diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyCodeGenerator.java b/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyCodeGenerator.java
index 903c8f5..dfd8574 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyCodeGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyCodeGenerator.java
@@ -103,10 +103,14 @@
 					param.addAnnotation(new Annotation("FormParam", "\"" + srcName + "\""));
 					vars.add(param);
 					MethodDeclaration update = new MethodDeclaration("update" + srcResName, false, typeVoid, vars);
-					if (((StoreAttribute) rn.getAttribute()).isNeeded()) {
-						update.addAnnotation(new Annotation("POST"));
-					} else {
-						update.addAnnotation(new Annotation("PUT"));
+					for (ChannelMember cm: re.getChannelGenerator().getOutputChannelMembers()) {
+						if (cm.getIdentifierTemplate() == rn.getIdentifierTemplate()) {
+							if (cm.getStateTransition().isRightUnary()) {
+								update.addAnnotation(new Annotation("PUT"));
+							} else {
+								update.addAnnotation(new Annotation("POST"));
+							}
+						}
 					}
 					if (rn.getInEdges().size() > 1) {
 						 // For each source resource, a child resource is defined in the destination resource so that its state can be updated separately.
@@ -139,10 +143,10 @@
 							MethodDeclaration input = new MethodDeclaration(
 									((Term) cm.getStateTransition().getMessageExpression()).getSymbol().getImplName(),
 									false, typeVoid, params);
-							if (((StoreAttribute) rn.getAttribute()).isNeeded()) {
-								input.addAnnotation(new Annotation("POST"));
-							} else {
+							if (cm.getStateTransition().isRightUnary()) {
 								input.addAnnotation(new Annotation("PUT"));
+							} else {
+								input.addAnnotation(new Annotation("POST"));
 							}
 							type.addMethod(input);
 						}
diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java b/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java
index 42f4707..edc2624 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/JerseyMethodBodyGenerator.java
@@ -125,10 +125,10 @@
 							}
 							// src side (for a chain of update method invocations)
 							String httpMethod = null;
-							if (((StoreAttribute) dst.getAttribute()).isNeeded()) {
-								httpMethod = "post";
-							} else {
+							if (out.getStateTransition().isRightUnary()) {
 								httpMethod = "put";									
+							} else {
+								httpMethod = "post";
 							}
 							for (MethodDeclaration srcUpdate: getUpdateMethods(srcType)) {
 								if (srcUpdate != null) {
diff --git a/AlgebraicDataflowArchitectureModel/src/algorithms/NecessityOfStoringResourceStates.java b/AlgebraicDataflowArchitectureModel/src/algorithms/NecessityOfStoringResourceStates.java
index b533a79..35e5a9d 100644
--- a/AlgebraicDataflowArchitectureModel/src/algorithms/NecessityOfStoringResourceStates.java
+++ b/AlgebraicDataflowArchitectureModel/src/algorithms/NecessityOfStoringResourceStates.java
@@ -15,15 +15,7 @@
 		channels.addAll(model.getChannelGenerators());
 		for (ChannelGenerator generator: channels) {
 			for (ChannelMember member: ((DataflowChannelGenerator) generator).getOutputChannelMembers()) {
-				boolean flag = false;
-				Expression curexp = member.getStateTransition().getCurStateExpression();
-				Expression nextexp = member.getStateTransition().getNextStateExpression();
-				for (Position pos : curexp.getVariables().keySet()) {
-					if (nextexp.contains(curexp.getVariables().get(pos))) {
-						flag = true;
-						break;
-					}
-				}
+				boolean flag = !member.getStateTransition().isRightUnary();		// The state does not need to be stored if the state transition function is right unary.
 				for (Node node : graph.getNodes()) {
 					if (((ResourceNode) node).getIdentifierTemplate().equals(member.getIdentifierTemplate())) {
 						setStoreAttribute(flag, (ResourceNode) node);
diff --git a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/StateTransition.java b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/StateTransition.java
index 2bfb09b..cf41733 100644
--- a/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/StateTransition.java
+++ b/AlgebraicDataflowArchitectureModel/src/models/dataConstraintModel/StateTransition.java
@@ -40,6 +40,13 @@
 	public void setMessageExpression(Expression messageExpression) {
 		this.messageExpression = messageExpression;
 	}
+	
+	public boolean isRightUnary() {
+		for (Position pos : curStateExpression.getVariables().keySet()) {
+			if (nextStateExpression.contains(curStateExpression.getVariables().get(pos))) return false;
+		}
+		return true;
+	}
 
 	public Expression deriveMessageConstraintFor(Expression curStateValue, Expression nextStateValue) throws InvalidMessage, ResolvingMultipleDefinitionIsFutureWork {
 		HashMap<Variable, ArrayList<Expression>> bindings = new HashMap<>();