Package org.eclipse.gef.dnd
Class AbstractTransferDropTargetListener
java.lang.Object
org.eclipse.gef.dnd.AbstractTransferDropTargetListener
- All Implemented Interfaces:
EventListener,TransferDropTargetListener,TransferDropTargetListener,DropTargetListener
- Direct Known Subclasses:
TemplateTransferDropTargetListener
public abstract class AbstractTransferDropTargetListener
extends Object
implements TransferDropTargetListener, TransferDropTargetListener
An abstract implementation of TransferDropTargetListener for use with
EditPartViewers. The Viewer's Control should be the Drop
target. In order to communicate with EditParts in a consistent way,
DropTargetEvents are processed into Requests.
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
ConstructorsConstructorDescriptionConstructs a new AbstractTransferDropTargetListener and sets the EditPartViewer.AbstractTransferDropTargetListener(EditPartViewer viewer, Transfer xfer) Constructs a new AbstractTransferDropTargetListener and sets the EditPartViewer and Transfer. -
Method Summary
Modifier and TypeMethodDescriptionprotected RequestCreates 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().voidStores 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 voidCallseraseTargetFeedback(Request)on the current target, using the target Request.protected CommandReturns the current command from the target EditPart.Returns the currentDropTargetEvent.protected PointReturns the current mouse location, as aPoint.protected Collection<EditPart> Returns a Collection ofEditPartsthat are to be excluded when searching for the target EditPart.protected EditPartReturns the current targetEditPart.protected RequestReturns the targetRequest.protected EditPartViewerReturns theEditPartViewerthat is the target of the drop.protected voidCalled when the user changes the Drag operation.protected voidCalled whenever the User drags over the target.protected voidUpdates the target Request and target EditPart, and performs the drop.protected voidCalled when a new target EditPart has been entered.protected voidCalled as the current target EditPart is being exited.protected voidCalled when the mouse hovers during drag and drop.protected voidCalled when the mouse resumes motion after having hovered.booleanisEnabled(DropTargetEvent event) Returnstrueif this TransferDropTargetListener is enabled for the specifiedDropTargetEvent.protected booleanReturnstrueifisEnabled(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 voidSets the targetEditPart.protected voidsetTransfer(Transfer xfer) Sets the Tranfer type that this listener can handle.protected voidsetViewer(EditPartViewer viewer) Sets the EditPartViewer.protected voidAsks the targetEditPartto show target feedback if it is notnull.protected voidunload()Erases target feedback and sets the request tonull.protected voidUpdates the activeAutoexposeHelper.protected voidUpdates the target EditPart.protected abstract voidSubclasses must implement this to update the target Request.
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Constructor Details
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AbstractTransferDropTargetListener
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
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 Details
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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
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:
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dragLeave
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:
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dragOperationChanged
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:
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dragOver
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:
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drop
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:
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dropAccept
Stores the currentDropTargetEventand does nothing. By default, the drop is accepted.- Specified by:
dropAcceptin interfaceDropTargetListener- See Also:
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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. -
getCommand
Returns the current command from the target EditPart.- Returns:
- The current command from the target EditPart
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getCurrentEvent
Returns the currentDropTargetEvent.- Returns:
- the current event
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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
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
Returns the current targetEditPart.- Returns:
- the target EditPart
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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
- Specified by:
getTransferin interfaceTransferDropTargetListener- See Also:
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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. -
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. -
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. -
handleEnteredEditPart
protected void handleEnteredEditPart()Called when a new target EditPart has been entered. By default, the new target is asked to show feedback. -
handleExitingEditPart
protected void handleExitingEditPart()Called as the current target EditPart is being exited. By default, the target is asked to erase feedback. -
handleHover
protected void handleHover()Called when the mouse hovers during drag and drop. -
handleHoverStop
protected void handleHoverStop()Called when the mouse resumes motion after having hovered. -
isEnabled
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
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
Sets the current DropTargetEvent.- Parameters:
currentEvent- the DropTargetEvent
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setTargetEditPart
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
Sets the Tranfer type that this listener can handle.- Parameters:
xfer- the Transfer
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setViewer
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:
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unload
protected void unload()Erases target feedback and sets the request tonull. -
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). -
updateTargetEditPart
protected void updateTargetEditPart()Updates the target EditPart. -
updateTargetRequest
protected abstract void updateTargetRequest()Subclasses must implement this to update the target Request.
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