Bug 527333 - [Sequence Diagram] Some error exist in event replacement

for execution specification

 - ExecSpec event replacement:
    - can't link message to the start or the finish of an execution
specification if a messageEnd is already set.

 - UpdateExecSpecWeakRef:
    - do not move message if it is at start event
    - just move first found element, other will follow the move
    
 - Cast error fix when target or source is related to an other message.
 
 -...

Change-Id: I5c4034b5259d20d6544eb0df10bf1628930450ed
Signed-off-by: Mickael ADAM <mickael.adam@all4tec.net>

4 files changed, 195 insertions, 175 deletions

diff --git a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/edit/policies/UpdateWeakReferenceForExecSpecEditPolicy.java b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/edit/policies/UpdateWeakReferenceForExecSpecEditPolicy.java
index 92e943877e2..be73d8d3482 100644
--- a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/edit/policies/UpdateWeakReferenceForExecSpecEditPolicy.java
+++ b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/edit/policies/UpdateWeakReferenceForExecSpecEditPolicy.java
@@ -42,6 +42,7 @@ import org.eclipse.papyrus.uml.diagram.sequence.edit.parts.AbstractExecutionSpec
 import org.eclipse.papyrus.uml.diagram.sequence.edit.parts.AbstractMessageEditPart;
 import org.eclipse.papyrus.uml.diagram.sequence.edit.parts.LifelineEditPart;
 import org.eclipse.papyrus.uml.diagram.sequence.part.UMLDiagramEditorPlugin;
+import org.eclipse.papyrus.uml.diagram.sequence.referencialgrilling.GridManagementEditPolicy;
 import org.eclipse.papyrus.uml.diagram.sequence.util.LifelineEditPartUtil;
 import org.eclipse.papyrus.uml.diagram.sequence.util.LogOptions;
 import org.eclipse.papyrus.uml.diagram.sequence.util.SequenceUtil;
@@ -57,13 +58,15 @@ import org.eclipse.uml2.uml.OccurrenceSpecification;
  *
  */
 public class UpdateWeakReferenceForExecSpecEditPolicy extends UpdateWeakReferenceEditPolicy {
-
 	public static final String UDPATE_WEAK_REFERENCE_FOR_EXECSPEC = "UpdateWeakReferenceForExecSpecEditPolicy"; //$NON-NLS-1$
 
 	/**
 	 * @see org.eclipse.gef.editpolicies.AbstractEditPolicy#getCommand(org.eclipse.gef.Request)
+	 *
 	 * @param request
 	 * @return
+	 * 
+	 * 
 	 * 		<img src="../../../../../../../../../icons/sequenceScheme.png" width="250" />
 	 *         <UL>
 	 *         <LI>when move E --> move B on the coordinate Y of E and move A on the coordinate Y of E
@@ -107,8 +110,8 @@ public class UpdateWeakReferenceForExecSpecEditPolicy extends UpdateWeakReferenc
 	 */
 	private Command getUpdateWeakRefForExecSpecCreate(final CreateViewAndElementRequest request) {
 		Command command = null;
-		CreateViewAndElementRequest createRequest = request;
-		UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "Execution Specification creation request at:" + ((IAdaptable) getHost()).getAdapter(View.class).getElement());
+		CreateViewAndElementRequest createRequest = (CreateViewAndElementRequest) request;
+		UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "Execution Specification creation request at:" + ((View) ((IAdaptable) getHost()).getAdapter(View.class)).getElement());
 		// Snap to grid Location
 		createRequest.setLocation(SequenceUtil.getSnappedLocation(getHost(), createRequest.getLocation()));
 
@@ -117,80 +120,79 @@ public class UpdateWeakReferenceForExecSpecEditPolicy extends UpdateWeakReferenc
 		getHostFigure().translateToRelative(reqlocationOnScreen);
 
 		UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "=> Request Location on screen: " + reqlocationOnScreen);
-		List<OccurrenceSpecification> nextEventsFromPosition = new ArrayList<>();
-		List<OccurrenceSpecification> previousEventsFromPosition = new ArrayList<>();
+		List<OccurrenceSpecification> nextEventsFromPosition = new ArrayList<OccurrenceSpecification>();
+		List<OccurrenceSpecification> previousEventsFromPosition = new ArrayList<OccurrenceSpecification>();
 
 		// Get next and previous event from the lifeline source
 		EditPart host = getHost();
 		if (host instanceof LifelineEditPart) {
-			nextEventsFromPosition.addAll(LifelineEditPartUtil.getNextEventsFromPosition(reqlocationOnScreen, (LifelineEditPart) host));
+			nextEventsFromPosition.addAll(LifelineEditPartUtil.getNextEventsFromPosition(reqlocationOnScreen.getCopy().translate(0, GridManagementEditPolicy.threshold), (LifelineEditPart) host));
 			previousEventsFromPosition.addAll(LifelineEditPartUtil.getPreviousEventsFromPosition(new Point(reqlocationOnScreen.x, reqlocationOnScreen.y + deltaMoveAtCreationAndDeletion + AbstractExecutionSpecificationEditPart.DEFAUT_HEIGHT),
 					(LifelineEditPart) host));
 		}
 
+		// get the list of element just below new created message
+		nextEventsFromPosition.retainAll(previousEventsFromPosition);
+
 		if (!nextEventsFromPosition.isEmpty()) {
 			CompoundCommand compoundCommand = new CompoundCommand();
-			// get the list of element just below new created message
-			nextEventsFromPosition.retainAll(previousEventsFromPosition);
-
-			// For each next event below
-			for (OccurrenceSpecification nextEvent : nextEventsFromPosition) {
-				UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\tNext Event: " + nextEvent);
-
-				ArrayList<EditPart> senderList = SenderRequestUtils.getSenders(request);
-
-				List<?> connectionsAndChildren = new ArrayList<>();
-				connectionsAndChildren.addAll(((GraphicalEditPart) host).getSourceConnections());
-				connectionsAndChildren.addAll(((GraphicalEditPart) host).getTargetConnections());
-				connectionsAndChildren.addAll(((GraphicalEditPart) host).getChildren());
-
-				for (Object editPart : connectionsAndChildren) {
-					// move messages
-					if (editPart instanceof ConnectionEditPart) {
-						EObject message = ((View) ((AbstractMessageEditPart) editPart).getAdapter(View.class)).getElement();
-						if (message instanceof Message && null != ((Message) message).getSendEvent() && ((Message) message).getSendEvent().equals(nextEvent)
-								|| message instanceof Message && null != ((Message) message).getReceiveEvent() && ((Message) message).getReceiveEvent().equals(nextEvent)) {
-
-							// compute Delta
-							Point moveDelta = new Point(0, 0);
-							PolylineConnectionEx polyline = (PolylineConnectionEx) ((ConnectionEditPart) editPart).getFigure();
-							Point anchorPositionOnScreen;
-							if (((Message) message).getSendEvent().equals(nextEvent)) {
-								anchorPositionOnScreen = polyline.getTargetAnchor().getReferencePoint();
-							} else {
-								anchorPositionOnScreen = polyline.getSourceAnchor().getReferencePoint();
-							}
-							UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tanchorPositionOnScreen:\t" + anchorPositionOnScreen);
-
-							Point newLocation = new Point(0, createRequest.getLocation().y + AbstractExecutionSpecificationEditPart.DEFAUT_HEIGHT + deltaMoveAtCreationAndDeletion);
-							newLocation = SequenceUtil.getSnappedLocation(getHost(), newLocation);
-							UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tNew location to be set:\t" + newLocation);
-							moveDelta.y = newLocation.y - anchorPositionOnScreen.y;
-
-							// add move source and target request
-							UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tMoveDela:\t\t" + moveDelta.y);
-							moveTargetConnectionEditPart(null, moveDelta, compoundCommand, (ConnectionEditPart) editPart, senderList);
-							moveSourceConnectionEditPart(null, moveDelta, compoundCommand, (ConnectionEditPart) editPart, senderList);
+			// only first element need to be moved, other will follow
+			OccurrenceSpecification nextEvent = nextEventsFromPosition.get(0);
+			UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\tNext Event: " + nextEvent);
+
+			ArrayList<EditPart> senderList = SenderRequestUtils.getSenders(request);
+
+			List<?> connectionsAndChildren = new ArrayList<>();
+			connectionsAndChildren.addAll(((GraphicalEditPart) host).getSourceConnections());
+			connectionsAndChildren.addAll(((GraphicalEditPart) host).getTargetConnections());
+			connectionsAndChildren.addAll(((GraphicalEditPart) host).getChildren());
+
+			for (Object editPart : connectionsAndChildren) {
+				// move messages
+				if (editPart instanceof ConnectionEditPart) {
+					EObject message = ((View) ((AbstractMessageEditPart) editPart).getAdapter(View.class)).getElement();
+					if (message instanceof Message && null != ((Message) message).getSendEvent() && ((Message) message).getSendEvent().equals(nextEvent)
+							|| message instanceof Message && null != ((Message) message).getReceiveEvent() && ((Message) message).getReceiveEvent().equals(nextEvent)) {
+
+						// compute Delta
+						Point moveDelta = new Point(0, 0);
+						PolylineConnectionEx polyline = (PolylineConnectionEx) ((ConnectionEditPart) editPart).getFigure();
+						Point anchorPositionOnScreen;
+						if (((Message) message).getSendEvent().equals(nextEvent)) {
+							anchorPositionOnScreen = polyline.getTargetAnchor().getReferencePoint();
+						} else {
+							anchorPositionOnScreen = polyline.getSourceAnchor().getReferencePoint();
 						}
-					} else
-						// move execution specification
-						if (editPart instanceof AbstractExecutionSpecificationEditPart) {
-							EObject element = ((View) ((AbstractExecutionSpecificationEditPart) editPart).getAdapter(View.class)).getElement();
-
-							if (element instanceof ExecutionSpecification && null != ((ExecutionSpecification) element).getStart() && ((ExecutionSpecification) element).getStart().equals(nextEvent)) {
-								// compute Delta
-								Point moveDelta = new Point(0, 0);
-								Point figureLocation = ((AbstractExecutionSpecificationEditPart) editPart).getFigure().getBounds().getLocation();
-								UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tlocationOfFigure:\t" + figureLocation);
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tanchorPositionOnScreen:\t" + anchorPositionOnScreen);
 
-								Point newLocation = new Point(0, reqlocationOnScreen.y + AbstractExecutionSpecificationEditPart.DEFAUT_HEIGHT + deltaMoveAtCreationAndDeletion);
-								UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tNew location to be set:\t" + newLocation);
-								moveDelta.y = newLocation.y - figureLocation.y;
+						Point newLocation = new Point(0, createRequest.getLocation().y + AbstractExecutionSpecificationEditPart.DEFAUT_HEIGHT + deltaMoveAtCreationAndDeletion);
+						newLocation = SequenceUtil.getSnappedLocation(getHost(), newLocation);
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tNew location to be set:\t" + newLocation);
+						moveDelta.y = newLocation.y - anchorPositionOnScreen.y;
 
-								UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tMoveDela:\t\t" + moveDelta.y);
-								moveRoundedEditPart(null, moveDelta, compoundCommand, (EditPart) editPart, senderList);
-							}
-						}
+						// add move source and target request
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tMoveDela:\t\t" + moveDelta.y);
+						moveTargetConnectionEditPart(null, moveDelta, compoundCommand, (ConnectionEditPart) editPart, senderList);
+						moveSourceConnectionEditPart(null, moveDelta, compoundCommand, (ConnectionEditPart) editPart, senderList);
+					}
+				} else
+				// move execution specification
+				if (editPart instanceof AbstractExecutionSpecificationEditPart) {
+					EObject element = ((View) ((AbstractExecutionSpecificationEditPart) editPart).getAdapter(View.class)).getElement();
+
+					if (element instanceof ExecutionSpecification && null != ((ExecutionSpecification) element).getStart() && ((ExecutionSpecification) element).getStart().equals(nextEvent)) {
+						// compute Delta
+						Point moveDelta = new Point(0, 0);
+						Point figureLocation = ((AbstractExecutionSpecificationEditPart) editPart).getFigure().getBounds().getLocation();
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tlocationOfFigure:\t" + figureLocation);
+
+						Point newLocation = new Point(0, reqlocationOnScreen.y + AbstractExecutionSpecificationEditPart.DEFAUT_HEIGHT + deltaMoveAtCreationAndDeletion);
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tNew location to be set:\t" + newLocation);
+						moveDelta.y = newLocation.y - figureLocation.y;
+
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "\t\tMoveDela:\t\t" + moveDelta.y);
+						moveRoundedEditPart(null, moveDelta, compoundCommand, (EditPart) editPart, senderList);
+					}
 				}
 			}
 			if (!compoundCommand.isEmpty()) {
@@ -209,32 +211,32 @@ public class UpdateWeakReferenceForExecSpecEditPolicy extends UpdateWeakReferenc
 	 */
 	private Command getUpdateWeakRefForExecSpecResize(final ChangeBoundsRequest request) {
 		CompoundCommand compoundCommand = new CompoundCommand();
-		Point nextLocation = request.getLocation();
+		Point nextLocation = ((ChangeBoundsRequest) request).getLocation();
 		UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "+ MOVE at " + nextLocation + " of " + getHost());//$NON-NLS-1$ //$NON-NLS-2$
 		Rectangle locationAndSize = new PrecisionRectangle(getHostFigure().getBounds());
 		Point moveDelta = new Point(0, 0);
 		if (RequestConstants.REQ_MOVE.equals(request.getType())) {
-			moveDelta = request.getMoveDelta();
+			moveDelta = ((ChangeBoundsRequest) request).getMoveDelta();
 		} else if (RequestConstants.REQ_RESIZE.equals(request.getType())) {
-			moveDelta = new Point(0, request.getSizeDelta().height + request.getMoveDelta().y);
+			moveDelta = new Point(0, ((ChangeBoundsRequest) request).getSizeDelta().height + ((ChangeBoundsRequest) request).getMoveDelta().y);
 		}
 		if (moveDelta.y != 0 && mustMove) {
 			if (getHost() instanceof AbstractExecutionSpecificationEditPart) {
 				getHostFigure().translateToAbsolute(locationAndSize);
-				locationAndSize = request.getTransformedRectangle(locationAndSize);
+				locationAndSize = ((ChangeBoundsRequest) request).getTransformedRectangle(locationAndSize);
 			}
 			if (getHost().getEditPolicy(SequenceReferenceEditPolicy.SEQUENCE_REFERENCE) != null) {
 				SequenceReferenceEditPolicy references = (SequenceReferenceEditPolicy) getHost().getEditPolicy(SequenceReferenceEditPolicy.SEQUENCE_REFERENCE);
 				if (!SenderRequestUtils.isASender(request, getHost())) {
 
 					// Gets weak references
-					HashMap<EditPart, String> weakReferences = new HashMap<>();
+					HashMap<EditPart, String> weakReferences = new HashMap<EditPart, String>();
 					if ((moveDelta.y > 0 && mustMoveBelowAtMovingDown) || (moveDelta.y < 0 && mustMoveBelowAtMovingUp)) {
 						weakReferences.putAll(references.getWeakReferences());
 					}
 
 					for (Iterator<EditPart> iterator = weakReferences.keySet().iterator(); iterator.hasNext();) {
-						EditPart editPart = iterator.next();
+						EditPart editPart = (EditPart) iterator.next();
 						if (!SenderRequestUtils.isASender(request, editPart)) {
 							UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "+--> try to Move of " + moveDelta.y + " " + editPart);//$NON-NLS-1$
 							ArrayList<EditPart> senderList = SenderRequestUtils.getSenders(request);
@@ -273,7 +275,6 @@ public class UpdateWeakReferenceForExecSpecEditPolicy extends UpdateWeakReferenc
 		Point moveDelta = new Point(0, -hostConnectionEditPart.getPrimaryShape().getBounds().height);
 
 		if (moveDelta.y < 0) {
-
 			// get the edit policy of references
 			if (hostConnectionEditPart.getEditPolicy(SequenceReferenceEditPolicy.SEQUENCE_REFERENCE) != null) {
 				SequenceReferenceEditPolicy references = (SequenceReferenceEditPolicy) hostConnectionEditPart.getEditPolicy(SequenceReferenceEditPolicy.SEQUENCE_REFERENCE);
@@ -281,12 +282,12 @@ public class UpdateWeakReferenceForExecSpecEditPolicy extends UpdateWeakReferenc
 					CompoundCommand compoundCommand = new CompoundCommand();
 
 					// Gets weak references
-					HashMap<EditPart, String> weakReferences = new HashMap<>();
+					HashMap<EditPart, String> weakReferences = new HashMap<EditPart, String>();
 					weakReferences.putAll(references.getWeakReferences());
 
 					// for each weak reference move it
 					for (Iterator<EditPart> iterator = weakReferences.keySet().iterator(); iterator.hasNext();) {
-						EditPart editPart = iterator.next();
+						EditPart editPart = (EditPart) iterator.next();
 						if (!SenderRequestUtils.isASender(request, editPart)) {// avoid loop
 							UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG, "+--> try to Move " + editPart);//$NON-NLS-1$
 							ArrayList<EditPart> senderList = SenderRequestUtils.getSenders(request);
@@ -310,5 +311,3 @@ public class UpdateWeakReferenceForExecSpecEditPolicy extends UpdateWeakReferenc
 		return command;
 	}
 }
-
-
diff --git a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/ConnectMessageToGridEditPolicy.java b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/ConnectMessageToGridEditPolicy.java
index eefba57dc43..e802e340ab7 100644
--- a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/ConnectMessageToGridEditPolicy.java
+++ b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/ConnectMessageToGridEditPolicy.java
@@ -19,6 +19,7 @@ import org.eclipse.emf.common.notify.Notification;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.edit.command.SetCommand;
 import org.eclipse.emf.transaction.TransactionalEditingDomain;
+import org.eclipse.gef.EditPart;
 import org.eclipse.gmf.runtime.diagram.core.listener.DiagramEventBroker;
 import org.eclipse.gmf.runtime.diagram.core.listener.NotificationListener;
 import org.eclipse.gmf.runtime.diagram.ui.commands.SetBoundsCommand;
@@ -130,7 +131,7 @@ public class ConnectMessageToGridEditPolicy extends GraphicalEditPolicyEx implem
 						getDiagramEventBroker().addNotificationListener(rowSource, this);
 					}
 					// target
-					if (targetAnchor.getId() != null && !(targetAnchor.getId().equals(""))) {
+					if (null != targetEditPart && targetAnchor.getId() != null && !(targetAnchor.getId().equals(""))) {
 						Message m = (Message) connectionEditPart.resolveSemanticElement();
 						double absoluteY = computeAnchorPositionNotation(targetAnchor, targetEditPart);
 
@@ -197,35 +198,37 @@ public class ConnectMessageToGridEditPolicy extends GraphicalEditPolicyEx implem
 				if (sourceAnchor.getId() != null && !(sourceAnchor.getId().equals(""))) {
 					ConnectionEditPart connectionEditPart = (ConnectionEditPart) getHost();
 					Message m = (Message) connectionEditPart.resolveSemanticElement();
-					GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
-					int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
+					if (connectionEditPart.getSource() instanceof GraphicalEditPart) {
+						GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
+						int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
 
-					// Ensure that the target is always below the source
-					Edge edge = (Edge) connectionEditPart.getNotationView();
-					IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
-					GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
-					if (null != targetEditpart && null != targetAnchor) {
-						int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
-						if (targetAnchorY <= sourceAnchorY) {
-							sourceAnchorY = targetAnchorY - 1;
+						// Ensure that the target is always below the source
+						Edge edge = (Edge) connectionEditPart.getNotationView();
+						IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
+						EditPart targetEditpart = connectionEditPart.getTarget();
+						if (targetEditpart instanceof GraphicalEditPart && null != targetAnchor) {
+							int targetAnchorY = computeAnchorPositionNotation(targetAnchor, (GraphicalEditPart) targetEditpart);
+							if (targetAnchorY <= sourceAnchorY) {
+								sourceAnchorY = targetAnchorY - 1;
+							}
 						}
-					}
 
-					try {
-						GridManagementEditPolicy grilling = (GridManagementEditPolicy) diagramEditPart.getEditPolicy(GridManagementEditPolicy.GRID_MANAGEMENT);
-						if (grilling != null) {
-							if (rowSource == null) {
-								if (m.getSendEvent() == null) {
-									rowSource = grilling.createRowTolisten(sourceAnchorY, m);
-								} else {
-									rowSource = grilling.createRowTolisten(sourceAnchorY, m.getSendEvent());
+						try {
+							GridManagementEditPolicy grilling = (GridManagementEditPolicy) diagramEditPart.getEditPolicy(GridManagementEditPolicy.GRID_MANAGEMENT);
+							if (grilling != null) {
+								if (rowSource == null) {
+									if (m.getSendEvent() == null) {
+										rowSource = grilling.createRowTolisten(sourceAnchorY, m);
+									} else {
+										rowSource = grilling.createRowTolisten(sourceAnchorY, m.getSendEvent());
+									}
 								}
-							}
-							getDiagramEventBroker().addNotificationListener(rowSource, this);
+								getDiagramEventBroker().addNotificationListener(rowSource, this);
 
+							}
+						} catch (NoGrillElementFound e) {
+							UMLDiagramEditorPlugin.log.error(e);
 						}
-					} catch (NoGrillElementFound e) {
-						UMLDiagramEditorPlugin.log.error(e);
 					}
 				}
 			}
@@ -236,36 +239,38 @@ public class ConnectMessageToGridEditPolicy extends GraphicalEditPolicyEx implem
 				IdentityAnchor targetAnchor = (IdentityAnchor) notification.getNewValue();
 				if (targetAnchor.getId() != null && !(targetAnchor.getId().equals(""))) {
 					ConnectionEditPart connectionEditPart = (ConnectionEditPart) getHost();
-					GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
-					Message m = (Message) connectionEditPart.resolveSemanticElement();
-					int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
+					if (connectionEditPart.getTarget() instanceof GraphicalEditPart) {
+						GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
+						Message m = (Message) connectionEditPart.resolveSemanticElement();
+						int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
 
-					// Ensure that the target is always below the source
-					Edge edge = (Edge) connectionEditPart.getNotationView();
-					IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
-					GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
-					if (null != sourceEditpart && null != sourceAnchor) {
-						int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
-						if (targetAnchorY <= sourceAnchorY) {
-							targetAnchorY = sourceAnchorY + 1;
+						// Ensure that the target is always below the source
+						Edge edge = (Edge) connectionEditPart.getNotationView();
+						IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
+						EditPart sourceEditpart = connectionEditPart.getSource();
+						if (sourceEditpart instanceof GraphicalEditPart && null != sourceAnchor) {
+							int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, (GraphicalEditPart) sourceEditpart);
+							if (targetAnchorY <= sourceAnchorY) {
+								targetAnchorY = sourceAnchorY + 1;
+							}
 						}
-					}
 
 
-					try {
-						GridManagementEditPolicy grilling = (GridManagementEditPolicy) diagramEditPart.getEditPolicy(GridManagementEditPolicy.GRID_MANAGEMENT);
-						if (grilling != null) {
-							if (rowTarget == null) {
-								if (m.getReceiveEvent() == null) {
-									rowTarget = grilling.createRowTolisten(targetAnchorY, m);
-								} else {
-									rowTarget = grilling.createRowTolisten(targetAnchorY, m.getReceiveEvent());
+						try {
+							GridManagementEditPolicy grilling = (GridManagementEditPolicy) diagramEditPart.getEditPolicy(GridManagementEditPolicy.GRID_MANAGEMENT);
+							if (grilling != null) {
+								if (rowTarget == null) {
+									if (m.getReceiveEvent() == null) {
+										rowTarget = grilling.createRowTolisten(targetAnchorY, m);
+									} else {
+										rowTarget = grilling.createRowTolisten(targetAnchorY, m.getReceiveEvent());
+									}
 								}
+								getDiagramEventBroker().addNotificationListener(rowTarget, this);
 							}
-							getDiagramEventBroker().addNotificationListener(rowTarget, this);
+						} catch (NoGrillElementFound e) {
+							UMLDiagramEditorPlugin.log.error(e);
 						}
-					} catch (NoGrillElementFound e) {
-						UMLDiagramEditorPlugin.log.error(e);
 					}
 				}
 			}
@@ -275,23 +280,24 @@ public class ConnectMessageToGridEditPolicy extends GraphicalEditPolicyEx implem
 				Edge edge = (Edge) connectionEditPart.getNotationView();
 				if (edge.getSourceAnchor() != null && rowSource != null) {
 					IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
-					GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
-					int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
+					if (connectionEditPart.getSource() instanceof GraphicalEditPart) {
+						GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
+						int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
 
-					// Ensure that the target is always below the source
-					IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
-					GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
-					if (null != targetEditpart && null != targetAnchor) {
-						int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
-						if (targetAnchorY <= sourceAnchorY) {
-							sourceAnchorY = targetAnchorY - 1;
+						// Ensure that the target is always below the source
+						IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
+						EditPart targetEditpart = connectionEditPart.getTarget();
+						if (targetEditpart instanceof GraphicalEditPart && null != targetAnchor) {
+							int targetAnchorY = computeAnchorPositionNotation(targetAnchor, (GraphicalEditPart) targetEditpart);
+							if (targetAnchorY <= sourceAnchorY) {
+								sourceAnchorY = targetAnchorY - 1;
+							}
 						}
-					}
 
-					UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+--> SOURCE change for " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + sourceAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
-					updatePositionGridAxis((DecorationNode) rowSource, 0, sourceAnchorY);
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+--> SOURCE change for " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + sourceAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+						updatePositionGridAxis((DecorationNode) rowSource, 0, sourceAnchorY);
+					}
 				}
-
 			}
 
 			if (notification.getEventType() == Notification.SET && notification.getFeature().equals(NotationPackage.eINSTANCE.getEdge_Target())) {
@@ -300,21 +306,23 @@ public class ConnectMessageToGridEditPolicy extends GraphicalEditPolicyEx implem
 				Edge edge = (Edge) connectionEditPart.getNotationView();
 				if (edge.getTargetAnchor() != null && rowTarget != null) {
 					IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
-					GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
-					int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
+					if (connectionEditPart.getTarget() instanceof GraphicalEditPart) {
+						GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
+						int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
 
-					// Ensure that the target is always below the source
-					IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
-					GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
-					if (null != sourceEditpart && null != sourceAnchor) {
-						int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
-						if (targetAnchorY <= sourceAnchorY) {
-							targetAnchorY = sourceAnchorY + 1;
+						// Ensure that the target is always below the source
+						IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
+						EditPart sourceEditpart = connectionEditPart.getSource();
+						if (sourceEditpart instanceof GraphicalEditPart && null != sourceAnchor) {
+							int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, (GraphicalEditPart) sourceEditpart);
+							if (targetAnchorY <= sourceAnchorY) {
+								targetAnchorY = sourceAnchorY + 1;
+							}
 						}
-					}
 
-					UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+--> SOURCE change for " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + targetAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
-					updatePositionGridAxis((DecorationNode) rowTarget, 0, targetAnchorY);
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+--> SOURCE change for " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + targetAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+						updatePositionGridAxis((DecorationNode) rowTarget, 0, targetAnchorY);
+					}
 				}
 
 			}
@@ -326,39 +334,43 @@ public class ConnectMessageToGridEditPolicy extends GraphicalEditPolicyEx implem
 				Edge edge = (Edge) connectionEditPart.getNotationView();
 				if (notification.getNotifier().equals(edge.getSourceAnchor()) && rowSource != null) {
 					IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
-					GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
-					int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
+					if (connectionEditPart.getSource() instanceof GraphicalEditPart) {
+						GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
+						int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
 
-					// Ensure that the target is always below the source
-					IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
-					GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
-					if (null != targetEditpart && null != targetAnchor) {
-						int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
-						if (targetAnchorY <= sourceAnchorY) {
-							sourceAnchorY = targetAnchorY - 1;
+						// Ensure that the target is always below the source
+						IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
+						EditPart targetEditpart = connectionEditPart.getTarget();
+						if (targetEditpart instanceof GraphicalEditPart && null != targetAnchor) {
+							int targetAnchorY = computeAnchorPositionNotation(targetAnchor, (GraphicalEditPart) targetEditpart);
+							if (targetAnchorY <= sourceAnchorY) {
+								sourceAnchorY = targetAnchorY - 1;
+							}
 						}
-					}
 
-					UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+--> SOURCE change for " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + sourceAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
-					updatePositionGridAxis((DecorationNode) rowSource, 0, sourceAnchorY);
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+--> SOURCE change for " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + sourceAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+						updatePositionGridAxis((DecorationNode) rowSource, 0, sourceAnchorY);
+					}
 				}
 				if (notification.getNotifier().equals(edge.getTargetAnchor()) && rowTarget != null) {
-					GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
-					IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
-					int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
+					if (connectionEditPart.getTarget() instanceof GraphicalEditPart) {
+						GraphicalEditPart targetEditpart = (GraphicalEditPart) connectionEditPart.getTarget();
+						IdentityAnchor targetAnchor = (IdentityAnchor) edge.getTargetAnchor();
+						int targetAnchorY = computeAnchorPositionNotation(targetAnchor, targetEditpart);
 
-					// Ensure that the target is always below the source
-					IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
-					GraphicalEditPart sourceEditpart = (GraphicalEditPart) connectionEditPart.getSource();
-					if (null != sourceEditpart && null != sourceAnchor) {
-						int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, sourceEditpart);
-						if (targetAnchorY <= sourceAnchorY) {
-							targetAnchorY = sourceAnchorY + 1;
+						// Ensure that the target is always below the source
+						IdentityAnchor sourceAnchor = (IdentityAnchor) edge.getSourceAnchor();
+						EditPart sourceEditpart = connectionEditPart.getSource();
+						if (sourceEditpart instanceof GraphicalEditPart && null != sourceAnchor) {
+							int sourceAnchorY = computeAnchorPositionNotation(sourceAnchor, (GraphicalEditPart) sourceEditpart);
+							if (targetAnchorY <= sourceAnchorY) {
+								targetAnchorY = sourceAnchorY + 1;
+							}
 						}
-					}
 
-					UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+-->TARGET change " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + targetAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
-					updatePositionGridAxis((DecorationNode) rowTarget, 0, targetAnchorY);
+						UMLDiagramEditorPlugin.log.trace(LogOptions.SEQUENCE_DEBUG_REFERENCEGRID, "+-->TARGET change " + ((NamedElement) connectionEditPart.resolveSemanticElement()).getName() + " to " + targetAnchorY + " ");//$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+						updatePositionGridAxis((DecorationNode) rowTarget, 0, targetAnchorY);
+					}
 				}
 
 			}
diff --git a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/GridManagementEditPolicy.java b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/GridManagementEditPolicy.java
index 70a8dd2aeb1..a459e048731 100644
--- a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/GridManagementEditPolicy.java
+++ b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/GridManagementEditPolicy.java
@@ -70,7 +70,7 @@ public class GridManagementEditPolicy extends GraphicalEditPolicyEx implements A
 	public static String COLUMN = "COLUMN_"; //$NON-NLS-1$
 	public static String ROW = "ROW_"; //$NON-NLS-1$
 
-	public int threshold = 5;
+	public static int threshold = 5;
 
 	/**
 	 * @return the threshold
diff --git a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/LifeLineGraphicalNodeEditPolicy.java b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/LifeLineGraphicalNodeEditPolicy.java
index c3256ec48c0..2919ae9914d 100644
--- a/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/LifeLineGraphicalNodeEditPolicy.java
+++ b/plugins/uml/diagram/org.eclipse.papyrus.uml.diagram.sequence/custom-src/org/eclipse/papyrus/uml/diagram/sequence/referencialgrilling/LifeLineGraphicalNodeEditPolicy.java
@@ -131,6 +131,9 @@ public class LifeLineGraphicalNodeEditPolicy extends DefaultGraphicalNodeEditPol
 			if (location != displayEvent.getRealEventLocation(location)) {
 				request.setLocation(displayEvent.getRealEventLocation(location));
 			}
+		} else if (os instanceof MessageEnd) {
+			// Event of Exec Spec have been already replaced. Only one message can be related to start or finish.
+			return UnexecutableCommand.INSTANCE;
 		}
 
 		return super.getConnectionCreateCommand(request);
@@ -383,8 +386,8 @@ public class LifeLineGraphicalNodeEditPolicy extends DefaultGraphicalNodeEditPol
 			request.setExtendedData(extendedData);
 		}
 		// add a param if we must replace an event of the execution specification
-		OccurrenceSpecification os = displayEvent.getActionExecutionSpecificationEvent(getHostFigure().getParent().getParent(), ((CreateRequest) request).getLocation());
-		if (os != null) {
+		OccurrenceSpecification os = displayEvent.getActionExecutionSpecificationEvent(null, ((CreateRequest) request).getLocation());
+		if (os instanceof ExecutionOccurrenceSpecification) {
 			Map<String, Object> extendedData = request.getExtendedData();
 			extendedData.put(org.eclipse.papyrus.uml.service.types.utils.SequenceRequestConstant.MESSAGE_RECEIVEEVENT_REPLACE_EXECUTIONEVENT, os);
 			request.setExtendedData(extendedData);
@@ -600,6 +603,7 @@ public class LifeLineGraphicalNodeEditPolicy extends DefaultGraphicalNodeEditPol
 	 */
 	private boolean isAllowedMessageEnd(CreateConnectionViewAndElementRequest request) {
 		Boolean allowed = true;
+		// check if target is lower than source
 		if (!precisionMode) {
 			Point targetLocation = request.getLocation();
 			Map<String, Object> extendedData = request.getExtendedData();
@@ -608,6 +612,11 @@ public class LifeLineGraphicalNodeEditPolicy extends DefaultGraphicalNodeEditPol
 				allowed &= isTargetLowerThanSource(SequenceUtil.getSnappedLocation(getHost(), (Point) sourceLocation), targetLocation);
 			}
 		}
+
+		// Check if we are in a execution event, and if the event have been already be replaced, we can't allow it.
+		OccurrenceSpecification os = displayEvent.getActionExecutionSpecificationEvent(null, ((CreateRequest) request).getLocation());
+		allowed &= !(null != os && !(os instanceof ExecutionOccurrenceSpecification));
+
 		return allowed;
 	}