Package org.eclipse.gef.dnd
Class AbstractTransferDropTargetListener
- java.lang.Object
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- org.eclipse.gef.dnd.AbstractTransferDropTargetListener
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- All Implemented Interfaces:
java.util.EventListener,TransferDropTargetListener,TransferDropTargetListener,DropTargetListener,SWTEventListener
- Direct Known Subclasses:
TemplateTransferDropTargetListener
public abstract class AbstractTransferDropTargetListener extends java.lang.Object implements TransferDropTargetListener
An abstract implementation of TransferDropTargetListener for use withEditPartViewers. The Viewer'sControlshould be the Drop target. In order to communicate with EditParts in a consistent way, DropTargetEvents are processed intoRequests.Dropping is inherently a targeting interaction. This class handles calculating the target EditPart. It also handles common targeting behavior, such as interacting with the target EditPart or its ancestors to achieve things like auto-scroll/auto-expose.
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Constructor Summary
Constructors Constructor Description AbstractTransferDropTargetListener(EditPartViewer viewer)Constructs a new AbstractTransferDropTargetListener and sets the EditPartViewer.AbstractTransferDropTargetListener(EditPartViewer viewer, Transfer xfer)Constructs a new AbstractTransferDropTargetListener and sets the EditPartViewer and Transfer.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected RequestcreateTargetRequest()Creates and returns theRequestthat will be sent to the targeted EditPart.voiddragEnter(DropTargetEvent event)Stores the information about the current DropTargetEvent.voiddragLeave(DropTargetEvent event)Stores the information about the current DropTargetEvent and then callsunload().voiddragOperationChanged(DropTargetEvent event)Stores the information about the current DropTargetEvent and then callshandleDragOperationChanged().voiddragOver(DropTargetEvent event)Stores the information about the current DropTargetEvent and then callshandleDragOver().voiddrop(DropTargetEvent event)Stores the information about the current DropTargetEvent and then callshandleDrop(), followed byunload().voiddropAccept(DropTargetEvent event)Stores the currentDropTargetEventand does nothing.protected voideraseTargetFeedback()CallseraseTargetFeedback(Request)on the current target, using the target Request.protected CommandgetCommand()Returns the current command from the target EditPart.DropTargetEventgetCurrentEvent()Returns the currentDropTargetEvent.protected org.eclipse.draw2d.geometry.PointgetDropLocation()Returns the current mouse location, as aPoint.protected java.util.CollectiongetExclusionSet()Returns a Collection ofEditPartsthat are to be excluded when searching for the target EditPart.protected EditPartgetTargetEditPart()Returns the current targetEditPart.protected RequestgetTargetRequest()Returns the targetRequest.TransfergetTransfer()protected EditPartViewergetViewer()Returns theEditPartViewerthat is the target of the drop.protected voidhandleDragOperationChanged()Called when the user changes the Drag operation.protected voidhandleDragOver()Called whenever the User drags over the target.protected voidhandleDrop()Updates the target Request and target EditPart, and performs the drop.protected voidhandleEnteredEditPart()Called when a new target EditPart has been entered.protected voidhandleExitingEditPart()Called as the current target EditPart is being exited.protected voidhandleHover()Called when the mouse hovers during drag and drop.protected voidhandleHoverStop()Called when the mouse resumes motion after having hovered.booleanisEnabled(DropTargetEvent event)Returnstrueif this TransferDropTargetListener is enabled for the specifiedDropTargetEvent.protected booleanisEnablementDeterminedByCommand()ReturnstrueifisEnabled(DropTargetEvent)is determined by asking the potential target for a Command.protected voidsetAutoexposeHelper(AutoexposeHelper helper)Sets the current autoexpose helper.voidsetCurrentEvent(DropTargetEvent currentEvent)Sets the current DropTargetEvent.protected voidsetEnablementDeterminedByCommand(boolean value)Determines if the target editpart should be asked for a Command duringisEnabled(DropTargetEvent).protected voidsetTargetEditPart(EditPart ep)Sets the targetEditPart.protected voidsetTransfer(Transfer xfer)Sets the Tranfer type that this listener can handle.protected voidsetViewer(EditPartViewer viewer)Sets the EditPartViewer.protected voidshowTargetFeedback()Asks the targetEditPartto show target feedback if it is notnull.protected voidunload()Erases target feedback and sets the request tonull.protected voidupdateAutoexposeHelper()Updates the activeAutoexposeHelper.protected voidupdateTargetEditPart()Updates the target EditPart.protected abstract voidupdateTargetRequest()Subclasses must implement this to update the target Request.
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Constructor Detail
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AbstractTransferDropTargetListener
public AbstractTransferDropTargetListener(EditPartViewer viewer)
Constructs a new AbstractTransferDropTargetListener and sets the EditPartViewer. If you use this constructor, you must set the Transfer yourself usingsetTransfer(Transfer).- Parameters:
viewer- the EditPartViewer
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AbstractTransferDropTargetListener
public AbstractTransferDropTargetListener(EditPartViewer viewer, Transfer xfer)
Constructs a new AbstractTransferDropTargetListener and sets the EditPartViewer and Transfer. The Viewer's Control should be the Drop target.- Parameters:
viewer- the EditPartViewerxfer- the Transfer
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Method Detail
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createTargetRequest
protected Request createTargetRequest()
Creates and returns theRequestthat will be sent to the targeted EditPart. Subclasses can override to create specialized requests.- Returns:
- the
Requestto be used with the target EditPart
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dragEnter
public void dragEnter(DropTargetEvent event)
Stores the information about the current DropTargetEvent. This method may not be called on the listener, because the listener may not be made active until after the mouse has entered the drop target.- Specified by:
dragEnterin interfaceDropTargetListener- See Also:
DropTargetListener.dragEnter(DropTargetEvent)
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dragLeave
public void dragLeave(DropTargetEvent event)
Stores the information about the current DropTargetEvent and then callsunload(). Subclasses should overrideunload()to perform actions for this event. For some reason, SWT also callsdragLeave()when the actual drop is performed, even though the mouse has not left the drop target.- Specified by:
dragLeavein interfaceDropTargetListener- See Also:
DropTargetListener.dragLeave(DropTargetEvent)
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dragOperationChanged
public void dragOperationChanged(DropTargetEvent event)
Stores the information about the current DropTargetEvent and then callshandleDragOperationChanged(). Subclasses should overridehandleDragOperationChanged()to perform actions for this event.- Specified by:
dragOperationChangedin interfaceDropTargetListener- See Also:
DropTargetListener.dragOperationChanged(DropTargetEvent)
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dragOver
public void dragOver(DropTargetEvent event)
Stores the information about the current DropTargetEvent and then callshandleDragOver(). Subclasses should overridehandleDragOver()to perform actions for this event.- Specified by:
dragOverin interfaceDropTargetListener- See Also:
DropTargetListener.dragOver(org.eclipse.swt.dnd.DropTargetEvent)
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drop
public void drop(DropTargetEvent event)
Stores the information about the current DropTargetEvent and then callshandleDrop(), followed byunload(). Subclasses should override these methods to perform actions for this event.- Specified by:
dropin interfaceDropTargetListener- See Also:
DropTargetListener.drop(DropTargetEvent)
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dropAccept
public void dropAccept(DropTargetEvent event)
Stores the currentDropTargetEventand does nothing. By default, the drop is accepted.- Specified by:
dropAcceptin interfaceDropTargetListener- See Also:
DropTargetListener.dropAccept(DropTargetEvent)
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eraseTargetFeedback
protected void eraseTargetFeedback()
CallseraseTargetFeedback(Request)on the current target, using the target Request. Does nothing if there is no target, or if the target has not been requested to show target feedback.
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getCommand
protected Command getCommand()
Returns the current command from the target EditPart.- Returns:
- The current command from the target EditPart
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getCurrentEvent
public DropTargetEvent getCurrentEvent()
Returns the currentDropTargetEvent.- Returns:
- the current event
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getDropLocation
protected org.eclipse.draw2d.geometry.Point getDropLocation()
Returns the current mouse location, as aPoint. The location is relative to the control's client area.- Returns:
- the drop location
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getExclusionSet
protected java.util.Collection getExclusionSet()
Returns a Collection ofEditPartsthat are to be excluded when searching for the target EditPart.- Returns:
- A Collection of EditParts to be excluded
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getTargetEditPart
protected EditPart getTargetEditPart()
Returns the current targetEditPart.- Returns:
- the target EditPart
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getTargetRequest
protected Request getTargetRequest()
Returns the targetRequest. If the target Request isnull,createTargetRequest()is called and the newly created Request is returned.- Returns:
- the target Request
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getTransfer
public Transfer getTransfer()
- Specified by:
getTransferin interfaceTransferDropTargetListener- See Also:
TransferDropTargetListener.getTransfer()
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getViewer
protected EditPartViewer getViewer()
Returns theEditPartViewerthat is the target of the drop.- Returns:
- the EditPartViewer
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handleDragOperationChanged
protected void handleDragOperationChanged()
Called when the user changes the Drag operation. By default, target feedback is erased. The target Request and target EditPart are updated, and target feedback is re-displayed on the new target.
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handleDragOver
protected void handleDragOver()
Called whenever the User drags over the target. By default, the target Request and target EditPart are updated, feedback is shown, and auto-expose occurs.
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handleDrop
protected void handleDrop()
Updates the target Request and target EditPart, and performs the drop. By default, the drop is performed by asking the target EditPart for a Command using the target Request. This Command is then executed on the CommandStack.If there is no target EditPart or no executable Command, the event's
detailfield is set toDND.DROP_NONE.
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handleEnteredEditPart
protected void handleEnteredEditPart()
Called when a new target EditPart has been entered. By default, the new target is asked to show feedback.
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handleExitingEditPart
protected void handleExitingEditPart()
Called as the current target EditPart is being exited. By default, the target is asked to erase feedback.
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handleHover
protected void handleHover()
Called when the mouse hovers during drag and drop.
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handleHoverStop
protected void handleHoverStop()
Called when the mouse resumes motion after having hovered.
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isEnabled
public boolean isEnabled(DropTargetEvent event)
Returnstrueif this TransferDropTargetListener is enabled for the specifiedDropTargetEvent. By default, this is calculated by comparing the event'sdataTypeswith theTransfer'ssupported types (Transfer.isSupportedType(TransferData)). If a dataType is supported, an attempt is made to find a targetEditPartat the current drop location. If a targetEditPartis found,trueis returned, and the DropTargetEvent'sDropTargetEvent.currentDataTypeis set to the dataType that matched.- Specified by:
isEnabledin interfaceTransferDropTargetListener- Parameters:
event- the DropTargetEvent- Returns:
trueif this TransferDropTargetListener is enabled for the given DropTargetEvent
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isEnablementDeterminedByCommand
protected boolean isEnablementDeterminedByCommand()
ReturnstrueifisEnabled(DropTargetEvent)is determined by asking the potential target for a Command.- Returns:
trueif the target will be queried for aCommand- Since:
- 3.1
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setAutoexposeHelper
protected void setAutoexposeHelper(AutoexposeHelper helper)
Sets the current autoexpose helper.- Parameters:
helper- the autoexpose helper
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setEnablementDeterminedByCommand
protected void setEnablementDeterminedByCommand(boolean value)
Determines if the target editpart should be asked for a Command duringisEnabled(DropTargetEvent). For most DND operations, the data is not available, thus asking for a command would not make sense. The default value isfalse.- Parameters:
value-trueif a- Since:
- 3.1
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setCurrentEvent
public void setCurrentEvent(DropTargetEvent currentEvent)
Sets the current DropTargetEvent.- Parameters:
currentEvent- the DropTargetEvent
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setTargetEditPart
protected void setTargetEditPart(EditPart ep)
Sets the targetEditPart. If the target is changing,handleExitingEditPart()is called before the target changes, andhandleEnteredEditPart()is called afterwards.- Parameters:
ep- the new target EditPart
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setTransfer
protected void setTransfer(Transfer xfer)
Sets the Tranfer type that this listener can handle.- Parameters:
xfer- the Transfer
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setViewer
protected void setViewer(EditPartViewer viewer)
Sets the EditPartViewer.- Parameters:
viewer- the EditPartViewer
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showTargetFeedback
protected void showTargetFeedback()
Asks the targetEditPartto show target feedback if it is notnull.- See Also:
EditPart.showTargetFeedback(Request)
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unload
protected void unload()
Erases target feedback and sets the request tonull.
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updateAutoexposeHelper
protected void updateAutoexposeHelper()
Updates the activeAutoexposeHelper. Does nothing if there is still an active helper. Otherwise, obtains a new helper (possiblenull) at the current mouse location and callssetAutoexposeHelper(AutoexposeHelper).
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updateTargetEditPart
protected void updateTargetEditPart()
Updates the target EditPart.
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updateTargetRequest
protected abstract void updateTargetRequest()
Subclasses must implement this to update the target Request.
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