org.eclipse.gef.dnd
Class AbstractTransferDropTargetListener
java.lang.Object
org.eclipse.gef.dnd.AbstractTransferDropTargetListener
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All Implemented Interfaces:
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TransferDropTargetListener
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Direct Known Subclasses:
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TemplateTransferDropTargetListener
- public abstract class AbstractTransferDropTargetListener
- extends java.lang.Object
- implements
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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Methods inherited from class java.lang.Object
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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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 using
setTransfer(Transfer).
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Parameters:
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viewer - the EditPartViewer
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.
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Parameters:
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viewer - the EditPartViewer -
xfer - the Transfer
createTargetRequest
protected
Request createTargetRequest()
- Creates and returns the
Request that will be sent to the targeted
EditPart. Subclasses can override to create specialized requests.
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Returns:
- the
Request to be used with the target EditPart
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.
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See Also:
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DropTargetListener#dragEnter(DropTargetEvent)
dragLeave
public void dragLeave(DropTargetEvent event)
- Stores the information about the current DropTargetEvent and then calls
unload(). Subclasses should override
unload() to perform actions
for this event. For some reason, SWT also calls dragLeave() when the
actual drop is performed, even though the mouse has not left the drop target.
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See Also:
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DropTargetListener#dragLeave(DropTargetEvent)
dragOperationChanged
public void dragOperationChanged(DropTargetEvent event)
- Stores the information about the current DropTargetEvent and then calls
handleDragOperationChanged(). Subclasses should override
handleDragOperationChanged() to perform actions for this event.
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See Also:
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DropTargetListener#dragOperationChanged(DropTargetEvent)
dragOver
public void dragOver(DropTargetEvent event)
- Stores the information about the current DropTargetEvent and then calls
handleDragOver(). Subclasses should override
handleDragOver() to
perform actions for this event.
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See Also:
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DropTargetListener#dragOver(org.eclipse.swt.dnd.DropTargetEvent)
drop
public void drop(DropTargetEvent event)
- Stores the information about the current DropTargetEvent and then calls
handleDrop(), followed by
unload(). Subclasses should override
these methods to perform actions for this event.
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See Also:
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DropTargetListener#drop(DropTargetEvent)
dropAccept
public void dropAccept(DropTargetEvent event)
- Stores the current
DropTargetEvent and does nothing. By default, the drop
is accepted.
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See Also:
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DropTargetListener#dropAccept(DropTargetEvent)
eraseTargetFeedback
protected void eraseTargetFeedback()
- Calls
eraseTargetFeedback(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.
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Returns:
- The current command from the target EditPart
getCurrentEvent
public DropTargetEvent getCurrentEvent()
- Returns the current
DropTargetEvent.
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Returns:
- the current event
getDropLocation
protected
Point getDropLocation()
- Returns the current mouse location, as a
Point. The location is relative to the
control's client area.
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Returns:
- the drop location
getExclusionSet
protected java.util.Collection getExclusionSet()
- Returns a Collection of
EditParts that are to be excluded when
searching for the target EditPart.
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Returns:
- A Collection of EditParts to be excluded
getTargetEditPart
protected
EditPart getTargetEditPart()
- Returns the current target
EditPart.
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Returns:
- the target EditPart
getTargetRequest
protected
Request getTargetRequest()
- Returns the target
Request. If the target Request is null,
createTargetRequest() is called and the newly created Request is returned.
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Returns:
- the target Request
getTransfer
public Transfer getTransfer()
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See Also:
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TransferDropTargetListener#getTransfer()
getViewer
protected
EditPartViewer getViewer()
- Returns the
EditPartViewer that is the target of the drop.
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Returns:
- the EditPartViewer
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
detail field is set to DND.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)
- Returns
true if this TransferDropTargetListener is enabled for the
specified DropTargetEvent. By default, this is calculated by comparing
the event's dataTypes with the Transfer's
supported types (Transfer#isSupportedType(TransferData)). If a dataType is
supported, an attempt is made to find a target EditPart at the
current drop location. If a target EditPart is found, true is
returned, and the DropTargetEvent's DropTargetEvent#currentDataType is set to
the dataType that matched.
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Parameters:
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event - the DropTargetEvent
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Returns:
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true if this TransferDropTargetListener is enabled for the given
DropTargetEvent
isEnablementDeterminedByCommand
protected boolean isEnablementDeterminedByCommand()
- Returns
true if
isEnabled(DropTargetEvent) is
determined by asking the potential target for a Command.
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Returns:
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true if the target will be queried for a
Command
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Since:
- 3.1
setAutoexposeHelper
protected void setAutoexposeHelper(
AutoexposeHelper helper)
- Sets the current autoexpose helper.
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Parameters:
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helper - the autoexpose helper
setEnablementDeterminedByCommand
protected void setEnablementDeterminedByCommand(boolean value)
- Determines if the target editpart should be asked for a Command during
isEnabled(DropTargetEvent). For most DND operations, the data is not
available, thus asking for a command would not make sense. The default value
is false.
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Parameters:
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value - true if a -
Since:
- 3.1
setCurrentEvent
public void setCurrentEvent(DropTargetEvent currentEvent)
- Sets the current DropTargetEvent.
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Parameters:
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currentEvent - the DropTargetEvent
setTargetEditPart
protected void setTargetEditPart(
EditPart ep)
- Sets the target
EditPart. If the target is changing,
handleExitingEditPart() is called before the target changes, and
handleEnteredEditPart() is called afterwards.
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Parameters:
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ep - the new target EditPart
setTransfer
protected void setTransfer(Transfer xfer)
- Sets the Tranfer type that this listener can handle.
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Parameters:
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xfer - the Transfer
setViewer
protected void setViewer(
EditPartViewer viewer)
- Sets the EditPartViewer.
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Parameters:
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viewer - the EditPartViewer
showTargetFeedback
protected void showTargetFeedback()
- Asks the target
EditPart to show target feedback if it is not
null.
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See Also:
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EditPart.showTargetFeedback(Request)
unload
protected void unload()
- Erases target feedback and sets the request to
null.
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updateAutoexposeHelper
protected void updateAutoexposeHelper()
- Updates the active
AutoexposeHelper. Does nothing if there is still an active
helper. Otherwise, obtains a new helper (possible null) at the current
mouse location and calls
setAutoexposeHelper(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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Copyright (c) IBM Corp. and others 2000, 2007. All Rights Reserved.
