/*
* Copyright (c) 2006, 2010 Borland Software Corporation and others
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* bblajer - initial API and implementation
*/
package org.eclipse.gmf.tests.lite.gef;
import java.util.Collections;
import java.util.Iterator;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.draw2d.geometry.Rectangle;
import org.eclipse.emf.common.command.AbstractCommand;
import org.eclipse.emf.common.command.Command;
import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.edit.command.AddCommand;
import org.eclipse.emf.edit.command.RemoveCommand;
import org.eclipse.emf.edit.command.SetCommand;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.emf.transaction.util.TransactionUtil;
import org.eclipse.emf.workspace.EMFCommandOperation;
import org.eclipse.gef.EditPart;
import org.eclipse.gmf.runtime.notation.Bounds;
import org.eclipse.gmf.runtime.notation.CanonicalStyle;
import org.eclipse.gmf.runtime.notation.Diagram;
import org.eclipse.gmf.runtime.notation.Edge;
import org.eclipse.gmf.runtime.notation.Node;
import org.eclipse.gmf.runtime.notation.NotationFactory;
import org.eclipse.gmf.runtime.notation.NotationPackage;
import org.eclipse.gmf.runtime.notation.View;
import org.eclipse.gmf.tests.lite.gen.LiteGeneratorConfiguration;
import org.eclipse.gmf.tests.rt.GeneratedCanvasTest;
public class NotationRefreshTest extends GeneratedCanvasTest {
public NotationRefreshTest(String name) {
super(name, new LiteGeneratorConfiguration());
}
public void testNotationRefreshOnDeleteNode() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
View nodeA = getCanvasInstance().getNodeA();
EObject elementA = nodeA.getElement();
EditPart editPartA = findEditPart(nodeA);
Command command = RemoveCommand.create(editingDomain, elementA.eContainer(), elementA.eContainingFeature(), elementA);
assertTrue("Failed to obtain command to remove an instance of the domain model element", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertNull("RemoveCommand not executed properly", elementA.eContainer());
assertNull("Notational refresh failed on domain element removal", findView(diagram, elementA));
assertNull("EditPart not removed automatically", findEditPart(nodeA));
assertFalse(editPartA.isActive());
}
public void testNotationRefreshOnCreateNode() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
EStructuralFeature feature = getCanvasInstance().getNodeA().getElement().eContainmentFeature();
EClass newChildClass = getCanvasInstance().getNodeA().getElement().eClass();
EObject newChild = newChildClass.getEPackage().getEFactoryInstance().create(newChildClass);
Command command = AddCommand.create(editingDomain, diagramElement, feature, newChild);
assertTrue("Failed to obtain command to create a new instance of the domain model element", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertSame("AddCommand not executed properly", diagramElement, newChild.eContainer());
View newChildView = findView(diagram, newChild);
assertNotNull("Notational refresh failed on domain element creation", newChildView);
int visualId = getType(newChildView);
assertEquals(getSetup().getGenModel().getNodeA().getVisualID(), visualId);
EditPart newChildEP = findEditPart(newChildView);
assertNotNull("EditPart not created automatically", newChildEP);
}
public void testNotationRefreshOnCreateDirectChildNode() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
Node nodeB = getCanvasInstance().getNodeB();
EObject elementB = nodeB.getElement();
EStructuralFeature directNodeFeature = elementB.eClass().getEStructuralFeature("chapters");
assertNotNull("Child feature not found", directNodeFeature);
EClass chapterClass = (EClass) directNodeFeature.getEType();
EObject chapter = chapterClass.getEPackage().getEFactoryInstance().create(chapterClass);
Command command = AddCommand.create(editingDomain, elementB, directNodeFeature, chapter);
assertTrue("Failed to obtain command to create a new instance of the domain model element", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertSame("AddCommand not executed properly", elementB, chapter.eContainer());
View newChildView = findView(nodeB, chapter);
assertNotNull("Notational refresh failed on domain element creation", newChildView);
EditPart newChildEP = findEditPart(newChildView);
assertNotNull("EditPart not created automatically", newChildEP);
}
public void testNotationRefreshOnAttributeChangeThatAffectsSelector() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
Node nodeB = getCanvasInstance().getNodeB();
EObject elementB = nodeB.getElement();
Bounds bounds = (Bounds) nodeB.getLayoutConstraint();
// if (bounds == null) {
// bounds = NotationFactory.eINSTANCE.createBounds();
// }
Rectangle rectangle = new Rectangle(bounds.getX(), bounds.getY(), bounds.getWidth(), bounds.getHeight());
assertEquals("Unexpected visual ID of the element", getSetup().getGenModel().getNodeB().getVisualID(), getType(nodeB));
EditPart editPartB = findEditPart(nodeB);
Edge edge1 = getCanvasInstance().getLinkByClass();
EObject edge1DomainElement = edge1.getElement();
Edge edge2 = getCanvasInstance().getLinkByRef();
checkLinkEnd(edge1, nodeB);
checkLinkEnd(edge2, nodeB);
EditPart edge1EP = findEditPart(edge1);
EditPart edge2EP = findEditPart(edge2);
assertTrue(edge1EP.isActive());
assertTrue(edge2EP.isActive());
EClass elementBClass = elementB.eClass();
EStructuralFeature feature = elementBClass.getEStructuralFeature("pages"); //$NON-NLS-1$
assertNotNull("Failed to find the feature that affects selector", feature);
Integer newValue = new Integer(400);
Command command = SetCommand.create(editingDomain, elementB, feature, newValue);
assertTrue("Failed to obtain command to make a change that affects selector", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertEquals("SetCommand not executed properly", newValue, elementB.eGet(feature));
Node newNodeB = (Node) findView(diagram, elementB);
assertNotNull("Notational refresh failed to recreate a new node upon a change that affects selector", newNodeB);
assertNotSame("Notational refresh failed to replace a new node upon a change that affects selector", nodeB, newNodeB);
assertTrue("Notational refresh failed to change visual ID of the element upon a change that affects selector", getSetup().getGenModel().getNodeB().getVisualID() != getType(newNodeB));
EditPart newEditPartB = findEditPart(newNodeB);
assertNotNull("EditPart not recreated automatically", newEditPartB);
assertNotSame("EditPart not replaced automatically", editPartB, newEditPartB);
assertFalse(editPartB.isActive());
assertTrue(newEditPartB.isActive());
Bounds newBounds = (Bounds) newNodeB.getLayoutConstraint();
// if (newBounds == null) {
// newBounds = NotationFactory.eINSTANCE.createBounds();
// }
Rectangle newRectangle = new Rectangle(newBounds.getX(), newBounds.getY(), newBounds.getWidth(), newBounds.getHeight());
assertEquals("Notational refresh failed to position the new node where the old one was", rectangle, newRectangle);
assertFalse(edge2EP.isActive());
Node nodeA = getCanvasInstance().getNodeA();
Edge newEdge2 = findEdgeWithoutElement(diagram, newNodeB, nodeA, 0);
assertNotNull("Failed to find the new representation of edge-without-class", newEdge2);
EditPart newEdge2EP = findEditPart(newEdge2);
assertNotNull("Link EditPart not recreated automatically", newEdge2EP);
assertNotSame("Link EditPart not replaced automatically", newEdge2EP, edge2EP);
assertTrue(newEdge2EP.isActive());
checkLinkEnd(newEdge2, newNodeB);
assertFalse(edge1EP.isActive()); //Should have been replaced
//checkLinkEnd(edge1, newNodeB);
Edge newEdge1 = findEdgeWithElement(diagram, edge1DomainElement);
assertNotNull("Failed to find the new representation of edge-with-class", newEdge1);
EditPart newEdge1EP = findEditPart(newEdge1);
assertNotNull("Link EditPart not recreated automatically", newEdge1EP);
assertNotSame("Link EditPart not replaced automatically", newEdge1EP, edge1EP);
assertTrue(newEdge1EP.isActive());
checkLinkEnd(newEdge1, newNodeB);
}
public void testNotationRefreshOnSemanticRerouteWithClass() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
Node nodeB = getCanvasInstance().getNodeB(); //book
Node nodeA = getCanvasInstance().getNodeA(); //writer
EditPart bookEP = findEditPart(nodeB);
EditPart writerEP = findEditPart(nodeA);
assertNotNull(bookEP);
assertNotNull(writerEP);
Edge opinionsEdge = getCanvasInstance().getLinkByClass();
EObject opinion = opinionsEdge.getElement();
EditPart opinionEP = findEditPart(opinionsEdge);
checkLinkEnd(opinionsEdge, nodeA);
checkLinkEnd(opinionsEdge, nodeB);
//0. Create one element of each type
EClass writerClass = nodeA.getElement().eClass();
EObject newWriter = writerClass.getEPackage().getEFactoryInstance().create(writerClass);
Command writerCommand = AddCommand.create(editingDomain, diagramElement, nodeA.getElement().eContainmentFeature(), newWriter);
EClass bookClass = nodeB.getElement().eClass();
EObject newBook = bookClass.getEPackage().getEFactoryInstance().create(bookClass);
Command bookCommand = AddCommand.create(editingDomain, diagramElement, nodeB.getElement().eContainmentFeature(), newBook);
new EMFCommandOperation(editingDomain, writerCommand).execute(new NullProgressMonitor(), null);
new EMFCommandOperation(editingDomain, bookCommand).execute(new NullProgressMonitor(), null);
Node nodeA1 = (Node) findView(diagram, newWriter);
Node nodeB1 = (Node) findView(diagram, newBook);
//1. Check reroute target of a link-by-class.
EStructuralFeature targetByClassFeature = opinion.eClass().getEStructuralFeature("book");
Command command = SetCommand.create(editingDomain, opinion, targetByClassFeature, newBook);
assertTrue("Failed to create semantic reroute command", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertSame("Command not executed", newBook, opinion.eGet(targetByClassFeature));
assertTrue(opinionEP.isActive());
checkLinkEnd(opinionsEdge, nodeA);
checkLinkEnd(opinionsEdge, nodeB1);
//2. Check reroute source of a link-by-class.
EStructuralFeature sourceByClassFeature = opinion.eClass().getEStructuralFeature("writer");
command = SetCommand.create(editingDomain, opinion, sourceByClassFeature, newWriter);
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertSame("Command not executed", newWriter, opinion.eGet(sourceByClassFeature));
assertTrue(opinionEP.isActive());
checkLinkEnd(opinionsEdge, nodeA1);
checkLinkEnd(opinionsEdge, nodeB1);
}
public void testNotationRefreshOnSemanticRerouteWithFeature() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
Node nodeB = getCanvasInstance().getNodeB(); //book
Node nodeA = getCanvasInstance().getNodeA(); //writer
EditPart bookEP = findEditPart(nodeB);
EditPart writerEP = findEditPart(nodeA);
assertNotNull(bookEP);
assertNotNull(writerEP);
Edge author = getCanvasInstance().getLinkByRef();
checkLinkEnd(author, nodeA);
checkLinkEnd(author, nodeB);
EditPart authorEP = findEditPart(author);
//0. Create one element of each type
EClass writerClass = nodeA.getElement().eClass();
final EObject newWriter = writerClass.getEPackage().getEFactoryInstance().create(writerClass);
Command writerCommand = AddCommand.create(editingDomain, diagramElement, nodeA.getElement().eContainmentFeature(), newWriter);
EClass bookClass = nodeB.getElement().eClass();
final EObject newBook = bookClass.getEPackage().getEFactoryInstance().create(bookClass);
Command bookCommand = AddCommand.create(editingDomain, diagramElement, nodeB.getElement().eContainmentFeature(), newBook);
new EMFCommandOperation(editingDomain, writerCommand).execute(new NullProgressMonitor(), null);
new EMFCommandOperation(editingDomain, bookCommand).execute(new NullProgressMonitor(), null);
Node nodeA1 = (Node) findView(diagram, newWriter);
Node nodeB1 = (Node) findView(diagram, newBook);
//1. Check reroute target of a link-by-class.
EStructuralFeature targetFeature = nodeB.getElement().eClass().getEStructuralFeature("author");
Command command = SetCommand.create(editingDomain, nodeB.getElement(), targetFeature, newWriter);
assertTrue("Failed to create semantic reroute command", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertSame("Command not executed", newWriter, nodeB.getElement().eGet(targetFeature));
assertTrue(authorEP.isActive());
checkLinkEnd(author, nodeA1);
checkLinkEnd(author, nodeB);
//2. Check reroute source of a link-by-class.
EStructuralFeature sourceFeature = nodeA.getElement().eClass().getEStructuralFeature("books");
final Command rerouteSourceCommand = SetCommand.create(editingDomain, newWriter, sourceFeature, Collections.singletonList(newBook));
//workaround: command.canExecute() fails with an exception, because it actually attempts to modify elements without a write transaction.
new EMFCommandOperation(editingDomain, new AbstractCommand() {
public boolean canExecute() {
return true;
}
public void redo() {
}
public void execute() {
assertTrue(rerouteSourceCommand != null && rerouteSourceCommand.canExecute());
}
}).execute(new NullProgressMonitor(), null);
new EMFCommandOperation(editingDomain, rerouteSourceCommand).execute(new NullProgressMonitor(), null);
assertNull("Command not executed", nodeB.getElement().eGet(targetFeature));
assertSame("Command not executed", newWriter, nodeB1.getElement().eGet(targetFeature));
assertFalse(authorEP.isActive());
Edge newAuthor = findEdgeWithoutElement(diagram, nodeB1, nodeA1, 0);
assertNotNull(newAuthor);
EditPart newAuthorEP = findEditPart(newAuthor);
assertNotNull(newAuthorEP);
assertTrue(newAuthorEP.isActive());
}
public void testNotationRefreshOnDeleteLink() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
Node nodeB = getCanvasInstance().getNodeB(); //book
Node nodeA = getCanvasInstance().getNodeA(); //writer
EditPart bookEP = findEditPart(nodeB);
EditPart writerEP = findEditPart(nodeA);
assertNotNull(bookEP);
assertNotNull(writerEP);
Edge author = getCanvasInstance().getLinkByRef();
checkLinkEnd(author, nodeA);
checkLinkEnd(author, nodeB);
EditPart authorEP = findEditPart(author);
assertNotNull(authorEP);
assertTrue(authorEP.isActive());
EStructuralFeature targetFeature = nodeB.getElement().eClass().getEStructuralFeature("author");
assertSame(nodeA.getElement(), nodeB.getElement().eGet(targetFeature));
final Command command = SetCommand.create(editingDomain, nodeB.getElement(), targetFeature, SetCommand.UNSET_VALUE);
//workaround: command.canExecute() fails with an exception, because it actually attempts to modify elements without a write transaction.
new EMFCommandOperation(editingDomain, new AbstractCommand() {
public boolean canExecute() {
return true;
}
public void redo() {
}
public void execute() {
assertTrue("Failed to create remove semantic link command", command != null && command.canExecute());
}
}).execute(new NullProgressMonitor(), null);
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertNull("Command not executed", nodeB.getElement().eGet(targetFeature));
assertNull(author.eContainer());
assertFalse(authorEP.isActive());
}
public void testNotationRefreshOnSemanticRerouteLinkToNowhere() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
Node nodeB = getCanvasInstance().getNodeB(); //book
Node nodeA = getCanvasInstance().getNodeA(); //writer
EditPart bookEP = findEditPart(nodeB);
EditPart writerEP = findEditPart(nodeA);
assertNotNull(bookEP);
assertNotNull(writerEP);
Edge opinionsEdge = getCanvasInstance().getLinkByClass();
EObject opinion = opinionsEdge.getElement();
EditPart opinionEP = findEditPart(opinionsEdge);
checkLinkEnd(opinionsEdge, nodeA);
checkLinkEnd(opinionsEdge, nodeB);
EStructuralFeature targetByClassFeature = opinion.eClass().getEStructuralFeature("book");
final Command command = SetCommand.create(editingDomain, opinion, targetByClassFeature, SetCommand.UNSET_VALUE);
//the returned command is a strict pessimistic command, so canExecute() can only be called from within a transaction.
new EMFCommandOperation(editingDomain, new AbstractCommand() {
public void redo() {
}
public void execute() {
assertTrue("Failed to create semantic reroute command", command != null && command.canExecute());
}
}).execute(new NullProgressMonitor(), null);
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertNull("Command not executed", opinion.eGet(targetByClassFeature));
assertFalse(opinionEP.isActive());
assertNull(opinionsEdge.eContainer());
}
public void testNotationRefreshOnCreateLink() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
Node nodeB = getCanvasInstance().getNodeB(); //book
Node nodeA = getCanvasInstance().getNodeA(); //writer
EditPart bookEP = findEditPart(nodeB);
EditPart writerEP = findEditPart(nodeA);
assertNotNull(bookEP);
assertNotNull(writerEP);
EClass bookClass = nodeB.getElement().eClass();
final EObject newBook = bookClass.getEPackage().getEFactoryInstance().create(bookClass);
Command bookCommand = AddCommand.create(editingDomain, diagramElement, nodeB.getElement().eContainmentFeature(), newBook);
new EMFCommandOperation(editingDomain, bookCommand).execute(new NullProgressMonitor(), null);
Node nodeB1 = (Node) findView(diagram, newBook);
EStructuralFeature targetFeature = nodeB.getElement().eClass().getEStructuralFeature("author");
Command command = SetCommand.create(editingDomain, newBook, targetFeature, nodeA.getElement());
assertTrue("Failed to create create semantic link command", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertSame("Command not executed", nodeA.getElement(), newBook.eGet(targetFeature));
Edge newAuthor = findEdgeWithoutElement(diagram, nodeB1, nodeA, 0);
assertNotNull("Failed to create edge in response to semantic link creation", newAuthor);
checkLinkEnd(newAuthor, nodeA);
checkLinkEnd(newAuthor, nodeB1);
EditPart newAuthorEP = findEditPart(newAuthor);
assertNotNull(newAuthorEP);
assertTrue(newAuthorEP.isActive());
}
public void testCanonicalStyle() throws Exception {
EditPart diagramEP = getDiagramEditPart();
Diagram diagram = (Diagram) diagramEP.getModel();
EObject diagramElement = diagram.getElement();
TransactionalEditingDomain editingDomain = TransactionUtil.getEditingDomain(diagramElement);
EStructuralFeature feature = getCanvasInstance().getNodeA().getElement().eContainmentFeature();
EClass newChildClass = getCanvasInstance().getNodeA().getElement().eClass();
EObject newChild = newChildClass.getEPackage().getEFactoryInstance().create(newChildClass);
CanonicalStyle style = NotationFactory.eINSTANCE.createCanonicalStyle();
style.setCanonical(false);
Command uncanonicalizeCommand = AddCommand.create(editingDomain, diagram, NotationPackage.eINSTANCE.getView_Styles(), style);
new EMFCommandOperation(editingDomain, uncanonicalizeCommand).execute(new NullProgressMonitor(), null);
Command command = AddCommand.create(editingDomain, diagramElement, feature, newChild);
assertTrue("Failed to obtain command to create a new instance of the domain model element", command != null && command.canExecute());
new EMFCommandOperation(editingDomain, command).execute(new NullProgressMonitor(), null);
assertSame("AddCommand not executed properly", diagramElement, newChild.eContainer());
View newChildView = findView(diagram, newChild);
assertNull("Notational child created for a view whose isCanonical() is false", newChildView);
Command canonicalizeCommand = SetCommand.create(editingDomain, style, NotationPackage.eINSTANCE.getCanonicalStyle_Canonical(), Boolean.TRUE);
new EMFCommandOperation(editingDomain, canonicalizeCommand).execute(new NullProgressMonitor(), null);
newChildView = findView(diagram, newChild);
assertNotNull("Setting view's isCanonical() to true should create missing notational children", newChildView);
int visualId = getType(newChildView);
assertEquals(getSetup().getGenModel().getNodeA().getVisualID(), visualId);
EditPart newChildEP = findEditPart(newChildView);
assertNotNull("EditPart not created automatically", newChildEP);
}
private void checkLinkEnd(Edge edge, Node node) {
assertTrue(node.equals(edge.getSource()) || node.equals(edge.getTarget()));
}
private int getType(View view) {
return Integer.parseInt(view.getType());
}
private View findView(View container, EObject child) {
for(Iterator<?> it = container.getChildren().iterator(); it.hasNext(); ) {
View next = (View) it.next();
if (child.equals(next.getElement())) {
return next;
}
}
return null;
}
private Edge findEdgeWithElement(Diagram diagram, EObject element) {
for(Iterator<?> it = diagram.getEdges().iterator(); it.hasNext(); ) {
Edge next = (Edge) it.next();
if (next.isSetElement() && next.getElement() == element) {
return next;
}
}
return null;
}
private Edge findEdgeWithoutElement(Diagram diagram, View source, View target, int index) {
int count = 0;
for(Iterator<?> it = diagram.getEdges().iterator(); it.hasNext(); ) {
Edge next = (Edge) it.next();
if (next.isSetElement() && next.getElement() == null) {
if (next.getSource() == source && next.getTarget() == target) {
if (count == index) {
return next;
}
count++;
}
}
}
return null;
}
}
