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AlgebraicDataflowArchitectureModel / AlgebraicDataflowArchitectureModel / src / generators / CodeGeneratorFromDataFlowGraph.java
package generators;

import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.AbstractMap.SimpleEntry;

import code.ast.Block;
import code.ast.CompilationUnit;
import code.ast.FieldDeclaration;
import code.ast.MethodDeclaration;
import code.ast.TypeDeclaration;
import code.ast.VariableDeclaration;
import models.Edge;
import models.Node;
import models.algebra.Constant;
import models.algebra.Expression;
import models.algebra.Field;
import models.algebra.InvalidMessage;
import models.algebra.ParameterizedIdentifierIsFutureWork;
import models.algebra.Position;
import models.algebra.Term;
import models.algebra.Type;
import models.algebra.UnificationFailed;
import models.algebra.ValueUndefined;
import models.algebra.Variable;
import models.dataConstraintModel.Channel;
import models.dataConstraintModel.ChannelMember;
import models.dataConstraintModel.DataConstraintModel;
import models.dataConstraintModel.JsonAccessor;
import models.dataConstraintModel.ResourceHierarchy;
import models.dataConstraintModel.ResourcePath;
import models.dataConstraintModel.Selector;
import models.dataFlowModel.DataFlowEdge;
import models.dataFlowModel.DataFlowGraph;
import models.dataFlowModel.DataTransferChannel;
import models.dataFlowModel.DataTransferModel;
import models.dataFlowModel.PushPullAttribute;
import models.dataFlowModel.PushPullValue;
import models.dataFlowModel.ResolvingMultipleDefinitionIsFutureWork;
import models.dataFlowModel.ResourceNode;
import models.dataFlowModel.ChannelNode;
import models.dataFlowModel.StoreAttribute;
import models.dataFlowModel.DataTransferChannel.IResourceStateAccessor;

public class CodeGeneratorFromDataFlowGraph extends CodeGenerator {

	public void generateCodeFromFlowGraph(DataTransferModel model, DataFlowGraph flowGraph, ArrayList<ResourceNode> components, Map<ResourceHierarchy, Set<ResourceHierarchy>> dependedRootComponentGraph, 
			TypeDeclaration mainComponent, MethodDeclaration mainConstructor, ArrayList<CompilationUnit> codes, ILanguageSpecific langSpec) {
		Map<ResourceHierarchy, TypeDeclaration> resourceComponents = new HashMap<>();
		Map<ResourceHierarchy, MethodDeclaration> resourceConstructors = new HashMap<>();
		List<Map.Entry<ResourceHierarchy, VariableDeclaration>> constructorParams = new ArrayList<>();
		List<Map.Entry<ResourceHierarchy, String>> constructorStatements = new ArrayList<>();
		Map<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>> updateStatements = new HashMap<>();
		
		// For each components (1st pass).
		for (Node componentNode: components) {
			ResourceNode resourceNode = (ResourceNode) componentNode;
			TypeDeclaration component = null;
			if (generatesComponent(resourceNode.getResourceHierarchy())) {
				// A component will be generated for this resource.
				String resourceName = getComponentName(resourceNode.getResourceHierarchy(), langSpec);
				component = resourceComponents.get(resourceNode.getResourceHierarchy());
				List<ResourceHierarchy> depends = new ArrayList<>();
				if (component == null) {
					// Add compilation unit for this component.
					component = langSpec.newTypeDeclaration(resourceName);
					resourceComponents.put(resourceNode.getResourceHierarchy(), component);
					CompilationUnit cu = langSpec.newCompilationUnit(component);
					codes.add(cu);
					
					// Declare the constructor and the fields to refer to other resources.
					MethodDeclaration constructor = declareConstructorAndFieldsToReferToResources(resourceNode, component, dependedRootComponentGraph, depends, langSpec);
					
					if (resourceNode.getResourceHierarchy().getParent() == null) {
						// For each root resource
						// Update the main component for this component.
						updateMainComponent(model, mainComponent, mainConstructor, componentNode, depends, langSpec);
					}
					
					// Declare the fields to refer to reference resources.
					declareFieldsToReferenceResources(model, resourceNode, component, constructor, depends, langSpec);				
					
					if (constructor.getParameters() == null) {
						component.removeMethod(constructor);
					} else {
						resourceConstructors.put(resourceNode.getResourceHierarchy(), constructor);						
					}
				}
			}
		}
		
		// For each components (2nd pass).
		for (Node componentNode: components) {
			// Declare this resource.
			ResourceNode resourceNode = (ResourceNode) componentNode;
			Type resStateType = getImplStateType(resourceNode.getResourceHierarchy(), langSpec);
			TypeDeclaration component = null;
			TypeDeclaration parentComponent = null;
			if (generatesComponent(resourceNode.getResourceHierarchy())) {
				String resourceName = getComponentName(resourceNode.getResourceHierarchy(), langSpec);
				component = resourceComponents.get(resourceNode.getResourceHierarchy());
				
				// Declare the field in this resource to store the state.
				if (((StoreAttribute) resourceNode.getAttribute()).isStored()) {
					declareStateField(resourceNode, resourceName, component, resStateType, constructorParams, langSpec);
				}
				
				// Declare the getter methods in this resource to obtain the children resources.
				declareChildGetterMethod(resourceNode, component, langSpec);
			}
			if (resourceNode.getResourceHierarchy().getParent() != null) {
				parentComponent = resourceComponents.get(resourceNode.getResourceHierarchy().getParent());
			}
			
			// Declare cache fields and update methods in this resource.
			Map.Entry<List<String>, Map<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>>> initStatementsAndUpdateUpdates = declareCacheFieldsAndUpdateMethods(resourceNode, component, parentComponent, langSpec);
			if (component == null) {
				// Constructor statements were not added to any component because no component had been generated.
				for (String statement: initStatementsAndUpdateUpdates.getKey()) {
					constructorStatements.add(new AbstractMap.SimpleEntry<>(resourceNode.getResourceHierarchy().getParent(), statement));
				}
			}
			for (Map.Entry<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>> entry: initStatementsAndUpdateUpdates.getValue().entrySet()) {
				updateStatements.put(entry.getKey(), entry.getValue());
			}
			
			// Declare the state field and reference fields in the parent component.
			if (component == null) {
				declareFieldsInParentComponent(resourceNode, parentComponent, constructorParams, langSpec);
			}
			
			// Declare the getter method in this resource to obtain the state.
			MethodDeclaration stateGetter = declareStateGetterMethod(resourceNode, component, parentComponent, resStateType, langSpec);
			
			// Declare the accessor method in the main component to call the getter method.
			declareAccessorInMainComponent(mainComponent, resourceNode, stateGetter, langSpec);
			
			// Declare input methods in this component and the main component.
			Map.Entry<List<String>, Map<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>>> initStatementsAndInputUpdates = declareInputMethodsInThisAndMainComponents(resourceNode, component, parentComponent, mainComponent, model, langSpec);
			if (component == null) {
				// Constructor statements were not added to any component because no component had been generated.
				for (String statement: initStatementsAndInputUpdates.getKey()) {
					constructorStatements.add(new AbstractMap.SimpleEntry<>(resourceNode.getResourceHierarchy().getParent(), statement));
				}
			}
			for (Map.Entry<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>> entry: initStatementsAndInputUpdates.getValue().entrySet()) {
				updateStatements.put(entry.getKey(), entry.getValue());
			}
		}
		
		// Add constructor parameters to the ancestor components.
		for (ResourceNode root: flowGraph.getRootResourceNodes()) {
			addConstructorParameters(root.getResourceHierarchy(), resourceComponents, resourceConstructors, constructorParams, langSpec);
		}
		
		// Add constructor statements.
		for (Map.Entry<ResourceHierarchy, String> entry: constructorStatements) {
			resourceConstructors.get(entry.getKey()).addStatement(entry.getValue());
		}
		
		// Add update statements.
		for (MethodDeclaration method: updateStatements.keySet()) {
			Expression updateExp = updateStatements.get(method).getKey();
			ResourceHierarchy childRes = updateStatements.get(method).getValue();
			TypeDeclaration childComponent = resourceComponents.get(childRes);
			addUpdateStatementWithConstructorInvocationToMethod(method, updateExp, childRes, childComponent, langSpec);
		}
	}

	private static List<VariableDeclaration> addConstructorParameters(ResourceHierarchy resource, Map<ResourceHierarchy, TypeDeclaration> resourceComponents,
			Map<ResourceHierarchy, MethodDeclaration> resourceConstructors, List<Entry<ResourceHierarchy, VariableDeclaration>> constructorParams, ILanguageSpecific langSpec) {
		List<VariableDeclaration> params = new ArrayList<>();
		for (ResourceHierarchy child: resource.getChildren()) {
			params.addAll(addConstructorParameters(child, resourceComponents, resourceConstructors, constructorParams, langSpec));
		}
		for (Entry<ResourceHierarchy, VariableDeclaration> paramEnt: constructorParams) {
			if (paramEnt.getKey().equals(resource)) {
				params.add(paramEnt.getValue());
			}
		}
		if (params.size() > 0) {
			MethodDeclaration constructor = resourceConstructors.get(resource);
			if (constructor == null) {
				if (resourceComponents.get(resource) != null) {
					String resourceName = getComponentName(resource, langSpec);
					constructor = new MethodDeclaration(resourceName, true);
					Block body = new Block();
					constructor.setBody(body);
					resourceComponents.get(resource).addMethod(constructor);
					resourceConstructors.put(resource, constructor);
				}
			}
			if (constructor != null) {
				for (VariableDeclaration param: params) {
					constructor.addParameter(param);
					constructor.getBody().addStatement(langSpec.getFieldAccessor(langSpec.toVariableName(param.getName())) + langSpec.getAssignment() + langSpec.toVariableName(param.getName()) + langSpec.getStatementDelimiter());
				}
			}
		}
		if (resource.getNumParameters() > 0) params.clear();
		return params;
	}
	
	private void addUpdateStatementWithConstructorInvocationToMethod(MethodDeclaration method, Expression exp, ResourceHierarchy childRes, TypeDeclaration childComponent, ILanguageSpecific langSpec) {
		Type replacedJsonType = childRes.getResourceStateType();
		String replacingClassName = getComponentName(childRes, langSpec);
		Map<Position, Term> subTerms = ((Term) exp).getSubTerms(Term.class);
		for (Entry<Position, Term> termEnt: subTerms.entrySet()) {
			Term jsonTerm = termEnt.getValue();
			if (jsonTerm.getType().equals(replacedJsonType)) {
				MethodDeclaration childConstructor = getConstructor(childComponent);
				List<String> params = new ArrayList<>();
				for (VariableDeclaration var: childConstructor.getParameters()) {
					JsonAccessor jsonMember = new JsonAccessor(DataConstraintModel.dot);
					jsonMember.addChild(jsonTerm);
					jsonMember.addChild(new Constant("\"" + var.getName() + "\""));
					Expression param = jsonMember.reduce();
					if (param != null) {
						params.add(param.toImplementation(new String[] {""}));
					} else {
						params.add(var.getName());
					}
				}
				((Term) exp).replaceSubTerm(termEnt.getKey(), new Constant(langSpec.getConstructorInvocation(replacingClassName, params)));
			}
		}
		String[] sideEffects = new String[] {""};
		String newState = exp.toImplementation(sideEffects);
		String updateStatement;
		if (exp instanceof Term && ((Term) exp).getSymbol().isImplWithSideEffect()) {
			updateStatement = sideEffects[0];	
		} else {
			updateStatement = sideEffects[0] + langSpec.getFieldAccessor(fieldOfResourceState) + langSpec.getAssignment() + newState + langSpec.getStatementDelimiter();
		}
		method.addFirstStatement(updateStatement);
	}

	private MethodDeclaration declareConstructorAndFieldsToReferToResources(ResourceNode resourceNode, TypeDeclaration component, Map<ResourceHierarchy, Set<ResourceHierarchy>> dependedRootComponentGraph, 
			List<ResourceHierarchy> depends, ILanguageSpecific langSpec) {
		// Declare a constructor in each component.
		MethodDeclaration constructor = component.createConstructor();
		Block block = new Block();
		constructor.setBody(block);
		
		// Declare fields in each component. (for data-flow graph)
		for (Edge resToCh: resourceNode.getOutEdges()) {
			DataTransferChannel ch = ((ChannelNode) resToCh.getDestination()).getChannel();
			// Check if the input resource is outside of the channel scope.
			boolean outsideInputResource = false;
			for (ChannelMember cm: ch.getInputChannelMembers()) {
				if (cm.getResource().getResourceHierarchy().equals(resourceNode.getResourceHierarchy()) && cm.isOutside()) {
					outsideInputResource = true;	// Regarded as pull transfer.
					break;
				}
			}
			// Check if the output resource is outside of the channel scope.
			boolean outsideOutputResource = false;
			for (ChannelMember cm: ch.getOutputChannelMembers()) {
				if (cm.getResource().getResourceHierarchy().equals(resourceNode.getOutSideResource().getResourceHierarchy()) && cm.isOutside()) {
					outsideOutputResource = true;	// Regarded as push transfer.
					break;
				}
			}
			if (((PushPullAttribute) ((DataFlowEdge) resToCh).getAttribute()).getOptions().get(0) == PushPullValue.PUSH && !outsideInputResource) {
				for (Edge chToRes: resToCh.getDestination().getOutEdges()) {
					// for PUSH transfer
					if (chToRes.getDestination() instanceof ResourceNode) {
						ResourceHierarchy dstRes = addReference(component, constructor, ((ResourceNode) chToRes.getDestination()).getOutSideResource().getResourceHierarchy(), langSpec);
						if (outsideOutputResource) {
							if (dstRes != null && dstRes.getParent() != null) {
								// Reference to root resource.
								addReference(component, constructor, dstRes.getRoot(), langSpec);
							}
						}
						if (!depends.contains(dstRes)) depends.add(dstRes);
					}
				}
			}
		}
		for (Edge chToRes: resourceNode.getInEdges()) {
			for (Edge resToCh: chToRes.getSource().getInEdges()) {
				ResourceHierarchy srcRes = ((ResourceNode) resToCh.getSource()).getOutSideResource().getResourceHierarchy();
				DataTransferChannel ch = ((ChannelNode) resToCh.getDestination()).getChannel();
				// Check if the input resource is outside of the channel scope.
				boolean outsideInputResource = false;
				for (ChannelMember cm: ch.getInputChannelMembers()) {
					if (cm.getResource().getResourceHierarchy().equals(srcRes) && cm.isOutside()) {
						outsideInputResource = true;	// Regarded as pull transfer.
						break;
					}
				}
				// Check if the output resource is outside of the channel scope.
				boolean outsideOutputResource = false;
				for (ChannelMember cm: ch.getOutputChannelMembers()) {
					if (cm.getResource().getResourceHierarchy().equals(resourceNode.getOutSideResource().getResourceHierarchy()) && cm.isOutside()) {
						outsideOutputResource = true;	// Regarded as push transfer.
						break;
					}
				}
				if ((((PushPullAttribute) ((DataFlowEdge) resToCh).getAttribute()).getOptions().get(0) != PushPullValue.PUSH && !outsideOutputResource) || outsideInputResource) {
					// for PULL transfer
					srcRes = addReference(component, constructor, ((ResourceNode) resToCh.getSource()).getOutSideResource().getResourceHierarchy(), langSpec);
					if (outsideInputResource) {
						if (srcRes != null & srcRes.getParent() != null) {
							// Reference to root resource.
							addReference(component, constructor, srcRes.getRoot(), langSpec);
						}
					}
					if (!depends.contains(srcRes)) depends.add(srcRes);
				}
			}
		}
		// Declare a field to refer to outside resources.
		if (resourceNode.getParent() == null) {
			for (ResourceHierarchy dependedRes: dependedRootComponentGraph.keySet()) {
				for (ResourceHierarchy dependingRes: dependedRootComponentGraph.get(dependedRes)) {
					if (resourceNode.getResourceHierarchy().equals(dependingRes)) {
						// Declare a field to refer to outside resources.
						depends.add(dependedRes);
						addReference(component, constructor, dependedRes, langSpec);
					}
				}
			}
		}
		return constructor;
	}
	
	private void declareStateField(ResourceNode resourceNode, String resourceName, TypeDeclaration component, Type resStateType, List<Map.Entry<ResourceHierarchy, VariableDeclaration>> constructorParams, ILanguageSpecific langSpec) {
		Set<ResourceHierarchy> children = resourceNode.getResourceHierarchy().getChildren();
		if (children == null || children.size() == 0) {
			// leaf resource.
			FieldDeclaration stateField = langSpec.newFieldDeclaration(resStateType, fieldOfResourceState, langSpec.getFieldInitializer(resStateType, resourceNode.getResourceHierarchy().getInitialValue()));
			component.addField(stateField);
			constructorParams.add(new AbstractMap.SimpleEntry<>(resourceNode.getResourceHierarchy(), langSpec.newVariableDeclaration(resStateType, langSpec.toVariableName(resourceName))));
		} else {
			ResourceHierarchy child = children.iterator().next();
			if (children.size() == 1 && child.getNumParameters() > 0) {
				// map or list.
				FieldDeclaration stateField = langSpec.newFieldDeclaration(resStateType, fieldOfResourceState, langSpec.getFieldInitializer(resStateType, resourceNode.getResourceHierarchy().getInitialValue()));
				component.addField(stateField);
			} else {
				// class
				for (ResourceHierarchy c: children) {
					String childTypeName = getComponentName(c, langSpec);
					Type childType = null;
					if (generatesComponent(c)) {
						// The child has a component.
						childType = new Type(childTypeName, childTypeName);
						String fieldName = langSpec.toVariableName(childTypeName);
						FieldDeclaration stateField = langSpec.newFieldDeclaration(childType, fieldName, langSpec.getFieldInitializer(resStateType, resourceNode.getResourceHierarchy().getInitialValue()));
						component.addField(stateField);
					}
				}
			}
		}
	}

	private void declareFieldsInParentComponent(ResourceNode resourceNode, TypeDeclaration parentComponent, List<Map.Entry<ResourceHierarchy, VariableDeclaration>> constructorParams, ILanguageSpecific langSpec) {
		// Declare reference fields for push/pull data transfer.
		boolean noPullTransfer = true;
		for (Edge resToCh : resourceNode.getOutEdges()) {
			DataFlowEdge re = (DataFlowEdge) resToCh;
			DataTransferChannel ch = ((ChannelNode) re.getDestination()).getChannel();
			for (Edge chToRes: re.getDestination().getOutEdges()) {
				ResourcePath dstRes = ((ResourceNode) chToRes.getDestination()).getOutSideResource();
				// Check if the destination resource is outside of the channel scope.
				boolean outsideOutputResource = false;
				for (ChannelMember cm: ch.getOutputChannelMembers()) {
					if (cm.getResource().getResourceHierarchy().equals(dstRes.getResourceHierarchy()) && cm.isOutside()) {
						outsideOutputResource = true;	// Regarded as push transfer.
						break;
					}
				}
				if (outsideOutputResource) {
					// Declare a field in the parent component to refer to the destination resource of push transfer.
					String dstResName = null;
					if (!generatesComponent(dstRes.getResourceHierarchy())) {
						dstRes = dstRes.getParent();
					}
					dstResName = getComponentName(dstRes.getResourceHierarchy(), langSpec);
					FieldDeclaration refFieldForPush = langSpec.newFieldDeclaration(new Type(dstResName, dstResName), langSpec.toVariableName(dstResName));
					parentComponent.addField(refFieldForPush);
					if (dstRes.getParent() != null) {
						// Reference to root resource.
						String dstRootResName = getComponentName(dstRes.getRoot().getResourceHierarchy(), langSpec);
						Type dstRootResType = new Type(dstRootResName, dstRootResName);
						dstRootResName = langSpec.toVariableName(dstRootResName);
						FieldDeclaration refRootFieldForPush = langSpec.newFieldDeclaration(dstRootResType, dstRootResName);
						parentComponent.addField(refRootFieldForPush);
						constructorParams.add(new AbstractMap.SimpleEntry<>(resourceNode.getParent().getResourceHierarchy(), langSpec.newVariableDeclaration(dstRootResType, dstRootResName)));
					}
				}
			}
		}
		for (Edge chToRes : resourceNode.getInEdges()) {
			for (Edge resToCh: chToRes.getSource().getInEdges()) {
				DataFlowEdge re = (DataFlowEdge) resToCh;
				ResourcePath srcRes = ((ResourceNode) re.getSource()).getOutSideResource();
				DataTransferChannel ch = ((ChannelNode) re.getDestination()).getChannel();
				// Check if the source resource is outside of the channel scope.
				boolean outsideInputResource = false;
				for (ChannelMember cm: ch.getInputChannelMembers()) {
					if (cm.getResource().getResourceHierarchy().equals(srcRes.getResourceHierarchy()) && cm.isOutside()) {
						outsideInputResource = true;	// Regarded as pull transfer.
						break;
					}
				}
				if (outsideInputResource) {
					// Declare a field in the parent component to refer to the source resource of pull transfer.
					String srcResName = null;
					if (!generatesComponent(srcRes.getResourceHierarchy())) {
						srcRes = srcRes.getParent();
					}
					srcResName = getComponentName(srcRes.getResourceHierarchy(), langSpec);
					FieldDeclaration refFieldForPull = langSpec.newFieldDeclaration(new Type(srcResName, srcResName), langSpec.toVariableName(srcResName));
					parentComponent.addField(refFieldForPull);
					if (srcRes.getParent() != null) {
						// Reference to root resource.
						String srcRootResName = getComponentName(srcRes.getRoot().getResourceHierarchy(), langSpec);
						Type srcRootResType = new Type(srcRootResName, srcRootResName);
						srcRootResName = langSpec.toVariableName(srcRootResName);
						FieldDeclaration refRootFieldForPull = langSpec.newFieldDeclaration(srcRootResType, srcRootResName);
						parentComponent.addField(refRootFieldForPull);
						constructorParams.add(new AbstractMap.SimpleEntry<>(resourceNode.getParent().getResourceHierarchy(), langSpec.newVariableDeclaration(srcRootResType, srcRootResName)));
					}
					noPullTransfer = false;
				}
			}
		}
		// Declare the state field in the parent component.
		ResourceHierarchy res = resourceNode.getOutSideResource().getResourceHierarchy();
		if (((StoreAttribute) resourceNode.getAttribute()).isStored() && noPullTransfer && res.getNumParameters() == 0) {
			String resName = getComponentName(res, langSpec);
			FieldDeclaration stateField = langSpec.newFieldDeclaration(res.getResourceStateType(), langSpec.toVariableName(resName));
			parentComponent.addField(stateField);
			constructorParams.add(new AbstractMap.SimpleEntry<>(resourceNode.getParent().getResourceHierarchy(), langSpec.newVariableDeclaration(res.getResourceStateType(), langSpec.toVariableName(resName))));
		}
	}
	
	private MethodDeclaration declareStateGetterMethod(ResourceNode resourceNode, TypeDeclaration component, TypeDeclaration parentComponent, Type resStateType, ILanguageSpecific langSpec) {
		// Declare the getter method of the resource state.
		MethodDeclaration stateGetter = null;
		if (component != null) {
			// A component is created for this resource.
			stateGetter = langSpec.newMethodDeclaration(getterOfResourceState, resStateType);
			component.addMethod(stateGetter);
		} else {
			// No component is created for this resource.			
			List<VariableDeclaration> getterParams = new ArrayList<>();
			int v = 1;
			for (Selector param: resourceNode.getSelectors()) {
				if (param.getExpression() instanceof Variable) {
					Variable var = (Variable) param.getExpression();
					getterParams.add(new VariableDeclaration(var.getType(), var.getName()));
				} else if (param.getExpression() instanceof Term) {
					Term var = (Term) param.getExpression();
					getterParams.add(new VariableDeclaration(var.getType(), "v" + v));
				}
				v++;
			}
			String resCompName = getComponentName(resourceNode.getResourceHierarchy(), langSpec);
			if (getterParams.size() == 0) {
				stateGetter = new MethodDeclaration(getterPrefix + resCompName, resStateType);
			} else {
				stateGetter = new MethodDeclaration(getterPrefix + resCompName, false, resStateType, getterParams);
			}
			if (parentComponent != null) {
				parentComponent.addMethod(stateGetter);
			}
		}
		
		if (((StoreAttribute) resourceNode.getAttribute()).isStored()) {
			if (component != null) {
				// A component is created for this resource.
				fillStateGetterMethod(stateGetter, resourceNode.getResourceHierarchy(), resStateType, langSpec);
			} else {
				// No component is created for this resource.			
				fillChildGetterMethod(stateGetter, resourceNode.getResourceHierarchy(), resourceNode.getResourceHierarchy().getParent().getResourceStateType(), langSpec);
			}
		} else {	
			// invocations to other getter methods when at least one incoming data-flow edges is PULL-style.
			boolean isContainedPush = false;
			DataTransferChannel ch = null;
			HashMap<ChannelMember, IResourceStateAccessor> inputResourceToStateAccessor = new HashMap<>();
			for (Edge chToRes: resourceNode.getInEdges()) {
				DataTransferChannel ch2 = ((ChannelNode) chToRes.getSource()).getChannel();
				for (Edge resToCh: chToRes.getSource().getInEdges()) {
					DataFlowEdge dIn = (DataFlowEdge) resToCh;
					ChannelMember in = null;
					for (ChannelMember cm: ch2.getInputChannelMembers()) {
						if (cm.getResource().equals(((ResourceNode) dIn.getSource()).getOutSideResource())) {
							in = cm;
							break;
						}
					}
					if (((PushPullAttribute) dIn.getAttribute()).getOptions().get(0) == PushPullValue.PUSH) {
						// PUSH transfer
						isContainedPush = true;
						inputResourceToStateAccessor.put(in, getPushAccessor());
					} else {
						// PULL transfer
						inputResourceToStateAccessor.put(in, getPullAccessor());
						ch = ((ChannelNode) resToCh.getDestination()).getChannel();		// pull containing input side channel is always one.
					}
				}
			}
			// for reference channel members.
			for (ChannelMember c: ch.getReferenceChannelMembers()) {
				inputResourceToStateAccessor.put(c, getPullAccessor());			// by pull data transfer
			}
			
			// generate a return statement.
			try {
				for (ChannelMember out: ch.getOutputChannelMembers()) {
					if (resourceNode.getInSideResources().contains(out.getResource())) {
						String[] sideEffects = new String[] {""};
						if (!isContainedPush) {
							// All incoming edges are in PULL-style.
							String curState = ch.deriveUpdateExpressionOf(out, getPullAccessor()).toImplementation(sideEffects);
							stateGetter.addStatement(sideEffects[0] + langSpec.getReturnStatement(curState) + langSpec.getStatementDelimiter());
						} else {
							// At least one incoming edge is in PUSH-style.
							String curState = ch.deriveUpdateExpressionOf(out, getPullAccessor(), inputResourceToStateAccessor).toImplementation(sideEffects);
							stateGetter.addStatement(sideEffects[0] + langSpec.getReturnStatement(curState) + langSpec.getStatementDelimiter());
						}
						break;
					}
				}
			} catch (ParameterizedIdentifierIsFutureWork | ResolvingMultipleDefinitionIsFutureWork
					| InvalidMessage | UnificationFailed | ValueUndefined e) {
				e.printStackTrace();
			}
		}
		
		return stateGetter;
	}
	
	private void declareChildGetterMethod(ResourceNode resourceNode, TypeDeclaration component, ILanguageSpecific langSpec) {
		// Declare the getter methods in this resource to obtain the children resources.
		for (ResourceNode child: resourceNode.getChildren()) {
			if (generatesComponent(child.getResourceHierarchy())) {
				// A component for the child is generated.
				List<VariableDeclaration> params = new ArrayList<>();
				int v = 1;
				for (Selector param: child.getSelectors()) {
					if (param.getExpression() instanceof Variable) {
						Variable var = (Variable) param.getExpression();
						params.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));
					} else if (param.getExpression() instanceof Term) {
						Term var = (Term) param.getExpression();
						params.add(langSpec.newVariableDeclaration(var.getType(), "v" + v));
					}
					v++;
				}
				String childCompName = getComponentName(child.getResourceHierarchy(), langSpec);
				Type childType = new Type(childCompName, childCompName);
				MethodDeclaration childGetter = null;
				if (params.size() == 0) {
					childGetter = langSpec.newMethodDeclaration(getterPrefix + childCompName, childType);
				} else {
					childGetter = langSpec.newMethodDeclaration(getterPrefix + childCompName, false, childType, params);
				}
				
				fillChildGetterMethod(childGetter, child.getResourceHierarchy(), resourceNode.getResourceStateType(), langSpec);
				component.addMethod(childGetter);
			}
		}
	}
	
	private Map.Entry<List<String>, Map<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>>> declareCacheFieldsAndUpdateMethods(ResourceNode resourceNode, TypeDeclaration component, TypeDeclaration parentComponent, ILanguageSpecific langSpec) {
		// Declare cash fields and update methods in the component.
		String resComponentName = langSpec.toComponentName(resourceNode.getResourceName());
		List<String> constructorStatements = new ArrayList<>();
		Map<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>> updateStatements = new HashMap<>();
		for (Edge chToRes: resourceNode.getInEdges()) {
			for (Edge resToCh: chToRes.getSource().getInEdges()) {
				DataTransferChannel ch = ((ChannelNode) resToCh.getDestination()).getChannel();
				DataFlowEdge re = (DataFlowEdge) resToCh;
				ResourcePath srcRes = ((ResourceNode) re.getSource()).getOutSideResource();
				String srcResName = srcRes.getResourceName();
				String srcResComponentName = langSpec.toComponentName(srcResName);
				// Check if the input resource is outside of the channel scope.
				boolean outsideInputResource = false;
				for (ChannelMember cm: ch.getInputChannelMembers()) {
					if (cm.getResource().getResourceHierarchy().equals(srcRes.getResourceHierarchy()) && cm.isOutside()) {
						outsideInputResource = true;	// Regarded as pull transfer.
						break;
					}
				}
				if (((PushPullAttribute) re.getAttribute()).getOptions().get(0) == PushPullValue.PUSH && !outsideInputResource) {
					// for push data transfer
					
					// Declare an update method in the type of the destination resource.
					ArrayList<VariableDeclaration> vars = new ArrayList<>();
					vars.add(langSpec.newVariableDeclaration(srcRes.getResourceStateType(), srcRes.getResourceName()));				
					// For the refs.
					for (ResourcePath ref: ch.getReferenceResources()) {
						if (!resourceNode.getInSideResources().contains(ref)) {
							vars.add(langSpec.newVariableDeclaration(ref.getResourceStateType(), ref.getResourceName()));
						}
					}
					MethodDeclaration update = langSpec.newMethodDeclaration(updateMethodName + srcResComponentName, false, null, vars);
					if (component != null) {
						component.addMethod(update);
					} else if (parentComponent != null) {
						parentComponent.addMethod(update);
					}
					
					// Add a statement to update the state field
					if (((StoreAttribute) resourceNode.getAttribute()).isStored()) {
						try {
							for (ChannelMember out: ch.getOutputChannelMembers()) {
								if (resourceNode.getInSideResources().contains(out.getResource())) {
									Expression updateExp = ch.deriveUpdateExpressionOf(out, getPushAccessor());
									// Replace Json constructor with a constructor of the child resource.
									ResourceHierarchy outRes = out.getResource().getResourceHierarchy();
									if (outRes.getChildren().size() == 1 && outRes.getChildren().iterator().next().getNumParameters() > 0) {
										ResourceHierarchy childRes = outRes.getChildren().iterator().next();
										Type childStateType = childRes.getResourceStateType();
										if (DataConstraintModel.typeJson.isAncestorOf(childStateType)) {
											updateStatements.put(update, new AbstractMap.SimpleEntry<>(updateExp, childRes));
											break;
										}
									}
									// Add statements to the input method.
									String[] sideEffects = new String[] {""};
									String curState = updateExp.toImplementation(sideEffects);
									String updateStatement;
									if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
										updateStatement = sideEffects[0];
									} else {
										updateStatement = sideEffects[0] + langSpec.getFieldAccessor(fieldOfResourceState) + langSpec.getAssignment() + curState + langSpec.getStatementDelimiter();	// this.value = ...
									}
									if (update.getBody() == null || !update.getBody().getStatements().contains(updateStatement)) {
										update.addFirstStatement(updateStatement);
									}							
									break;
								}
							}
						} catch (ParameterizedIdentifierIsFutureWork | ResolvingMultipleDefinitionIsFutureWork
								| InvalidMessage | UnificationFailed | ValueUndefined e1) {
							e1.printStackTrace();
						}
					}
					
					// Declare the field to cache the state of the source resource in the type of the destination resource.
					if (resToCh.getDestination().getIndegree() > 1) {
						// If incoming edges are multiple
						if (langSpec.declareField()) {
							// Declare the cache field. 
							FieldDeclaration cacheField = langSpec.newFieldDeclaration(
																	srcRes.getResourceStateType(), 
																	srcRes.getResourceName(), 
																	langSpec.getFieldInitializer(srcRes.getResourceStateType(), srcRes.getResourceHierarchy().getInitialValue()));
							if (component != null) {
								component.addField(cacheField);
							} else if (parentComponent != null){
								parentComponent.addField(cacheField);
							}
							
						}
						// Update the cache field.
						String cashStatement = langSpec.getFieldAccessor(langSpec.toVariableName(srcResName)) + langSpec.getAssignment() + langSpec.toVariableName(srcResName) + langSpec.getStatementDelimiter();
						if (update.getBody() == null || !update.getBody().getStatements().contains(cashStatement)) {
							update.addFirstStatement(cashStatement);
						}
					}
					
					Set<ChannelMember> outsideInputMembers = new HashSet<>();
					for (ChannelMember cm: ch.getInputChannelMembers()) {
						if (cm.isOutside()) {
							outsideInputMembers.add(cm);
						}
					}
					if (outsideInputMembers.size() > 0) {
						Map<ChannelMember, Entry<ResourcePath, Set<ChannelMember>>> resourcePaths = null;
						for (ChannelMember out: ch.getOutputChannelMembers()) {
							if (resourceNode.getInSideResources().contains(out.getResource())) {
								try {
									resourcePaths = ch.fillOutsideResourcePaths(out, getPullAccessor());
								} catch (ParameterizedIdentifierIsFutureWork | ResolvingMultipleDefinitionIsFutureWork
										| InvalidMessage | UnificationFailed | ValueUndefined e) {
									e.printStackTrace();
								}
								break;
							}
						}
						if (resourcePaths != null && resourcePaths.size() > 0) {
							for (ChannelMember outsideMember: outsideInputMembers) {
								for (ChannelMember dependingMember: resourcePaths.get(outsideMember).getValue()) {
									if (dependingMember.getResource().equals(srcRes)) {
										// An outside input resource path depends on srcRes.
										ResourcePath outsidePath = resourcePaths.get(outsideMember).getKey();
										String outsideResName = langSpec.toVariableName(getComponentName(outsidePath.getResourceHierarchy(), langSpec));
										Expression outsideExp = getPullAccessor().getDirectStateAccessorFor(outsidePath, null);
										if (generatesComponent(outsidePath.getResourceHierarchy())) {
											outsideExp = ((Term) outsideExp).getChild(0);
										}
										Expression nextExp = dependingMember.getStateTransition().getNextStateExpression();
										if (nextExp != null && outsideExp instanceof Term) {
											if (nextExp instanceof Variable) {
												outsideExp = ((Term) outsideExp).substitute((Variable) nextExp, new Field(langSpec.toVariableName(getComponentName(dependingMember.getResource().getResourceHierarchy(), langSpec)))); 
											} else {
												// ToDo.
											}
										}
										String[] sideEffects = new String[] {""};
										String outsideAccessor = outsideExp.toImplementation(sideEffects);
										String updateReference = langSpec.getFieldAccessor(outsideResName) + langSpec.getAssignment() + outsideAccessor + langSpec.getStatementDelimiter();
										update.addStatement(updateReference);			// Update the reference field.
										// Update constructor.
										if (component != null) {
											MethodDeclaration constructor = getConstructor(component);
											constructor.addStatement(updateReference);		// Initialize the reference field.
										} else if (parentComponent != null){
											constructorStatements.add(updateReference);
										}
									}
								}
							}
						}
					}
					
					// Add an invocation to another update method (for a chain of update method invocations).
					for (Edge resToCh2: resourceNode.getOutEdges()) {
						DataFlowEdge dOut = (DataFlowEdge) resToCh2;
						DataTransferChannel ch2 = ((ChannelNode) resToCh2.getDestination()).getChannel();
						// Check if the input resource is outside of the channel scope.
						boolean outsideInputResource2 = false;
						Set<ChannelMember> outsideInputMembers2 = new HashSet<>();
						for (ChannelMember cm: ch2.getInputChannelMembers()) {
							if (cm.isOutside()) {
								outsideInputMembers2.add(cm);
								if (cm.getResource().getResourceHierarchy().equals(resourceNode.getResourceHierarchy())) {
									outsideInputResource2 = true;	// Regarded as pull transfer.
								}
							}
						}
						if (((PushPullAttribute) dOut.getAttribute()).getOptions().get(0) == PushPullValue.PUSH && !outsideInputResource2) {
							for (Edge chToRes2: resToCh2.getDestination().getOutEdges()) {
								// PUSH transfer
								ChannelMember in = null;
								for (ChannelMember cm: ch2.getInputChannelMembers()) {
									if (cm.getResource().equals(resourceNode.getOutSideResource())) {
										in = cm;
										break;
									}
								}
								Map<MethodDeclaration, Set<ResourcePath>> referredResources = new HashMap<>(); 
								List<String> params = new ArrayList<>();
								params.add(langSpec.getFieldAccessor(fieldOfResourceState));
								Set<ResourcePath> referredSet = referredResources.get(update);
								for (ChannelMember rc: ch2.getReferenceChannelMembers()) {
									// to get the value of reference member.
									ResourcePath ref = rc.getResource();
									if (referredSet == null) {
										referredSet = new HashSet<>();
										referredResources.put(update, referredSet);
									}
									if (!resourceNode.getInSideResources().contains(ref)) {
										String refVarName = ref.getResourceName();
										if (!referredSet.contains(ref)) {
											referredSet.add(ref);
											Expression refGetter = getPullAccessor().getCurrentStateAccessorFor(rc, in);
											String[] sideEffects = new String[] {""};
											String refExp = refGetter.toImplementation(sideEffects);
											String refTypeName = ref.getResourceStateType().getInterfaceTypeName();
											update.addFirstStatement(sideEffects[0] + langSpec.getVariableDeclaration(refTypeName, refVarName) + langSpec.getAssignment() + refExp + langSpec.getStatementDelimiter());
										}
										params.add(refVarName);
									}
								}
								update.addStatement(langSpec.getMethodInvocation(langSpec.getFieldAccessor(((ResourceNode) chToRes2.getDestination()).getResourceName()), 
																					updateMethodName + resComponentName, 
																					params) + langSpec.getStatementDelimiter());	// this.dst.updateSrc(value, refParams);
							}
						}
						if (outsideInputMembers2.size() > 0) {
							if (!generatesComponent(resourceNode.getResourceHierarchy())) {
								// srcRes2 does not have a component.
								ResourcePath srcRes2 = resourceNode.getOutSideResource();
								for (ChannelMember out: ch2.getOutputChannelMembers()) {
									if (!generatesComponent(out.getResource().getResourceHierarchy())) {
										// Also dstRes2 does not have a component.
										ResourcePath dstRes2 = out.getResource();
										if (srcRes2.getParent().equals(dstRes2.getParent())) {
											Map<ChannelMember, Entry<ResourcePath, Set<ChannelMember>>> resourcePaths = null;
											try {
												resourcePaths = ch2.fillOutsideResourcePaths(out, getPullAccessor());
												if (resourcePaths != null && resourcePaths.size() > 0) {
													for (ChannelMember outsideMember: outsideInputMembers2) {
														for (ChannelMember dependingMember: resourcePaths.get(outsideMember).getValue()) {
															if (dependingMember.getResource().equals(srcRes2)) {
																// An outside input resource path depends on srcRes.
																ResourcePath outsidePath = resourcePaths.get(outsideMember).getKey();
																if (!generatesComponent(outsidePath.getResourceHierarchy())) {
																	outsidePath = outsidePath.getParent();
																}
																String outsideResName = langSpec.toVariableName(getComponentName(outsidePath.getResourceHierarchy(), langSpec));
																Expression outsideExp = getPullAccessor().getDirectStateAccessorFor(outsidePath, null);
																if (generatesComponent(outsidePath.getResourceHierarchy())) {
																	outsideExp = ((Term) outsideExp).getChild(0);
																}
																Expression nextExp = dependingMember.getStateTransition().getNextStateExpression();
																if (nextExp != null && outsideExp instanceof Term) {
																	if (nextExp instanceof Variable) {
																		outsideExp = ((Term) outsideExp).substitute((Variable) nextExp, new Field(langSpec.toVariableName(getComponentName(dependingMember.getResource().getResourceHierarchy(), langSpec)))); 
																	} else {
																		// ToDo.
																	}
																}
																String[] sideEffects = new String[] {""};
																String outsideAccessor = outsideExp.toImplementation(sideEffects);
																String updateReference = langSpec.getFieldAccessor(outsideResName) + langSpec.getAssignment() + outsideAccessor + langSpec.getStatementDelimiter();
																update.addStatement(updateReference);			// Update the reference field.
																// Update constructor.
																if (component != null) {
																	MethodDeclaration constructor = getConstructor(component);
																	constructor.addStatement(updateReference);		// Initialize the reference field.
																} else if (parentComponent != null) {
																	constructorStatements.add(updateReference);
																}
															}
														}
													}
												}
											} catch (ParameterizedIdentifierIsFutureWork | ResolvingMultipleDefinitionIsFutureWork
													| InvalidMessage | UnificationFailed | ValueUndefined e) {
												e.printStackTrace();
											}
										}
									}
								}
							}
						}
					}
				}
			}
		}
		return new AbstractMap.SimpleEntry<>(constructorStatements, updateStatements);
	}
	
	private Map.Entry<List<String>, Map<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>>> declareInputMethodsInThisAndMainComponents(ResourceNode resourceNode, TypeDeclaration component,
			TypeDeclaration parentComponent, TypeDeclaration mainComponent, DataTransferModel model, ILanguageSpecific langSpec) {
		// Declare input methods.
		String resName = resourceNode.getResourceName();
		String resComponentName = langSpec.toComponentName(resName);
		List<String> constructorStatements = new ArrayList<>();
		Map<MethodDeclaration, Map.Entry<Expression, ResourceHierarchy>> inputStatements = new HashMap<>();
		for (Channel ch : model.getIOChannels()) {
			for (ChannelMember out : ((DataTransferChannel) ch).getOutputChannelMembers()) {
				if (resourceNode.getInSideResources().contains(out.getResource())) {
					Expression message = out.getStateTransition().getMessageExpression();
					MethodDeclaration input = null;
					MethodDeclaration inputAccessor = null;
					if (message instanceof Term) {
						// Declare an input method in this component.
						ArrayList<VariableDeclaration> resInputParams = new ArrayList<>();
						ArrayList<VariableDeclaration> mainInputParams = new ArrayList<>();
						int v = 1;
						for (Selector selector: resourceNode.getSelectors()) {
							if (selector.getExpression() instanceof Variable) {
								Variable var = (Variable) selector.getExpression();
								resInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));								
								mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));								
							} else if (selector.getExpression() instanceof Term) {
								Term var = (Term) selector.getExpression();
								resInputParams.add(langSpec.newVariableDeclaration(var.getType(), "v" + v));								
								mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), "v" + v));								
							}
							v++;
						}
						if (resourceNode.getParent() != null) {
							for (Selector selector: resourceNode.getParent().getAllSelectors()) {
								if (selector.getExpression() instanceof Variable) {
									Variable var = (Variable) selector.getExpression();
									mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));								
								} else if (selector.getExpression() instanceof Term) {
									Term var = (Term) selector.getExpression();
									mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), "v" + v));								
								}
								v++;
							}
						}
						for (Variable var: message.getVariables().values()) {
							resInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));
							mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));
						}
						input = langSpec.newMethodDeclaration(((Term) message).getSymbol().getImplName(), false, null, resInputParams);
						if (component != null) {
							// A component is created for this resource.
							component.addMethod(input);
						} else if (parentComponent != null) {
							// No component is created for this resource.
							parentComponent.addMethod(input);
						}
						
						// Declare the accessor in the main component to call the input method.
						String str = ((Term) message).getSymbol().getImplName();
						inputAccessor = getMethod(mainComponent, str);
						if (inputAccessor == null) {
							inputAccessor = langSpec.newMethodDeclaration(str, false, null, mainInputParams);
							mainComponent.addMethod(inputAccessor);
						} else {
							// Add type to a parameter without type.
							if (inputAccessor.getParameters() != null) {
								for (VariableDeclaration param: inputAccessor.getParameters()) {
									if (param.getType() == null) {
										for (VariableDeclaration p: mainInputParams) {
											if (param.getName().equals(p.getName()) && p.getType() != null) {
												param.setType(p.getType());
											}
										}
									}
								}
							}
						}
					} else if (message instanceof Variable) {
						// Declare an input method in this component.
						ArrayList<VariableDeclaration> resInputParams = new ArrayList<>();
						ArrayList<VariableDeclaration> mainInputParams = new ArrayList<>();
						int v = 1;
						for (Selector selector: resourceNode.getSelectors()) {
							if (selector.getExpression() instanceof Variable) {
								Variable var = (Variable) selector.getExpression();
								resInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));								
								mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));								
							} else if (selector.getExpression() instanceof Term) {
								Term var = (Term) selector.getExpression();
								resInputParams.add(langSpec.newVariableDeclaration(var.getType(), "v" + v));								
								mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), "v" + v));								
							}
							v++;
						}
						if (resourceNode.getResourceHierarchy().getParent() != null) {
							for (Selector selector: resourceNode.getParent().getSelectors()) {
								if (selector.getExpression() instanceof Variable) {
									Variable var = (Variable) selector.getExpression();
									mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), var.getName()));								
								} else if (selector.getExpression() instanceof Term) {
									Term var = (Term) selector.getExpression();
									mainInputParams.add(langSpec.newVariableDeclaration(var.getType(), "v" + v));								
								}
								v++;
							}
						}
						if (resInputParams.size() == 0) {
							input = langSpec.newMethodDeclaration(((Variable) message).getName(), null);
						} else {
							input = langSpec.newMethodDeclaration(((Variable) message).getName(), false, null, resInputParams);							
						}
						if (component != null) {
							// A component is created for this resource.
							component.addMethod(input);
						} else if (parentComponent != null) {
							// No component is created for this resource.
							parentComponent.addMethod(input);
						}
												
						// Declare the accessor in the main component to call the input method.
						String str = ((Variable) message).getName();
						inputAccessor = getMethod(mainComponent, str);
						if (inputAccessor == null) {
							if (mainInputParams.size() == 0) {
								inputAccessor = langSpec.newMethodDeclaration(str, null);
							} else {
								inputAccessor = langSpec.newMethodDeclaration(str, false, null, mainInputParams);
							}
							mainComponent.addMethod(inputAccessor);
						}
					}
					
					// Add an invocation to the accessor method.
					if (inputAccessor != null) {
						Expression resExp = getPullAccessor().getDirectStateAccessorFor(out.getResource(), null);
						List<String> args = new ArrayList<>();
						if (resExp instanceof Term) {
							// to access the parent
							if (((Term) resExp).getChildren().size() > 1 && ((Term) resExp).getChild(1) instanceof Variable) {
								args.add(((Variable)((Term) resExp).getChild(1)).getName());
							}
							resExp = ((Term) resExp).getChild(0);
						}
						String resourceAccess = resExp.toImplementation(new String[] {null});
						if (message instanceof Term) {
							for (Variable var: message.getVariables().values()) {
								args.add(var.getName());
							}
						}
						inputAccessor.addStatement(langSpec.getMethodInvocation(resourceAccess, input.getName(), args) + langSpec.getStatementDelimiter());
					}
					
					if (input != null) {
						// Add a statement to update the state field to the input method.
						try {
							Expression updateExp = ((DataTransferChannel) ch).deriveUpdateExpressionOf(out, getPullAccessor());
							// Replace Json constructor with a constructor of the child resource.
							ResourceHierarchy outRes = out.getResource().getResourceHierarchy();
							if (outRes.getChildren().size() == 1 && outRes.getChildren().iterator().next().getNumParameters() > 0) {
								ResourceHierarchy childRes = outRes.getChildren().iterator().next();
								Type childStateType = childRes.getResourceStateType();
								if (DataConstraintModel.typeJson.isAncestorOf(childStateType)) {
									inputStatements.put(input, new AbstractMap.SimpleEntry<>(updateExp, childRes));
									updateExp = null;
								}
							}
							// Add statements to the input method.
							if (updateExp != null) {
								String[] sideEffects = new String[] {""};
								String newState = updateExp.toImplementation(sideEffects);
								ResourceHierarchy resource = resourceNode.getResourceHierarchy();
								if (generatesComponent(resource)) {
									String updateStatement;
									if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
										updateStatement = sideEffects[0];	
									} else {
										updateStatement = sideEffects[0] + langSpec.getFieldAccessor(fieldOfResourceState) + langSpec.getAssignment() + newState + langSpec.getStatementDelimiter();
									}
									input.addFirstStatement(updateStatement);
								} else {
									String updateStatement = null;
									if (updateExp instanceof Term && ((Term) updateExp).getSymbol().isImplWithSideEffect()) {
										// ToDo.
										updateStatement = sideEffects[0];	
									} else {
										if (DataConstraintModel.typeList.isAncestorOf(resourceNode.getParent().getResourceStateType())) {
											Term selector = new Term(DataConstraintModel.set);
											selector.addChild(new Constant(langSpec.getFieldAccessor(fieldOfResourceState)));
											selector.addChild(new Variable(input.getParameters().get(input.getParameters().size() - 2).getName()));
											selector.addChild(new Constant(newState));
											String[] sideEffects2 = new String[] {""};
											String newList = selector.toImplementation(sideEffects2);
											updateStatement = sideEffects[0] + sideEffects2[0];
										} else if (DataConstraintModel.typeMap.isAncestorOf(resourceNode.getParent().getResourceStateType())) {
											Term selector = new Term(DataConstraintModel.insert);
											selector.addChild(new Constant(langSpec.getFieldAccessor(fieldOfResourceState)));
											selector.addChild(new Variable(input.getParameters().get(input.getParameters().size() - 2).getName()));
											selector.addChild(new Constant(newState));
											String[] sideEffects2 = new String[] {""};
											String newMap = selector.toImplementation(sideEffects2);
											updateStatement = sideEffects[0] + sideEffects2[0];
										} else {
											String resourceName = langSpec.toVariableName(getComponentName(resource, langSpec));
											updateStatement = sideEffects[0] + langSpec.getFieldAccessor(resourceName) + langSpec.getAssignment() + newState + langSpec.getStatementDelimiter();
										}
										if (updateStatement != null) {
											input.addFirstStatement(updateStatement);
										}
									}
								}
							}
						} catch (ParameterizedIdentifierIsFutureWork | ResolvingMultipleDefinitionIsFutureWork
								| InvalidMessage | UnificationFailed | ValueUndefined e) {
							e.printStackTrace();
						}
												
						// Add an invocation to an update method (for a chain of update method invocations).
						for (Edge resToCh: resourceNode.getOutEdges()) {
							DataFlowEdge dOut = (DataFlowEdge) resToCh;
							DataTransferChannel ch2 = ((ChannelNode) resToCh.getDestination()).getChannel();
							boolean outsideInputResource2 = false;
							Set<ChannelMember> outsideInputMembers2 = new HashSet<>();
							for (ChannelMember cm: ch2.getInputChannelMembers()) {
								if (cm.isOutside()) {
									outsideInputMembers2.add(cm);
									if (cm.getResource().getResourceHierarchy().equals(resourceNode.getResourceHierarchy())) {
										outsideInputResource2 = true;	// Regarded as pull transfer.
									}
								}
							}
							if (((PushPullAttribute) dOut.getAttribute()).getOptions().get(0) == PushPullValue.PUSH && !outsideInputResource2) {
								for (Edge chToRes: resToCh.getDestination().getOutEdges()) {
									// PUSH transfer
									ChannelMember in = null;
									for (ChannelMember cm: ch2.getInputChannelMembers()) {
										if (cm.getResource().equals(resourceNode.getOutSideResource())) {
											in = cm;
											break;
										}
									}
									Map<MethodDeclaration, Set<ResourcePath>> referredResources = new HashMap<>(); 
									List<String> params = new ArrayList<>();
									params.add(langSpec.getFieldAccessor(fieldOfResourceState));
									Set<ResourcePath> referredSet = referredResources.get(input);
									for (ChannelMember rc: ch2.getReferenceChannelMembers()) {
										// to get the value of reference member.
										ResourcePath ref = rc.getResource();
										if (referredSet == null) {
											referredSet = new HashSet<>();
											referredResources.put(input, referredSet);
										}
										if (!ref.equals(resourceNode.getOutSideResource())) {
											String refVarName = ref.getResourceName();
											if (!referredSet.contains(ref)) {
												referredSet.add(ref);
												Expression refGetter = getPullAccessor().getCurrentStateAccessorFor(rc, in);
												String[] sideEffects = new String[] {""};
												String refExp = refGetter.toImplementation(sideEffects);
												String refTypeName = ref.getResourceStateType().getInterfaceTypeName();
												input.addFirstStatement(sideEffects[0] + langSpec.getVariableDeclaration(refTypeName, refVarName) + langSpec.getAssignment() + refExp + langSpec.getStatementDelimiter());
											}
											params.add(refVarName);
										}
									}
									input.addStatement(langSpec.getMethodInvocation(langSpec.getFieldAccessor(((ResourceNode) chToRes.getDestination()).getResourceName()), 
																						updateMethodName + resComponentName, 
																						params) + langSpec.getStatementDelimiter());	// this.dst.updateSrc(value, refParams);
								}
							}
							if (outsideInputMembers2.size() > 0) {
								if (!generatesComponent(resourceNode.getResourceHierarchy())) {
									ResourcePath srcRes2 = resourceNode.getOutSideResource();
									for (ChannelMember out2: ch2.getOutputChannelMembers()) {
										if (!generatesComponent(out2.getResource().getResourceHierarchy())) {
											ResourcePath dstRes2 = out2.getResource();
											if (srcRes2.getParent().equals(dstRes2.getParent())) {
												Map<ChannelMember, Entry<ResourcePath, Set<ChannelMember>>> resourcePaths = null;
												try {
													resourcePaths = ch2.fillOutsideResourcePaths(out2, getPullAccessor());
													if (resourcePaths != null && resourcePaths.size() > 0) {
														for (ChannelMember outsideMember: outsideInputMembers2) {
															for (ChannelMember dependingMember: resourcePaths.get(outsideMember).getValue()) {
																if (dependingMember.getResource().equals(srcRes2)) {
																	// An outside input resource path depends on srcRes.
																	ResourcePath outsidePath = resourcePaths.get(outsideMember).getKey();
																	if (!generatesComponent(outsidePath.getResourceHierarchy())) {
																		outsidePath = outsidePath.getParent();
																	}
																	String outsideResName = langSpec.toVariableName(getComponentName(outsidePath.getResourceHierarchy(), langSpec));
																	Expression outsideExp = getPullAccessor().getDirectStateAccessorFor(outsidePath, null);
																	if (generatesComponent(outsidePath.getResourceHierarchy())) {
																		outsideExp = ((Term) outsideExp).getChild(0);
																	}
																	Expression nextExp = dependingMember.getStateTransition().getNextStateExpression();
																	if (nextExp != null && outsideExp instanceof Term) {
																		if (nextExp instanceof Variable) {
																			outsideExp = ((Term) outsideExp).substitute((Variable) nextExp, new Field(langSpec.toVariableName(getComponentName(dependingMember.getResource().getResourceHierarchy(), langSpec)))); 
																		} else {
																			// ToDo.
																		}
																	}
																	String[] sideEffects = new String[] {""};
																	String outsideAccessor = outsideExp.toImplementation(sideEffects);
																	input.addStatement(langSpec.getFieldAccessor(outsideResName) + langSpec.getAssignment() + outsideAccessor + langSpec.getStatementDelimiter());		// change the reference field.
																	// Update constructor.
																	String initializingStatement = langSpec.getFieldAccessor(outsideResName) + langSpec.getAssignment() + outsideAccessor + langSpec.getStatementDelimiter();
																	if (component != null) {
																		MethodDeclaration constructor = getConstructor(component);
																		constructor.addStatement(initializingStatement);		// initialize the reference field.
																	} else {
																		constructorStatements.add(initializingStatement);		// initialize the reference field.
																	}
																}
															}
														}
													}
												} catch (ParameterizedIdentifierIsFutureWork | ResolvingMultipleDefinitionIsFutureWork
														| InvalidMessage | UnificationFailed | ValueUndefined e) {
													e.printStackTrace();
												}
											}
										}
									}
								}
							}
						}
					}
				}
			}
		}
		return new AbstractMap.SimpleEntry<>(constructorStatements, inputStatements);
	}
}