			} else {
 				// Unexpected.
@@ -376,8 +383,10 @@
 			getterMethodName += langSpec.toComponentName(rn.getResource().getResourceName());
 		}
 		getterMethodName += "Values";
+		MethodDeclaration mediateGetter = getMethod(component, getterMethodName);
+		if (mediateGetter != null) return mediateGetter;
 		Type returnType = createReturnType(resourcesToReturn, langSpec);
-		MethodDeclaration mediateGetter = langSpec.newMethodDeclaration(getterMethodName, returnType);
+		mediateGetter = langSpec.newMethodDeclaration(getterMethodName, returnType);
 		component.addMethod(mediateGetter);
 		
 		// Add a return statement.
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java b/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java
index 4873a2a..4de8146 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/CodeGeneratorFromDataFlowGraph.java
@@ -39,11 +39,12 @@
 
 public class CodeGeneratorFromDataFlowGraph extends CodeGenerator {
 
-	public void generateCodeFromFlowGraph(DataTransferModel model, IFlowGraph flowGraph, ArrayList<Node> components,
+	public void generateCodeFromFlowGraph(DataTransferModel model, IFlowGraph flowGraph, ArrayList<Set<Node>> components,
 			TypeDeclaration mainComponent, MethodDeclaration mainConstructor, ArrayList<CompilationUnit> codes, ILanguageSpecific langSpec) {
 		// For each of other components.
-		for (Node componentNode: components) {
+		for (Set<Node> componentNodeSet: components) {
 			// Declare this resource.
+			Node componentNode = componentNodeSet.iterator().next();
 			ResourceNode resourceNode = (ResourceNode) componentNode;
 			String resourceName = langSpec.toComponentName(resourceNode.getResource().getResourceName());
 			TypeDeclaration component = langSpec.newTypeDeclaration(resourceName);
@@ -55,12 +56,12 @@
 			// Update the main component for this component.
 			updateMainComponent(model, mainComponent, mainConstructor, componentNode, depends, langSpec);
 			
-			ResourcePath resId = resourceNode.getResource();
-			Type resStateType = resId.getResourceStateType();
+			ResourcePath res = resourceNode.getResource();
+			Type resStateType = res.getResourceStateType();
 			
 			// Declare the field in this resource to store the state.
 			if (((StoreAttribute) resourceNode.getAttribute()).isStored()) {
-				FieldDeclaration stateField = langSpec.newFieldDeclaration(resStateType, fieldOfResourceState, langSpec.getFieldInitializer(resStateType, resId.getInitialValue()));
+				FieldDeclaration stateField = langSpec.newFieldDeclaration(resStateType, fieldOfResourceState, langSpec.getFieldInitializer(resStateType, res.getInitialValue()));
 				component.addField(stateField);
 			}
 			
@@ -68,7 +69,7 @@
 			MethodDeclaration getter = declareGetterMethod(resourceNode, component, resStateType, langSpec);
 			
 			// Declare the accessor method in the main component to call the getter method.
-			declareAccessorInMainComponent(mainComponent, resId, langSpec);
+			declareAccessorInMainComponent(mainComponent, res, langSpec);
 			
 			// Declare the fields to refer to reference resources.
 			declareFieldsToReferenceResources(model, resourceNode, component, constructor, depends, langSpec);
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/ILanguageSpecific.java b/AlgebraicDataflowArchitectureModel/src/generators/ILanguageSpecific.java
index 38e4e0a..35e67ce 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/ILanguageSpecific.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/ILanguageSpecific.java
@@ -17,9 +17,11 @@
 	TypeDeclaration newTypeDeclaration(String typeName);
 	VariableDeclaration newVariableDeclaration(Type type, String varName);
 	MethodDeclaration newMethodDeclaration(String methodName, Type returnType);
-	MethodDeclaration newMethodDeclaration(String methodName, boolean isConstructor, Type returnType, ArrayList<VariableDeclaration> parameters);
+	MethodDeclaration newMethodDeclaration(String methodName, boolean isConstructor, Type returnType, List<VariableDeclaration> parameters);
 	FieldDeclaration newFieldDeclaration(Type fieldType, String fieldName);
 	FieldDeclaration newFieldDeclaration(Type fieldType, String fieldName, String fieldInitializer);
+	Type newListType(String compTypeName);
+	Type newMapType(Type keyType, String compTypeName);
 	Type newTupleType(List<Type> compTypes);
 	String getVariableDeclaration(String typeName, String varName);
 	String getFieldInitializer(Type type, Expression initialValue);
@@ -31,6 +33,7 @@
 	String getConstructorInvocation(String componentName, List<String> parameters);
 	String getReturnStatement(String returnValue);
 	String toComponentName(String name);
+	String toVariableName(String name);
 	String getMainComponentName();
 	String getTupleGet(String tupleExp, int idx, int length);
 	String getDecomposedTuple(String tupleExp, VariableDeclaration tupleVar, List<VariableDeclaration> vars);
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java b/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java
index 585754a..34590cf 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/JavaCodeGenerator.java
@@ -111,13 +111,13 @@
 				}
 			}
 			Set<ResourcePath> refs = new HashSet<>();
-			for (Channel cg : model.getChannels()) {
-				DataTransferChannel c = (DataTransferChannel) cg;
+			for (Channel ch : model.getChannels()) {
+				DataTransferChannel c = (DataTransferChannel) ch;
 				if (c.getInputResources().contains(rn.getResource())) {
-					for (ResourcePath id: c.getReferenceResources()) {
-						if (!refs.contains(id) && !depends.contains(id)) {
-							refs.add(id);
-							String refResName = id.getResourceName();
+					for (ResourcePath res: c.getReferenceResources()) {
+						if (!refs.contains(res) && !depends.contains(res)) {
+							refs.add(res);
+							String refResName = res.getResourceName();
 							fieldInitializer += refResName.toLowerCase() + ",";
 							f = true;
 						}
@@ -128,12 +128,12 @@
 			fieldInitializer += ")";
 			FieldDeclaration field = new FieldDeclaration(new Type(resourceName, resourceName), rn.getResource().getResourceName());
 			mainType.addField(field);
-			Block manConstructorBody = mainConstructor.getBody();
-			if (manConstructorBody == null) {
-				manConstructorBody = new Block();
-				mainConstructor.setBody(manConstructorBody);
+			Block mainConstructorBody = mainConstructor.getBody();
+			if (mainConstructorBody == null) {
+				mainConstructorBody = new Block();
+				mainConstructor.setBody(mainConstructorBody);
 			}
-			manConstructorBody.addStatement(rn.getResource().getResourceName() + " = " + fieldInitializer + ";");
+			mainConstructorBody.addStatement(rn.getResource().getResourceName() + " = " + fieldInitializer + ";");
 			
 			// Declare a constructor, fields and update methods in the type of each resource.
 			MethodDeclaration constructor = new MethodDeclaration(resourceName, true);
@@ -176,17 +176,17 @@
 			}
 			// Declare a field to refer to the reference resource.
 			refs = new HashSet<>();
-			for (Channel cg : model.getChannels()) {
-				DataTransferChannel c = (DataTransferChannel) cg;
+			for (Channel ch : model.getChannels()) {
+				DataTransferChannel c = (DataTransferChannel) ch;
 				if (c.getInputResources().contains(rn.getResource())) {
-					for (ResourcePath id: c.getReferenceResources()) {
-						if (!refs.contains(id) && !depends.contains(id)) {
-							refs.add(id);
-							String refResName = id.getResourceName();
+					for (ResourcePath res: c.getReferenceResources()) {
+						if (!refs.contains(res) && !depends.contains(res)) {
+							refs.add(res);
+							String refResName = res.getResourceName();
 							refResName = refResName.substring(0, 1).toUpperCase() + refResName.substring(1);
-							type.addField(new FieldDeclaration(new Type(refResName, refResName), id.getResourceName()));
-							constructor.addParameter(new VariableDeclaration(new Type(refResName, refResName), id.getResourceName()));						
-							block.addStatement("this." + id.getResourceName() + " = " + id.getResourceName() + ";");
+							type.addField(new FieldDeclaration(new Type(refResName, refResName), res.getResourceName()));
+							constructor.addParameter(new VariableDeclaration(new Type(refResName, refResName), res.getResourceName()));						
+							block.addStatement("this." + res.getResourceName() + " = " + res.getResourceName() + ";");
 						}
 					}
 				}
@@ -196,11 +196,11 @@
 				type.addMethod(constructor);
 			
 			// Declare input methods in resources and the main type.
-			for (Channel cg : model.getIOChannels()) {
-				for (ChannelMember cm : ((DataTransferChannel) cg).getOutputChannelMembers()) {
+			for (Channel ch : model.getIOChannels()) {
+				for (ChannelMember cm : ((DataTransferChannel) ch).getOutputChannelMembers()) {
 					if (cm.getResource().equals(rn.getResource())) {
 						Expression message = cm.getStateTransition().getMessageExpression();
-						if (message.getClass() == Term.class) {
+						if (message instanceof Term) {
 							ArrayList<VariableDeclaration> params = new ArrayList<>();
 							for (Variable var: message.getVariables().values()) {
 								params.add(new VariableDeclaration(var.getType(), var.getName()));
@@ -226,7 +226,7 @@
 									}
 								}
 							}
-						} else if (message.getClass() == Variable.class) {
+						} else if (message instanceof Variable) {
 							MethodDeclaration input = new MethodDeclaration(
 									((Variable) cm.getStateTransition().getMessageExpression()).getName(),
 									false, typeVoid, null);
@@ -244,8 +244,8 @@
 			
 			// Declare the field to store the state in the type of each resource.
 			if (((StoreAttribute) rn.getAttribute()).isStored()) {
-				ResourcePath resId = rn.getResource();
-				type.addField(new FieldDeclaration(resId.getResourceStateType(), "value", getInitializer(resId)));
+				ResourcePath res = rn.getResource();
+				type.addField(new FieldDeclaration(res.getResourceStateType(), "value", getInitializer(res)));
 			}
 			
 			// Declare the getter method to obtain the state in the type of each resource.
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/JavaSpecific.java b/AlgebraicDataflowArchitectureModel/src/generators/JavaSpecific.java
index 0176b5e..f9ffe2c 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/JavaSpecific.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/JavaSpecific.java
@@ -46,7 +46,7 @@
 	}
 
 	@Override
-	public MethodDeclaration newMethodDeclaration(String methodName, boolean isConstructor, Type returnType, ArrayList<VariableDeclaration> parameters) {
+	public MethodDeclaration newMethodDeclaration(String methodName, boolean isConstructor, Type returnType, List<VariableDeclaration> parameters) {
 		if (returnType == null) {
 			returnType = typeVoid;
 		}
@@ -64,6 +64,16 @@
 	}
 	
 	@Override
+	public Type newListType(String compTypeName) {
+		return new Type("List", "ArrayList<>", "List<" + compTypeName + ">", DataConstraintModel.typeList);		
+	}
+	
+	@Override
+	public Type newMapType(Type keyType, String valueTypeName) {
+		return new Type("Map", "HashMap<>", "Map<" + keyType.getImplementationTypeName() + ", " + valueTypeName + ">", DataConstraintModel.typeMap);		
+	}
+	
+	@Override
 	public Type newTupleType(List<Type> componentTypes) {
 		String implTypeName = "AbstractMap.SimpleEntry<>";
 		String interfaceTypeName = "Map.Entry<$x>";
@@ -169,6 +179,11 @@
 	}
 
 	@Override
+	public String toVariableName(String name) {
+		return name.substring(0, 1).toLowerCase() + name.substring(1);
+	}
+
+	@Override
 	public String getMainComponentName() {
 		return "Main";
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/generators/JerseyCodeGenerator.java b/AlgebraicDataflowArchitectureModel/src/generators/JerseyCodeGenerator.java
index 20f61f7..d191a18 100644
--- a/AlgebraicDataflowArchitectureModel/src/generators/JerseyCodeGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/generators/JerseyCodeGenerator.java
@@ -149,11 +149,11 @@
 //			}
 			
 			// Declare input methods in resources.
-			for (Channel cg : model.getIOChannels()) {
-				for (ChannelMember cm : ((DataTransferChannel) cg).getOutputChannelMembers()) {
+			for (Channel ch : model.getIOChannels()) {
+				for (ChannelMember cm : ((DataTransferChannel) ch).getOutputChannelMembers()) {
 					if (cm.getResource().equals(rn.getResource())) {
 						Expression message = cm.getStateTransition().getMessageExpression();
-						if (message.getClass() == Term.class) {
+						if (message instanceof Term) {
 							ArrayList<VariableDeclaration> params = new ArrayList<>();
 							for (Variable var: message.getVariables().values()) {
 								String paramName = var.getName();
@@ -170,7 +170,7 @@
 								input.addAnnotation(new Annotation("POST"));
 							}
 							type.addMethod(input);
-						} else if (message.getClass() == Variable.class) {
+						} else if (message instanceof Variable) {
 							MethodDeclaration input = new MethodDeclaration(
 									((Variable) cm.getStateTransition().getMessageExpression()).getName(),
 									false, typeVoid, null);
@@ -187,8 +187,8 @@
 			
 			// Declare the field to store the state in the type of each resource.
 			if (((StoreAttribute) rn.getAttribute()).isStored()) {
-				ResourcePath resId = rn.getResource();
-				type.addField(new FieldDeclaration(resId.getResourceStateType(), "value", getInitializer(resId)));
+				ResourcePath res = rn.getResource();
+				type.addField(new FieldDeclaration(res.getResourceStateType(), "value", getInitializer(res)));
 			}
 			
 			// Declare the getter method to obtain the state in the type of each resource.
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java
index a16fac5..81b24ed 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Term.java
@@ -327,7 +327,12 @@
 		}
 		if (getArity() >= 1 && symbol.isImplMethod()) {
 			if (implParamOrder == null) {
-				String exp = children.get(0).toImplementation(sideEffects) + "." + symbol.toImplementation() + "(";
+				String exp = null;
+				if (children.get(0) != null) {
+					exp = children.get(0).toImplementation(sideEffects) + "." + symbol.toImplementation() + "(";
+				} else {
+					exp = symbol.toImplementation() + "(";
+				}
 				String delimiter = "";
 				for (int i = 1; i < children.size(); i++) {
 					Expression e = children.get(i);
@@ -337,7 +342,11 @@
 				exp += ")";
 				if (symbol.isImplWithSideEffect()) {
 					sideEffects[0] = sideEffects[0] + exp + ";\n";
-					exp = children.get(0).toImplementation(new String[] {""});
+					if (children.get(0) != null) {
+						exp = children.get(0).toImplementation(new String[] {""});
+					} else {
+						exp = "";
+					}
 				}
 				return exp;
 			} else {
diff --git a/AlgebraicDataflowArchitectureModel/src/models/algebra/Type.java b/AlgebraicDataflowArchitectureModel/src/models/algebra/Type.java
index 50b0285..eb827bf 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/algebra/Type.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/algebra/Type.java
@@ -9,28 +9,28 @@
 	private String interfaceTypeName;
 	private List<Type> parentTypes = new ArrayList<>();
 	
-	public Type(String typeName, String implementastionTypeName) {
+	public Type(String typeName, String implementationTypeName) {
 		this.typeName = typeName;
-		this.implementationTypeName = implementastionTypeName;
-		this.interfaceTypeName = implementastionTypeName;
+		this.implementationTypeName = implementationTypeName;
+		this.interfaceTypeName = implementationTypeName;
 	}
 	
-	public Type(String typeName, String implementastionTypeName, String interfaceTypeName) {
+	public Type(String typeName, String implementationTypeName, String interfaceTypeName) {
 		this.typeName = typeName;
-		this.implementationTypeName = implementastionTypeName;
+		this.implementationTypeName = implementationTypeName;
 		this.interfaceTypeName = interfaceTypeName;
 	}
 
-	public Type(String typeName, String implementastionTypeName, Type parentType) {
+	public Type(String typeName, String implementationTypeName, Type parentType) {
 		this.typeName = typeName;
-		this.implementationTypeName = implementastionTypeName;
-		this.interfaceTypeName = implementastionTypeName;
+		this.implementationTypeName = implementationTypeName;
+		this.interfaceTypeName = implementationTypeName;
 		this.parentTypes.add(parentType);
 	}
 	
-	public Type(String typeName, String implementastionTypeName, String interfaceTypeName, Type parentType) {
+	public Type(String typeName, String implementationTypeName, String interfaceTypeName, Type parentType) {
 		this.typeName = typeName;
-		this.implementationTypeName = implementastionTypeName;
+		this.implementationTypeName = implementationTypeName;
 		this.interfaceTypeName = interfaceTypeName;
 		this.parentTypes.add(parentType);
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/models/controlFlowModel/ControlFlowGraph.java b/AlgebraicDataflowArchitectureModel/src/models/controlFlowModel/ControlFlowGraph.java
index 2913494..c2f9477 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/controlFlowModel/ControlFlowGraph.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/controlFlowModel/ControlFlowGraph.java
@@ -1,6 +1,9 @@
 package models.controlFlowModel;
 
+import java.util.Collection;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
 
 import models.Edge;
@@ -108,18 +111,31 @@
 	}
 	
 	@Override
-	public Set<Node> getAllNodes() {
-		Set<Node> allNodes = new HashSet<>();
-		allNodes.addAll(pushCallGraph.getNodes());
+	public Map<Node, Set<Node>> getAllNodes() {
+		Map<Node, Set<Node>> allNodeSets = new HashMap<>();
+		for (Node n: pushCallGraph.getNodes()) {
+			Set<Node> nodeSet = new HashSet<>();
+			nodeSet.add(n);
+			allNodeSets.put(n, nodeSet);
+		}
 		for (Node n: pullCallGraph.getNodes()) {
 			if (n instanceof StatefulObjectNode) {
-				if (pushCallGraph.getStatefulObjectNode(((StatefulObjectNode) n).getResource()) == null) {
-					allNodes.add(n);
+				ResourceNode resNode = ((StatefulObjectNode) n).getResource();
+				Set<Node> nodeSet = null;
+				if (pushCallGraph.getStatefulObjectNode(resNode) != null) {
+					// Merge a stateful object node in the push call graph and that in the pull call graph.
+					nodeSet = allNodeSets.get(pushCallGraph.getStatefulObjectNode(resNode));
+				} else {
+					nodeSet = new HashSet<>();
 				}
+				nodeSet.add(n);
+				allNodeSets.put(n, nodeSet);
 			} else {
-				allNodes.add(n);
+				Set<Node> nodeSet = new HashSet<>();
+				nodeSet.add(n);
+				allNodeSets.put(n, nodeSet);
 			}
 		}
-		return allNodes;
+		return allNodeSets;
 	}
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java
index aa6cee8..5adffa7 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/DataConstraintModel.java
@@ -31,9 +31,10 @@
 	public static final Type typePairInt = new Type("Pair", "Pair<Integer>", "Pair<Integer>", typePair);
 	public static final Type typePairStr = new Type("Pair", "Pair<String>", "Pair<String>", typePair);
 	public static final Type typePairDouble = new Type("Pair", "Pair<Double>", "Pair<Double>", typePair);
-	public static final Type typeMap = new Type("Map", "HashMap", "Map");
+	public static final Type typeMap = new Type("Map", "HashMap<>", "Map");
+	public static final JsonType typeJson = new JsonType("Json", "HashMap<>", "Map<String, Object>");
 	public static final Symbol add = new Symbol(Parser.ADD, 2, Symbol.Type.INFIX);
-	public static final Symbol mul = new Symbol(Parser.MUL, 2, Symbol.Type.INFIX);;
+	public static final Symbol mul = new Symbol(Parser.MUL, 2, Symbol.Type.INFIX);
 	public static final Symbol sub = new Symbol(Parser.SUB, 2, Symbol.Type.INFIX);
 	public static final Symbol div = new Symbol(Parser.DIV, 2, Symbol.Type.INFIX);
 	public static final Symbol minus = new Symbol(Parser.MINUS, 1);
@@ -147,6 +148,10 @@
 			return temp;
 		}
 	});
+	public static final Symbol json = new Symbol("json", 0, Symbol.Type.PREFIX, "new HashMap<>", Symbol.Type.METHOD);
+	public static final Symbol addMember = new Symbol("addMember", 3, Symbol.Type.PREFIX, "put", Symbol.Type.METHOD);
+	public static final Symbol dot = new Symbol(Parser.DOT, 2, Symbol.Type.INFIX, "get", Symbol.Type.METHOD);
+	public static final Symbol dotParam = new Symbol(Parser.DOT, 2, Symbol.Type.INFIX, "get", Symbol.Type.METHOD);
 	public static final Symbol pi = new Symbol("PI", 0, Symbol.Type.PREFIX, "Math.PI", Symbol.Type.PREFIX);
 	public static final Symbol E = new Symbol("E", 0, Symbol.Type.PREFIX, "Math.E", Symbol.Type.PREFIX);
 	public static final Symbol sqrt = new Symbol("sqrt", 1, Symbol.Type.PREFIX, "Math.sqrt", Symbol.Type.PREFIX);
@@ -198,6 +203,10 @@
 		snd.setInverses(new Symbol[] {new LambdaAbstraction(new Variable("y"), new Term(tuple, new Expression[] {new Variable("x"), new Variable("y")}))});
 		insert.setSignature(new Type[] {typeMap, typeMap, null, null});
 		lookup.setSignature(new Type[] {null, typeMap, null});
+		json.setSignature(new Type[] {typeJson});
+		addMember.setSignature(new Type[] {typeJson, typeJson, typeString, null});
+		dot.setSignature(new Type[] {null, typeJson, typeString});
+		dotParam.setSignature(new Type[] {null, null, null});
 		pi.setSignature(new Type[] {typeDouble});
 		E.setSignature(new Type[] {typeDouble});
 		sqrt.setSignature(new Type[] {typeDouble, typeDouble});
@@ -233,6 +242,7 @@
 		addType(typePair);
 		addType(typeTuple);
 		addType(typeMap);
+		addType(typeJson);
 		symbols = new HashMap<>();
 		addSymbol(add);
 		addSymbol(mul);
@@ -269,6 +279,10 @@
 		addSymbol(snd);
 		addSymbol(insert);
 		addSymbol(lookup);
+		addSymbol(json);
+		addSymbol(addMember);
+		addSymbol(dot);
+		addSymbol(dotParam);
 		addSymbol(pi);
 		addSymbol(E);
 		addSymbol(sqrt);
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonAccessor.java b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonAccessor.java
new file mode 100644
index 0000000..e591e07
--- /dev/null
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonAccessor.java
@@ -0,0 +1,142 @@
+package models.dataConstraintModel;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import models.algebra.Constant;
+import models.algebra.Expression;
+import models.algebra.LambdaAbstraction;
+import models.algebra.Position;
+import models.algebra.Symbol;
+import models.algebra.Term;
+import models.algebra.Type;
+import models.algebra.Variable;
+
+public class JsonAccessor extends Term {
+
+	public JsonAccessor(Symbol symbol) {
+		super(symbol);
+	}
+	
+	public Type getType() {
+		if (symbol.equals(DataConstraintModel.dotParam)) {
+			Type valueType = null;
+			if (getChild(1) instanceof Term) {
+				valueType = ((Term) getChild(1)).getType();
+			} else if (getChild(1) instanceof Variable) {
+				valueType = ((Variable) getChild(1)).getType();
+			}
+			if (valueType != null) return valueType;
+		}
+		return super.getType();
+	}
+	
+
+	@Override
+	public Expression getInverseMap(Expression outputValue, Position targetPos) {
+		if (targetPos.isEmpty()) return outputValue;
+		targetPos = (Position) targetPos.clone();
+		int i = targetPos.removeHeadOrder();
+		Symbol[] inverseSymbols = symbol.getInverses();
+		if (i == 0) {
+			if (symbol.equals(DataConstraintModel.dot) && getChildren().size() >= 2) {
+				// this term is `json.key`.
+				Expression expJson = getChild(0);
+				Expression expKey = getChild(1);
+				JsonType jsonType = null;
+				if (expJson instanceof Variable) {
+					jsonType = (JsonType) ((Variable) expJson).getType();
+				} else if (expJson instanceof Term) {
+					jsonType = (JsonType) ((Term) expJson).getType();
+				}
+				String keyName = null;
+				if (expKey instanceof Constant) {
+					keyName = ((Constant) expKey).getSymbol().getName();
+					Term jsonTerm = new Constant(DataConstraintModel.json);
+					int v = 1;
+					Map<String, Variable> vars = new HashMap<>();
+					Set<String> keySet = new HashSet<>();
+					if (jsonType == null || jsonType == DataConstraintModel.typeJson) {
+						keySet.add(keyName);
+					} else {
+						keySet.addAll(jsonType.getKeys());
+					}
+					for (String key: keySet) {
+						Term addMemberTerm = new Term(DataConstraintModel.addMember);	// addMember(jsonTerm, key, v)
+						addMemberTerm.addChild(jsonTerm);
+						addMemberTerm.addChild(new Constant(key));
+						Variable var = new Variable("v" + v);
+						addMemberTerm.addChild(var);
+						vars.put(key, var);
+						jsonTerm = addMemberTerm;
+						v++;
+					}
+					Variable var = vars.get(keyName);
+					LambdaAbstraction lambdaAbstraction = new LambdaAbstraction(var, jsonTerm);	// v -> addMember(jsonTerm, key, v)
+					inverseSymbols = new Symbol[] { lambdaAbstraction };
+				}
+			} else if (symbol.equals(DataConstraintModel.dotParam) && getChildren().size() >= 2) {
+				// this term is `json.{param}`.
+				Expression expListOrMap = getChild(0);
+				Expression expKey = getChild(1);
+				JsonType jsonType = null;
+				if (expListOrMap instanceof Variable) {
+					jsonType = (JsonType) ((Variable) expListOrMap).getType();
+				} else if (expListOrMap instanceof Term) {
+					jsonType = (JsonType) ((Term) expListOrMap).getType();
+				}
+				Type keyType = null;
+				if (expKey instanceof Variable) {
+					keyType = (JsonType) ((Variable) expKey).getType();
+				} else if (expKey instanceof Term) {
+					keyType = (JsonType) ((Term) expKey).getType();
+				}
+				if (jsonType != null && keyType != null) { 
+					if (DataConstraintModel.typeList.isAncestorOf(jsonType) || keyType.equals(DataConstraintModel.typeInt)) {
+						Term setElementTerm = new Term(DataConstraintModel.set);			// set(list, idx, v)
+						setElementTerm.addChild(new Constant(DataConstraintModel.nil));
+						setElementTerm.addChild(expKey);
+						Variable var = new Variable("v");
+						setElementTerm.addChild(var);
+						LambdaAbstraction lambdaAbstraction = new LambdaAbstraction(var, setElementTerm);	// v -> set(list, idx, v)
+						inverseSymbols = new Symbol[] { lambdaAbstraction };
+					} else if (DataConstraintModel.typeMap.isAncestorOf(jsonType) || keyType.equals(DataConstraintModel.typeString)) {
+						Term insertEntryTerm = new Term(DataConstraintModel.insert);			// insert(map, key, v)
+						insertEntryTerm.addChild(new Constant(DataConstraintModel.nil));
+						insertEntryTerm.addChild(expKey);
+						Variable var = new Variable("v");
+						insertEntryTerm.addChild(var);
+						LambdaAbstraction lambdaAbstraction = new LambdaAbstraction(var, insertEntryTerm);	// v -> insert(map, key, v)
+						inverseSymbols = new Symbol[] { lambdaAbstraction };
+					}
+				}
+			}
+		}
+		if (inverseSymbols == null || i >= inverseSymbols.length || inverseSymbols[i] == null) return null;
+		Term inverseMap = new Term(inverseSymbols[i]);
+		inverseMap.addChild(outputValue);
+		for (int n = 0; n < inverseSymbols[i].getArity(); n++) {
+			if (n != i) {
+				inverseMap.addChild(children.get(n));
+			}
+		}
+		return children.get(i).getInverseMap(inverseMap, targetPos);
+	}
+	
+	public String toString() {
+		if (symbol.equals(DataConstraintModel.dotParam)) {
+			return children.get(0).toString() + symbol.toString() + "{" + children.get(1).toString() + "}";		
+		}
+		return super.toString();
+	}
+	
+	public String toImplementation(String[] sideEffects) {
+		if (symbol.equals(DataConstraintModel.dotParam)) {
+			return children.get(0).toImplementation(sideEffects) + symbol.toImplementation() + "{" + children.get(1).toImplementation(sideEffects) + "}";		
+		}
+		return super.toImplementation(sideEffects);
+	}
+}
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonType.java b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonType.java
new file mode 100644
index 0000000..9f9e835
--- /dev/null
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/JsonType.java
@@ -0,0 +1,65 @@
+package models.dataConstraintModel;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+import models.algebra.Type;
+
+public class JsonType extends Type {
+	protected boolean isListOrMap = false;
+	protected Map<String, Type> memberTypes = null;
+	protected Type listOrMapElementType = null;
+	
+	public JsonType(String typeName, String implementationTypeName) {
+		super(typeName, implementationTypeName);
+		memberTypes = new HashMap<>();
+	}
+	
+	public JsonType(String typeName, String implementationTypeName, String interfaceTypeName) {
+		super(typeName, implementationTypeName, interfaceTypeName);
+		memberTypes = new HashMap<>();
+	}
+
+	public JsonType(String typeName, String implementationTypeName, Type parentType) {
+		super(typeName, implementationTypeName, parentType);
+		memberTypes = new HashMap<>();
+	}
+	
+	public JsonType(String typeName, String implementationTypeName, String interfaceTypeName, Type parentType) {
+		super(typeName, implementationTypeName, interfaceTypeName, parentType);
+		memberTypes = new HashMap<>();
+	}
+	
+	public Map<String, Type> getMemberTypes() {
+		return memberTypes;
+	}
+	
+	public Type getMemberType(String key) {
+		return memberTypes.get(key);
+	}
+	
+	public Set<String> getKeys() {
+		return memberTypes.keySet();
+	}
+	
+	public void addMemberType(String key, Type valueType) {
+		memberTypes.put(key, valueType);
+	}
+
+//	public boolean isListOrMap() {
+//		return isListOrMap;
+//	}
+//
+//	public void setListOrMap(boolean isListOrMap) {
+//		this.isListOrMap = isListOrMap;
+//	}
+
+	public Type getElementType() {
+		return listOrMapElementType;
+	}
+
+	public void setElementType(Type listElementType) {
+		this.listOrMapElementType = listElementType;
+	}
+}
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/DataFlowGraph.java b/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/DataFlowGraph.java
index 2a7660d..1b3a208 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/DataFlowGraph.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/DataFlowGraph.java
@@ -2,6 +2,7 @@
 
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 
@@ -51,7 +52,13 @@
 	}
 
 	@Override
-	public Set<Node> getAllNodes() {
-		return super.getNodes();
+	public Map<Node, Set<Node>> getAllNodes() {
+		Map<Node, Set<Node>> allNodeSets = new HashMap<>();
+		for (Node n: super.getNodes()) {
+			Set<Node> nodeSet = new HashSet<>();
+			nodeSet.add(n);
+			allNodeSets.put(n, nodeSet);
+		}
+		return allNodeSets;
 	}
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/IFlowGraph.java b/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/IFlowGraph.java
index 141c81f..d159bd7 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/IFlowGraph.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataFlowModel/IFlowGraph.java
@@ -1,9 +1,10 @@
 package models.dataFlowModel;
 
+import java.util.Map;
 import java.util.Set;
 
 import models.Node;
 
 public interface IFlowGraph {
-	abstract public Set<Node> getAllNodes();
+	abstract public Map<Node, Set<Node>> getAllNodes();
 }
diff --git a/AlgebraicDataflowArchitectureModel/src/parser/Parser.java b/AlgebraicDataflowArchitectureModel/src/parser/Parser.java
index 3713e9a..d74da73 100644
--- a/AlgebraicDataflowArchitectureModel/src/parser/Parser.java
+++ b/AlgebraicDataflowArchitectureModel/src/parser/Parser.java
@@ -1,6 +1,5 @@
 package parser;
 
-import java.awt.image.DataBufferDouble;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.util.ArrayList;
@@ -14,6 +13,8 @@
 import models.algebra.Type;
 import models.algebra.Variable;
 import models.dataConstraintModel.ChannelMember;
+import models.dataConstraintModel.DataConstraintModel;
+import models.dataConstraintModel.JsonAccessor;
 import models.dataConstraintModel.ResourcePath;
 import models.dataConstraintModel.StateTransition;
 import models.dataFlowModel.DataTransferModel;
@@ -27,6 +28,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -59,7 +61,8 @@
 	public static final String ASSIGNMENT = "=";
 	public static final String COMMA = ",";
 	public static final String COLON = ":";
-
+	public static final String DOT = ".";
+	public static final String DOT_REGX = "\\.";
 
 	public Parser(final TokenStream stream) {
 		this.stream = stream;
@@ -79,12 +82,14 @@
 	}
 	
 	public DataTransferModel doParse() 
-			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment {
+			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, 
+			ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment, WrongJsonExpression {
 		return parseDataFlowModel();
 	}
 
 	public DataTransferModel parseDataFlowModel() 
-			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment {
+			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, 
+			ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment, WrongJsonExpression {
 		DataTransferModel model = new DataTransferModel();
 		DataTransferChannel channel;
 		while ((channel = parseChannel(model)) != null) {
@@ -102,7 +107,7 @@
 			ExpectedLeftCurlyBracket, ExpectedRightBracket, ExpectedAssignment,
 			ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, 
 			ExpectedChannel, ExpectedChannelName, ExpectedInOrOutOrRefKeyword, 
-			ExpectedStateTransition, ExpectedEquals
+			ExpectedStateTransition, ExpectedEquals, WrongJsonExpression
 	{
 		if (!stream.hasNext()) return null;
 		if (stream.checkNext().equals(RIGHT_CURLY_BRACKET)) return null;
@@ -152,7 +157,7 @@
 
 	public void parseInit(DataTransferModel model) 
 			throws 
-			ExpectedLeftCurlyBracket, ExpectedAssignment, ExpectedRHSExpression, WrongRHSExpression, ExpectedRightBracket 
+			ExpectedLeftCurlyBracket, ExpectedAssignment, ExpectedRHSExpression, WrongRHSExpression, ExpectedRightBracket, WrongJsonExpression 
 	{
 		String leftBracket = stream.next();
 		if (!leftBracket.equals(LEFT_CURLY_BRACKET)) throw new ExpectedLeftCurlyBracket(stream.getLine());
@@ -186,7 +191,7 @@
 	public ChannelMember parseChannelMember(DataTransferModel model, final String inOrOutOrRef) 
 			throws 
 			ExpectedRightBracket, ExpectedStateTransition, ExpectedEquals, 
-			ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression
+			ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, WrongJsonExpression
 	{
 		if (!stream.hasNext()) throw new ExpectedStateTransition(stream.getLine());
 		Expression leftTerm = parseTerm(stream, model);
@@ -240,7 +245,7 @@
 	}
 
 	public Expression parseTerm(TokenStream stream, DataTransferModel model) 
-			throws ExpectedRightBracket
+			throws ExpectedRightBracket, WrongJsonExpression
 	{
 		ArrayList<Expression> expressions = new ArrayList<>();
 		ArrayList<Symbol> operators = new ArrayList<>();
@@ -283,31 +288,29 @@
 					symbol.setArity(arity);
 					exp = term;
 				} else {
-					// constant or variable
-					try {
-						Symbol symbol = model.getSymbol(symbolName);
-						if (symbol != null && symbol.getArity() == 0) {
-							exp = new Constant(symbol);
-						} else {
+					// constant or variable or json access
+					Symbol symbol = model.getSymbol(symbolName);
+					if (symbol != null && symbol.getArity() == 0) {
+						// a constant
+						exp = new Constant(symbol);
+					} else {
+						if (Character.isDigit(symbolName.charAt(0))) {
+							// maybe a numerical value
+							if (stream.checkNext() != null && stream.checkNext().equals(DOT)) {
+								// Because tokens are separated by a DOT.
+								stream.next();
+								symbolName += DOT + stream.next();	// decimal fraction
+							}
 							Double d = Double.parseDouble(symbolName);
-							if (symbolName.contains(".")) {
+							// a numerical value
+							if (symbolName.contains(DOT)) {
 								exp = new Constant(symbolName, DataTransferModel.typeDouble);
 							} else {
 								exp = new Constant(symbolName, DataTransferModel.typeInt);
 							}
-						}
-					} catch (NumberFormatException e) {
-						if (stream.checkNext() != null && stream.checkNext().equals(COLON)) {
-							// when a type is specified.
-							stream.next();
-							String typeName = stream.next();
-							Type type = model.getType(typeName);
-							if (type == null) {
-								type = new Type(typeName, typeName);
-							}
-							exp = new Variable(symbolName, type);							
 						} else {
-							exp = new Variable(symbolName);
+							// a variable
+							exp = parseVariable(stream, model, symbolName);
 						}
 					}
 				}
@@ -324,16 +327,52 @@
 				break;
 			} else if (operator.equals(ADD)) {
 				operators.add(DataTransferModel.add);
+				stream.next();
 			} else if (operator.equals(MUL)) {
 				operators.add(DataTransferModel.mul);
+				stream.next();
 			} else if (operator.equals(SUB)) {
 				operators.add(DataTransferModel.sub);	// not minus
+				stream.next();
 			} else if (operator.equals(DIV)) {
 				operators.add(DataTransferModel.div);
+				stream.next();
+			} else if (operator.equals(DOT)) {
+				// json accessor
+				Expression exp = expressions.remove(0);
+				stream.next();		// DOT
+				if (stream.checkNext() == null) throw new WrongJsonExpression(stream.getLine());
+				String literalOrLeftCurlyBracket = stream.next();
+				Expression paramTerm = null;
+				if (literalOrLeftCurlyBracket.equals(LEFT_CURLY_BRACKET)) {
+					// parameter
+					paramTerm = parseTerm(stream, model);
+					String rightCurlyBracket = stream.next();
+					if (rightCurlyBracket == null || !rightCurlyBracket.equals(RIGHT_CURLY_BRACKET)) throw new WrongJsonExpression(stream.getLine());			
+				} else {
+					// literal
+					paramTerm = new Constant(literalOrLeftCurlyBracket, DataTransferModel.typeString);
+				}
+				Type paramType = null;
+				if (paramTerm instanceof Variable) {
+					paramType = ((Variable) paramTerm).getType();
+				} else if (paramTerm instanceof Term) {
+					paramType = ((Term) paramTerm).getType();
+				}
+				Term term = null;
+				if (paramType != null && DataConstraintModel.typeInt.isAncestorOf(paramType)) {
+					term = new JsonAccessor(DataConstraintModel.dotParam);
+				} else {
+					term = new JsonAccessor(DataConstraintModel.dot);
+				}
+				term.addChild(exp);
+				term.addChild(paramTerm);
+				expressions.add(term);
+				operator = stream.checkNext();
+				if (operator == null || !operator.equals(DOT)) break;
 			} else {
 				break;
 			}
-			stream.next();		// an arithmetic operator
 		}
 		if (expressions.size() == 1) {
 			// no arithmetic operators
@@ -372,6 +411,23 @@
 		return firstMonomial;
 	}
 
+	private Variable parseVariable(TokenStream stream, DataTransferModel model, String symbolName) {
+		Variable var;
+		if (stream.checkNext() != null && stream.checkNext().equals(COLON)) {
+			// when a type is specified.
+			stream.next();
+			String typeName = stream.next();
+			Type type = model.getType(typeName);
+			if (type == null) {
+				type = new Type(typeName, typeName);
+			}
+			var = new Variable(symbolName, type);							
+		} else {
+			var = new Variable(symbolName);
+		}
+		return var;
+	}
+
 	/**--------------------------------------------------------------------------------
 	 * [protected]
 	/**--------------------------------------------------------------------------------
@@ -416,15 +472,18 @@
 																					splitBy(
 																							splitBy(
 																									splitBy(
-																											Arrays.asList(line.split("[ \t]")), 
-																											ADD,
-																											ADD_REGX),
-																									MUL,
-																									MUL_REGX),
-																							SUB,
-																							SUB_REGX),
-																					DIV,
-																					DIV_REGX),
+																											splitBy(
+																													Arrays.asList(line.split("[ \t]")), 
+																													ADD,
+																													ADD_REGX),
+																											MUL,
+																											MUL_REGX),
+																									SUB,
+																									SUB_REGX),
+																							DIV,
+																							DIV_REGX),
+																					DOT,
+																					DOT_REGX),
 																			COMMA, 
 																			COMMA),
 																	COLON, 
diff --git a/AlgebraicDataflowArchitectureModel/src/parser/ParserDTRAM.java b/AlgebraicDataflowArchitectureModel/src/parser/ParserDTRAM.java
index 54d0bf1..6330de2 100644
--- a/AlgebraicDataflowArchitectureModel/src/parser/ParserDTRAM.java
+++ b/AlgebraicDataflowArchitectureModel/src/parser/ParserDTRAM.java
@@ -27,6 +27,7 @@
 import parser.exceptions.ExpectedResource;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -62,9 +63,10 @@
 	/**--------------------------------------------------------------------------------
 	 * 
 	 * @param reader
+	 * @throws WrongJsonExpression 
 	 */
 	public DataTransferModel doParseModel() 
-			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment, ExpectedModel, ExpectedGeometry {
+			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment, ExpectedModel, ExpectedGeometry, WrongJsonExpression {
 		DataTransferModel model = getParsedModel();
 		return model;
 	}
@@ -84,9 +86,10 @@
 	/**--------------------------------------------------------------------------------
 	 * 
 	 * @param stream
+	 * @throws WrongJsonExpression 
 	 */
 	private DataTransferModel getParsedModel()
-			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment, ExpectedModel, ExpectedGeometry  {
+			throws ExpectedRightBracket, ExpectedChannel, ExpectedChannelName, ExpectedLeftCurlyBracket, ExpectedInOrOutOrRefKeyword, ExpectedStateTransition, ExpectedEquals, ExpectedRHSExpression, WrongLHSExpression, WrongRHSExpression, ExpectedAssignment, ExpectedModel, ExpectedGeometry, WrongJsonExpression  {
 
 		if (!stream.hasNext()) throw new NullPointerException();
 
diff --git a/AlgebraicDataflowArchitectureModel/src/parser/exceptions/WrongJsonExpression.java b/AlgebraicDataflowArchitectureModel/src/parser/exceptions/WrongJsonExpression.java
new file mode 100644
index 0000000..6a84d6f
--- /dev/null
+++ b/AlgebraicDataflowArchitectureModel/src/parser/exceptions/WrongJsonExpression.java
@@ -0,0 +1,9 @@
+package parser.exceptions;
+
+public class WrongJsonExpression extends ParseException {
+
+	public WrongJsonExpression(int line) {
+		super(line);
+	}
+
+}
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/CodeGeneratorTest.java b/AlgebraicDataflowArchitectureModel/src/tests/CodeGeneratorTest.java
index a89ea3c..54adfc7 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/CodeGeneratorTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/CodeGeneratorTest.java
@@ -23,6 +23,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -41,7 +42,7 @@
 				System.out.println(codetree);
 			} catch (ExpectedChannel | ExpectedChannelName | ExpectedLeftCurlyBracket | ExpectedInOrOutOrRefKeyword
 					| ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression | WrongLHSExpression
-					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment e) {
+					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment | WrongJsonExpression e) {
 				e.printStackTrace();
 			}
 		} catch (FileNotFoundException e) {
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/DataStorageDecisionTest.java b/AlgebraicDataflowArchitectureModel/src/tests/DataStorageDecisionTest.java
index 9d28936..e1cbbf4 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/DataStorageDecisionTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/DataStorageDecisionTest.java
@@ -19,6 +19,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -39,7 +40,7 @@
 				}
 			} catch (ExpectedChannel | ExpectedChannelName | ExpectedLeftCurlyBracket | ExpectedInOrOutOrRefKeyword
 					| ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression | WrongLHSExpression
-					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment e) {
+					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment | WrongJsonExpression e) {
 				e.printStackTrace();
 			}
 		} catch (FileNotFoundException e) {
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/DataStorageNecessityTest.java b/AlgebraicDataflowArchitectureModel/src/tests/DataStorageNecessityTest.java
index 9a7c300..7e9630d 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/DataStorageNecessityTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/DataStorageNecessityTest.java
@@ -18,6 +18,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -39,7 +40,7 @@
 				}
 			} catch (ExpectedChannel | ExpectedChannelName | ExpectedLeftCurlyBracket | ExpectedInOrOutOrRefKeyword
 					| ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression | WrongLHSExpression
-					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment e) {
+					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment | WrongJsonExpression e) {
 				e.printStackTrace();
 			}
 		} catch (FileNotFoundException e) {
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/EdgeTransitionSelectableTest.java b/AlgebraicDataflowArchitectureModel/src/tests/EdgeTransitionSelectableTest.java
index 847fb6f..df97097 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/EdgeTransitionSelectableTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/EdgeTransitionSelectableTest.java
@@ -18,6 +18,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -38,7 +39,7 @@
 				}
 			} catch (ExpectedChannel | ExpectedChannelName | ExpectedLeftCurlyBracket | ExpectedInOrOutOrRefKeyword
 					| ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression | WrongLHSExpression
-					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment e) {
+					| WrongRHSExpression | ExpectedRightBracket | ExpectedAssignment | WrongJsonExpression e) {
 				e.printStackTrace();
 			}
 		} catch (FileNotFoundException e) {
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/InverseTest.java b/AlgebraicDataflowArchitectureModel/src/tests/InverseTest.java
index 85644fc..c40de8a 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/InverseTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/InverseTest.java
@@ -16,10 +16,13 @@
 import models.algebra.Position;
 import models.algebra.Term;
 import models.algebra.Variable;
+import models.dataConstraintModel.DataConstraintModel;
+import models.dataConstraintModel.JsonType;
 import models.dataFlowModel.DataTransferModel;
 import parser.Parser;
 import parser.Parser.TokenStream;
 import parser.exceptions.ExpectedRightBracket;
+import parser.exceptions.WrongJsonExpression;
 
 public class InverseTest {
 	@Test
@@ -75,7 +78,7 @@
 			HashMap<Position, Variable> rhsVars3 = rhsExp3.getVariables();
 			for (Position vPos: rhsVars3.keySet()) {
 				Variable v = rhsVars3.get(vPos);
-				Expression inv = rhsExp3.getInverseMap(z, vPos);		// inverse map to get v back from the output value y
+				Expression inv = rhsExp3.getInverseMap(z, vPos);		// inverse map to get v back from the output value z
 				if (inv instanceof Term) {
 					inv = ((Term) inv).reduce();
 				}
@@ -83,7 +86,31 @@
 				assertFalse(inv.contains(v));
 				System.out.println(rhsVars3.get(vPos) + " = " + inv);
 			}			
-		} catch (ExpectedRightBracket e) {
+			
+			// Solve {z = x.id} for x
+			TokenStream stream4 = new Parser.TokenStream();
+			Parser parser4 = new Parser(stream4);
+			stream4.addLine("x.id");
+			Expression rhsExp4 = parser4.parseTerm(stream4, model);
+			System.out.println("=== solve{" + z + " = " + rhsExp4 + "} for x ===");
+			HashMap<Position, Variable> rhsVars4 = rhsExp4.getVariables();
+			for (Position vPos: rhsVars4.keySet()) {
+				Variable v = rhsVars4.get(vPos);
+				if (x.getName().equals("x")) {
+					JsonType jsonType = new JsonType("Json", "HashMap<>", DataConstraintModel.typeJson);
+					jsonType.addMemberType("id", DataConstraintModel.typeInt);
+					jsonType.addMemberType("name", DataConstraintModel.typeString);
+					v.setType(jsonType);
+				}
+				Expression inv = rhsExp4.getInverseMap(z, vPos);		// inverse map to get v back from the output value z
+				if (inv instanceof Term) {
+					inv = ((Term) inv).reduce();
+				}
+				System.out.println(rhsVars4.get(vPos) + " = " + inv);
+				assertTrue(inv.contains(z));
+				assertFalse(inv.contains(v));
+			}						
+		} catch (ExpectedRightBracket | WrongJsonExpression e) {
 			e.printStackTrace();
 		}
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/UpdateConflictCheckTest.java b/AlgebraicDataflowArchitectureModel/src/tests/UpdateConflictCheckTest.java
index 5f51af7..9ce5439 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/UpdateConflictCheckTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/UpdateConflictCheckTest.java
@@ -17,6 +17,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -61,6 +62,9 @@
 			} catch (ExpectedAssignment e) {
 				// TODO Auto-generated catch block
 				e.printStackTrace();
+			} catch (WrongJsonExpression e) {
+				// TODO Auto-generated catch block
+				e.printStackTrace();
 			}
 		} catch (FileNotFoundException e) {
 			e.printStackTrace();
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/parser/ParseTest.java b/AlgebraicDataflowArchitectureModel/src/tests/parser/ParseTest.java
index a1ea0a3..790d6ae 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/parser/ParseTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/parser/ParseTest.java
@@ -23,6 +23,7 @@
 import parser.exceptions.ExpectedRHSExpression;
 import parser.exceptions.ExpectedRightBracket;
 import parser.exceptions.ExpectedStateTransition;
+import parser.exceptions.WrongJsonExpression;
 import parser.exceptions.WrongLHSExpression;
 import parser.exceptions.WrongRHSExpression;
 
@@ -54,7 +55,7 @@
 					| ExpectedStateTransition | ExpectedEquals | ExpectedRHSExpression | WrongLHSExpression
 					| WrongRHSExpression | ExpectedRightBracket | ParameterizedIdentifierIsFutureWork 
 					| ResolvingMultipleDefinitionIsFutureWork | InvalidMessage
-					| UnificationFailed | ValueUndefined | ExpectedAssignment e) {
+					| UnificationFailed | ValueUndefined | ExpectedAssignment | WrongJsonExpression e) {
 				e.printStackTrace();
 			}
 		} catch (FileNotFoundException e) {