com.yworks.yfiles.view.input

Class PortRelocationHandle

java.lang.Object

com.yworks.yfiles.view.input.PortRelocationHandle

All Implemented Interfaces:

IDragHandler, IHandle

public class PortRelocationHandle
extends Object
implements IHandle

A sophisticated implementation of the IHandle interface that lets the user change an edge's source and target port.

This handle will move one of the edge's end points visually to another IPort or IPortCandidate and upon finalization of the gesture will set the new ports for the edge. This class heavily relies on the implementation of the IEdgeReconnectionPortCandidateProvider that is queried from the IEdge this handle is acting on.

See Also:

getPortCandidates(IInputModeContext, IEdge, boolean), EdgeDecorator.getEdgeReconnectionPortCandidateProviderDecorator()

Constructor Summary

Constructors

Constructor and Description
PortRelocationHandle(IGraph graph, IEdge edge, boolean sourceEnd) Creates a new instance of the PortRelocationHandle class.

Method Summary

Modifier and Type	Method and Description
void	cancelDrag(IInputModeContext context, PointD originalLocation) Called by clients to indicate that the dragging has been canceled by the user.
protected ICanvasObjectDescriptor	createCurrentPortCandidateDescriptor() Factory method that creates the ICanvasObjectDescriptor that will be used to paint the "current" IPortCandidate.
protected SimpleEdge	createDummyEdge(IEdge edge) Factory method that creates the dummy edge that will be shown during the drag operation.
protected IVisualCreator	createDummyEdgeVisualCreator(SimpleEdge dummy) Factory method that creates a dummy paintable for the dummy edge during the drag operation.
protected IPortCandidate	createExistingPortCandidate(IPort port) Factory method that creates the candidate for the existing port.
protected ICanvasObjectDescriptor	createPortCandidateDescriptor() Factory method that creates the ICanvasObjectDescriptor that will be used to paint the IPortCandidates.
void	dragFinished(IInputModeContext context, PointD originalLocation, PointD newLocation) Called by clients to indicate that the repositioning has just been finished.
protected IPortCandidate	getClosestCandidate(IInputModeContext context, PointD location, Iterable<IPortCandidate> candidates) Finds the closest candidate from the given set of candidates.
Cursor	getCursor() Provides the cursor to display when the mouse hovers over or drags this handle.
protected SimpleEdge	getDummyEdge() Gets the dummy edge this instance uses during the edit.
protected IEdge	getEdge() Gets the edge this instance acts upon.
protected IGraph	getGraph(IInputModeContext context) Gets the graph to use from the context.
protected IInputModeContext	getInputModeContext() Gets the context to operate on.
IPoint	getLocation() Returns a view of the location of the item.
double	getMaximumSnapDistance() Gets the maximum distance the pointer may be away of a candidate in order to be snapped to the candidate.
protected IPort	getPort(IInputModeContext context, IPortCandidate portCandidate, PointD suggestedLocation) Callback used during dragFinished(IInputModeContext, PointD, PointD) to actually get the new port from the chosen candidate.
IEventRecognizer	getPortCandidateResolutionRecognizer() Gets the event recognizer that determines whether a dynamic port candidate should be resolved.
protected Iterable<IPortCandidate>	getPortCandidates(IInputModeContext context, IEdge edge, boolean sourcePort) Gets the possible candidates for the given edge.
HandleTypes	getType() Returns the type of the handle that can be used by the rendering engine to render types differently.
void	handleMove(IInputModeContext context, PointD originalLocation, PointD newLocation) Called by clients to indicate that the element has been dragged and its position should be updated.
protected void	hideOriginalEdge(IInputModeContext context, IEdge edge) Hides the original edge that during the drag operation.
void	initializeDrag(IInputModeContext context) Called by clients to indicate that the element is going to be dragged.
boolean	isCyclicPortDependenciesAllowed() Determines whether or not cyclic port dependencies are allowed.
boolean	isDummyEdgeDisplayEnabled() Gets a value indicating whether to show a dummy edge during the drag operation.
boolean	isEdgeToEdgeConnectionsAllowed() Determines whether or not edges are allowed to connect to other edges.
boolean	isExistingPortAddingEnabled() Gets a property that determines whether the existing port should be available as a possible port candidate, too.
protected boolean	isPortCandidateResolutionEnabled(IInputModeContext context) Determines whether port candidate resolution is enabled for the current gesture.
boolean	isPortCandidateResolvingEnabled() Gets a value indicating whether a dynamic port candidate should be resolved for the current mouse location.
boolean	isShowingHitPortOwnerCandidatesOnlyEnabled() Gets a value indicating whether to show the candidates of hit IPortOwners only.
protected boolean	isSourceEnd() Gets a value indicating whether the source end of the edge is handled by this instance.
protected IPortCandidate	resolveCandidate(IInputModeContext context, IPortCandidate portCandidate, PointD location) Tries to resolve a dynamic port candidate for the given location.
protected void	setClosestCandidate(IPortCandidate portCandidate) Updates the closest candidate for visual feedback.
void	setCursor(Cursor value) Provides the cursor to display when the mouse hovers over or drags this handle.
void	setCyclicPortDependenciesAllowed(boolean value) Determines whether or not cyclic port dependencies are allowed.
void	setDummyEdgeDisplayEnabled(boolean value) Sets a value indicating whether to show a dummy edge during the drag operation.
void	setEdgeToEdgeConnectionsAllowed(boolean value) Determines whether or not edges are allowed to connect to other edges.
void	setExistingPortAddingEnabled(boolean value) Sets a property that determines whether the existing port should be available as a possible port candidate, too.
protected void	setInputModeContext(IInputModeContext value) Sets the context to operate on.
void	setMaximumSnapDistance(double value) Sets the maximum distance the pointer may be away of a candidate in order to be snapped to the candidate.
protected void	setPort(IInputModeContext context, IEdge edge, boolean setSourcePort, IPortCandidate portCandidate, PointD suggestedLocation) Callback that is triggered by dragFinished(IInputModeContext, PointD, PointD) to actually change the port.
void	setPortCandidateResolutionRecognizer(IEventRecognizer value) Sets the event recognizer that determines whether a dynamic port candidate should be resolved.
void	setPortCandidateResolvingEnabled(boolean value) Sets a value indicating whether a dynamic port candidate should be resolved for the current mouse location.
protected void	setPorts(IInputModeContext context, IEdge edge, IPort sourcePort, IPort targetPort) Finally sets the ports for the edge to the new values.
protected void	setPosition(PointD location) Updates the position of the handle.
void	setShowingHitPortOwnerCandidatesOnlyEnabled(boolean value) Sets a value indicating whether to show the candidates of hit IPortOwners only.
protected void	setToPortCandidate(SimpleEdge dummy, boolean source, IPortCandidate portCandidate) Updates the dummy edge's visual appearance to reflect the new port candidate.
void	setType(HandleTypes value) Returns the type of the handle that can be used by the rendering engine to render types differently.
protected void	unhideOriginalEdge(IEdge edge, CanvasControl canvas) Unhides the original edge that was hidden during the drag operation.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PortRelocationHandle

public PortRelocationHandle(IGraph graph,
                            IEdge edge,
                            boolean sourceEnd)

Creates a new instance of the PortRelocationHandle class.

Parameters:

graph - The graph or null. If the graph instance is not specified, the handle will try to receive the graph from the IInputModeContext it is passed in during initializeDrag(IInputModeContext).

edge - The edge.

sourceEnd - if set to true the source end will be subject to relocation, otherwise it will be the target port.

Method Detail

cancelDrag

public void cancelDrag(IInputModeContext context,
                       PointD originalLocation)

Description copied from interface: IDragHandler

Called by clients to indicate that the dragging has been canceled by the user.

This method may be called after the initial IDragHandler.initializeDrag(IInputModeContext) and zero or more invocations of IDragHandler.handleMove(IInputModeContext, PointD, PointD). Implementations should reset the position of the items they modify to their initial state. Alternatively to this method the IDragHandler.dragFinished(IInputModeContext, PointD, PointD) method might be called.

Specified by:

cancelDrag in interface IDragHandler

Parameters:

context - The context to retrieve information about the drag from.

originalLocation - The value of the coordinate of the Location property at the time of IDragHandler.initializeDrag(IInputModeContext).

createCurrentPortCandidateDescriptor

protected ICanvasObjectDescriptor createCurrentPortCandidateDescriptor()

Factory method that creates the ICanvasObjectDescriptor that will be used to paint the "current" IPortCandidate.

Returns:

The descriptor to use for the rendering in the CanvasControl.

createDummyEdge

protected final SimpleEdge createDummyEdge(IEdge edge)

Factory method that creates the dummy edge that will be shown during the drag operation.

Parameters:

edge - The edge to be represented by the dummy edge.

Returns:

The dummy edge instance to use.

See Also:

isDummyEdgeDisplayEnabled()

createDummyEdgeVisualCreator

protected IVisualCreator createDummyEdgeVisualCreator(SimpleEdge dummy)

Factory method that creates a dummy paintable for the dummy edge during the drag operation.

Parameters:

dummy - The dummy to create a paintable for.

Returns:

A paintable that shows the dummy.

See Also:

isDummyEdgeDisplayEnabled()

createExistingPortCandidate

protected IPortCandidate createExistingPortCandidate(IPort port)

Factory method that creates the candidate for the existing port.

Parameters:

port - The port to create a candidate for.

Returns:

The candidate or null.

See Also:

getPortCandidates(IInputModeContext, IEdge, boolean), isExistingPortAddingEnabled()

createPortCandidateDescriptor

protected ICanvasObjectDescriptor createPortCandidateDescriptor()

Factory method that creates the ICanvasObjectDescriptor that will be used to paint the IPortCandidates.

Returns:

The descriptor to use for the rendering in the CanvasControl.

dragFinished

public void dragFinished(IInputModeContext context,
                         PointD originalLocation,
                         PointD newLocation)

Description copied from interface: IDragHandler

Called by clients to indicate that the repositioning has just been finished.

This method may be called after the initial IDragHandler.initializeDrag(IInputModeContext) and zero or more invocations of IDragHandler.handleMove(IInputModeContext, PointD, PointD). Alternatively to this method the IDragHandler.cancelDrag(IInputModeContext, PointD) method might be called.

Specified by:

dragFinished in interface IDragHandler

Parameters:

context - The context to retrieve information about the drag from.

originalLocation - The value of the Location property at the time of IDragHandler.initializeDrag(IInputModeContext).

newLocation - The coordinates in the world coordinate system that the client wants the handle to be at. Depending on the implementation the Location may or may not be modified to reflect the new value. This is the same value as delivered in the last invocation of IDragHandler.handleMove(IInputModeContext, PointD, PointD)

getClosestCandidate

protected IPortCandidate getClosestCandidate(IInputModeContext context,
                                             PointD location,
                                             Iterable<IPortCandidate> candidates)

Finds the closest candidate from the given set of candidates.

Parameters:

context - The context in for which the closest handle candidate is sought.

location - The location for which to find a candidate.

candidates - The list of possible candidates.

Returns:

The closes candidate or null.

getCursor

public Cursor getCursor()

Description copied from interface: IHandle

Provides the cursor to display when the mouse hovers over or drags this handle.

Specified by:

getCursor in interface IHandle

Returns:

The Cursor.

getDummyEdge

protected final SimpleEdge getDummyEdge()

Gets the dummy edge this instance uses during the edit.

Returns:

The dummy edge.

See Also:

isDummyEdgeDisplayEnabled()

getEdge

protected final IEdge getEdge()

Gets the edge this instance acts upon.

Returns:

The edge.

getGraph

protected IGraph getGraph(IInputModeContext context)

Gets the graph to use from the context.

Parameters:

context - The input mode context.

Returns:

A graph instance or null.

getInputModeContext

protected final IInputModeContext getInputModeContext()

Gets the context to operate on.

Returns:

The InputModeContext.

See Also:

setInputModeContext(IInputModeContext)

getLocation

public IPoint getLocation()

Returns a view of the location of the item.

This implementation returns this.

Specified by:

getLocation in interface IDragHandler

Returns:

The Location.

getMaximumSnapDistance

public final double getMaximumSnapDistance()

Gets the maximum distance the pointer may be away of a candidate in order to be snapped to the candidate.

The distance is measured in view coordinates. The default value is 50.0.

Returns:

The MaximumSnapDistance.

See Also:

setMaximumSnapDistance(double)

getPort

protected IPort getPort(IInputModeContext context,
                        IPortCandidate portCandidate,
                        PointD suggestedLocation)

Callback used during dragFinished(IInputModeContext, PointD, PointD) to actually get the new port from the chosen candidate.

This implementation returns the result of IPortCandidate.createPort(IInputModeContext) or calls IGraph.addPort(IPortOwner, com.yworks.yfiles.graph.portlocationmodels.IPortLocationModelParameter, com.yworks.yfiles.graph.styles.IPortStyle, Object) if the result was null.

Parameters:

portCandidate - The candidate to get a port instance from.

suggestedLocation - The suggested location for the port.

Returns:

A non-null port instance.

See Also:

setPorts(IInputModeContext, IEdge, IPort, IPort)

getPortCandidateResolutionRecognizer

public final IEventRecognizer getPortCandidateResolutionRecognizer()

Gets the event recognizer that determines whether a dynamic port candidate should be resolved.

Note that this property has no effect if PortCandidateResolvingEnabled is set to false.

By default this is set to IEventRecognizer.SHIFT_PRESSED.

Returns:

The PortCandidateResolutionRecognizer.

See Also:

setPortCandidateResolutionRecognizer(IEventRecognizer)

getPortCandidates

protected Iterable<IPortCandidate> getPortCandidates(IInputModeContext context,
                                                     IEdge edge,
                                                     boolean sourcePort)

Gets the possible candidates for the given edge.

This implementation uses the IEdgeReconnectionPortCandidateProvider from the edge's ILookup.lookup(Class) to retrieve the candidate sets. If ExistingPortAddingEnabled is enabled, the existing port will be part of the candidates.

Parameters:

context - The context that is used to retrieve the candidates for.

edge - The edge.

sourcePort - Whether to look for source port candidates.

Returns:

A non-null enumerable over the candidates.

getType

public HandleTypes getType()

Description copied from interface: IHandle

Returns the type of the handle that can be used by the rendering engine to render types differently.

Specified by:

getType in interface IHandle

Returns:

The Type.

handleMove

public void handleMove(IInputModeContext context,
                       PointD originalLocation,
                       PointD newLocation)

Description copied from interface: IDragHandler

Called by clients to indicate that the element has been dragged and its position should be updated.

This method may be called more than once after an initial IDragHandler.initializeDrag(IInputModeContext) and will the final call will be followed by either one IDragHandler.dragFinished(IInputModeContext, PointD, PointD) or one IDragHandler.cancelDrag(IInputModeContext, PointD) call.

Specified by:

handleMove in interface IDragHandler

Parameters:

context - The context to retrieve information about the drag from.

originalLocation - The value of the Location property at the time of IDragHandler.initializeDrag(IInputModeContext).

newLocation - The coordinates in the world coordinate system that the client wants the handle to be at. Depending on the implementation the Location may or may not be modified to reflect the new value.

hideOriginalEdge

protected void hideOriginalEdge(IInputModeContext context,
                                IEdge edge)

Hides the original edge that during the drag operation.

Parameters:

edge - The edge to hide.

context - The context to get the canvas the edge should be hidden from.

See Also:

unhideOriginalEdge(IEdge, CanvasControl), isDummyEdgeDisplayEnabled()

initializeDrag

public void initializeDrag(IInputModeContext context)

Description copied from interface: IDragHandler

Called by clients to indicate that the element is going to be dragged.

This call will be followed by one or more calls to IDragHandler.handleMove(IInputModeContext, PointD, PointD), and a final IDragHandler.dragFinished(IInputModeContext, PointD, PointD) or IDragHandler.cancelDrag(IInputModeContext, PointD).

Specified by:

initializeDrag in interface IDragHandler

Parameters:

context - The context to retrieve information about the drag from.

isCyclicPortDependenciesAllowed

public final boolean isCyclicPortDependenciesAllowed()

Determines whether or not cyclic port dependencies are allowed.

If edge to edge connections are allowed by this instance, this property determines whether getClosestCandidate(IInputModeContext, PointD, Iterable)s are will yield candidates that would result in the edge being modified would create a cyclic dependency. The default is false.

Returns:

The CyclicPortDependenciesAllowed.

See Also:

setCyclicPortDependenciesAllowed(boolean)

isDummyEdgeDisplayEnabled

public final boolean isDummyEdgeDisplayEnabled()

Gets a value indicating whether to show a dummy edge during the drag operation.

The default is true.

Returns:

The DummyEdgeDisplayEnabled.

See Also:

setDummyEdgeDisplayEnabled(boolean)

isEdgeToEdgeConnectionsAllowed

public final boolean isEdgeToEdgeConnectionsAllowed()

Determines whether or not edges are allowed to connect to other edges.

The default is true.

Returns:

The EdgeToEdgeConnectionsAllowed.

See Also:

setEdgeToEdgeConnectionsAllowed(boolean)

isExistingPortAddingEnabled

public final boolean isExistingPortAddingEnabled()

Gets a property that determines whether the existing port should be available as a possible port candidate, too.

The default is true. If this property is set to false, getPortCandidates(IInputModeContext, IEdge, boolean) will return only the ports provided by the IPortCandidateProvider in the node's lookup.

Returns:

The ExistingPortAddingEnabled.

See Also:

setExistingPortAddingEnabled(boolean)

isPortCandidateResolutionEnabled

protected boolean isPortCandidateResolutionEnabled(IInputModeContext context)

Determines whether port candidate resolution is enabled for the current gesture.

This implementation checks whether the the parent input mode is an instance of HandleInputMode, the PortCandidateResolutionRecognizer recognizes its Mouse2DEvent, and the CurrentHandle's location is equal to this Location.

Parameters:

context - The context to inspect.

Returns:

true if port candidates may be resolved; false otherwise.

isPortCandidateResolvingEnabled

public final boolean isPortCandidateResolvingEnabled()

Gets a value indicating whether a dynamic port candidate should be resolved for the current mouse location.

By default this feature is enabled and the PortCandidateResolutionRecognizer is configured so that the resolution mechanism is used if the user holds the shift modifier during the gesture.

Returns:

The PortCandidateResolvingEnabled.

See Also:

getPortCandidateResolutionRecognizer(), resolveCandidate(IInputModeContext, IPortCandidate, PointD), setPortCandidateResolvingEnabled(boolean)

isShowingHitPortOwnerCandidatesOnlyEnabled

public final boolean isShowingHitPortOwnerCandidatesOnlyEnabled()

Gets a value indicating whether to show the candidates of hit IPortOwners only.

Returns:

true if only candidates of hit nodes and edges are shown; false otherwise.

See Also:

setShowingHitPortOwnerCandidatesOnlyEnabled(boolean)

isSourceEnd

protected final boolean isSourceEnd()

Gets a value indicating whether the source end of the edge is handled by this instance.

Returns:

true if the source end is handled; false otherwise.

resolveCandidate

protected IPortCandidate resolveCandidate(IInputModeContext context,
                                          IPortCandidate portCandidate,
                                          PointD location)

Tries to resolve a dynamic port candidate for the given location.

Parameters:

context - The context in which the candidate is resolved.

portCandidate - The candidate.

location - The current location.

Returns:

A candidate.

setClosestCandidate

protected void setClosestCandidate(IPortCandidate portCandidate)

Updates the closest candidate for visual feedback.

setCursor

public void setCursor(Cursor value)

Provides the cursor to display when the mouse hovers over or drags this handle.

Parameters:

value - The Cursor to set.

See Also:

getCursor()

setCyclicPortDependenciesAllowed

public final void setCyclicPortDependenciesAllowed(boolean value)

Determines whether or not cyclic port dependencies are allowed.

If edge to edge connections are allowed by this instance, this property determines whether getClosestCandidate(IInputModeContext, PointD, Iterable)s are will yield candidates that would result in the edge being modified would create a cyclic dependency. The default is false.

Parameters:

value - The CyclicPortDependenciesAllowed to set.

See Also:

isCyclicPortDependenciesAllowed()

setDummyEdgeDisplayEnabled

public final void setDummyEdgeDisplayEnabled(boolean value)

Sets a value indicating whether to show a dummy edge during the drag operation.

The default is true.

Parameters:

value - The DummyEdgeDisplayEnabled to set.

See Also:

isDummyEdgeDisplayEnabled()

setEdgeToEdgeConnectionsAllowed

public final void setEdgeToEdgeConnectionsAllowed(boolean value)

Determines whether or not edges are allowed to connect to other edges.

The default is true.

Parameters:

value - The EdgeToEdgeConnectionsAllowed to set.

See Also:

isEdgeToEdgeConnectionsAllowed()

setExistingPortAddingEnabled

public final void setExistingPortAddingEnabled(boolean value)

Sets a property that determines whether the existing port should be available as a possible port candidate, too.

The default is true. If this property is set to false, getPortCandidates(IInputModeContext, IEdge, boolean) will return only the ports provided by the IPortCandidateProvider in the node's lookup.

Parameters:

value - The ExistingPortAddingEnabled to set.

See Also:

isExistingPortAddingEnabled()

setInputModeContext

protected final void setInputModeContext(IInputModeContext value)

Sets the context to operate on.

Parameters:

value - The InputModeContext to set.

See Also:

getInputModeContext()

setMaximumSnapDistance

public final void setMaximumSnapDistance(double value)

Sets the maximum distance the pointer may be away of a candidate in order to be snapped to the candidate.

The distance is measured in view coordinates. The default value is 50.0.

Parameters:

value - The MaximumSnapDistance to set.

See Also:

getMaximumSnapDistance()

setPort

protected void setPort(IInputModeContext context,
                       IEdge edge,
                       boolean setSourcePort,
                       IPortCandidate portCandidate,
                       PointD suggestedLocation)

Callback that is triggered by dragFinished(IInputModeContext, PointD, PointD) to actually change the port.

Parameters:

context - The context.

edge - The edge to change ports.

setSourcePort - Whether to set the source port. false for target ports.

portCandidate - The candidate that has been chosen.

suggestedLocation - The suggested location for the port.

setPortCandidateResolutionRecognizer

public final void setPortCandidateResolutionRecognizer(IEventRecognizer value)

Sets the event recognizer that determines whether a dynamic port candidate should be resolved.

Note that this property has no effect if PortCandidateResolvingEnabled is set to false.

By default this is set to IEventRecognizer.SHIFT_PRESSED.

Parameters:

value - The PortCandidateResolutionRecognizer to set.

See Also:

getPortCandidateResolutionRecognizer()

setPortCandidateResolvingEnabled

public final void setPortCandidateResolvingEnabled(boolean value)

Sets a value indicating whether a dynamic port candidate should be resolved for the current mouse location.

By default this feature is enabled and the PortCandidateResolutionRecognizer is configured so that the resolution mechanism is used if the user holds the shift modifier during the gesture.

Parameters:

value - The PortCandidateResolvingEnabled to set.

See Also:

getPortCandidateResolutionRecognizer(), resolveCandidate(IInputModeContext, IPortCandidate, PointD), isPortCandidateResolvingEnabled()

setPorts

protected void setPorts(IInputModeContext context,
                        IEdge edge,
                        IPort sourcePort,
                        IPort targetPort)

Finally sets the ports for the edge to the new values.

Parameters:

context - The context in which the ports are set.

edge - The edge to set the ports for.

sourcePort - The (possibly) new source port.

targetPort - The (possibly) new target port.

setPosition

protected void setPosition(PointD location)

Updates the position of the handle.

Parameters:

location - The new location of the handle.

setShowingHitPortOwnerCandidatesOnlyEnabled

public final void setShowingHitPortOwnerCandidatesOnlyEnabled(boolean value)

Sets a value indicating whether to show the candidates of hit IPortOwners only.

Parameters:

value - true if only candidates of hit nodes and edges are shown; false otherwise.

See Also:

isShowingHitPortOwnerCandidatesOnlyEnabled()

setToPortCandidate

protected void setToPortCandidate(SimpleEdge dummy,
                                  boolean source,
                                  IPortCandidate portCandidate)

Updates the dummy edge's visual appearance to reflect the new port candidate.

Parameters:

dummy - The dummy edge.

source - Whether to update the source or target port.

portCandidate - The new candidate to indicate.

setType

public void setType(HandleTypes value)

Returns the type of the handle that can be used by the rendering engine to render types differently.

Parameters:

value - The Type to set.

See Also:

getType()

unhideOriginalEdge

protected void unhideOriginalEdge(IEdge edge,
                                  CanvasControl canvas)

Unhides the original edge that was hidden during the drag operation.

Parameters:

edge - The edge to unhide.

canvas - The canvas the edge was hidden from.

See Also:

hideOriginalEdge(IInputModeContext, IEdge), isDummyEdgeDisplayEnabled()