DropTarget (Java 2 Platform SE 5.0) (original) (raw)

java.awt.dnd

Class DropTarget

java.lang.Object java.awt.dnd.DropTarget

All Implemented Interfaces:

DropTargetListener, Serializable, EventListener

public class DropTarget

extends Object

implements DropTargetListener, Serializable

The DropTarget is associated with a Component when that Component wishes to accept drops during Drag and Drop operations.

EachDropTarget is associated with a FlavorMap. The default FlavorMap hereafter designates theFlavorMap returned by SystemFlavorMap.getDefaultFlavorMap().

Since:

1.2

See Also:

Serialized Form

DropTarget

public DropTarget(Component c, int ops, DropTargetListener dtl, boolean act, FlavorMap fm) throws HeadlessException

Creates a new DropTarget given the Component to associate itself with, an int representing the default acceptable action(s) to support, a DropTargetListener to handle event processing, a boolean indicating if the DropTarget is currently accepting drops, and a FlavorMap to use (or null for the default FlavorMap).

The Component will receive drops only if it is enabled.

Parameters:

c - The Component with which this DropTarget is associated

ops - The default acceptable actions for this DropTarget

dtl - The DropTargetListener for this DropTarget

act - Is the DropTarget accepting drops.

fm - The FlavorMap to use, or null for the default FlavorMap

Throws:

[HeadlessException](../../../java/awt/HeadlessException.html "class in java.awt") - if GraphicsEnvironment.isHeadless() returns true

See Also:

GraphicsEnvironment.isHeadless()

DropTarget

public DropTarget(Component c, int ops, DropTargetListener dtl, boolean act) throws HeadlessException

Creates a DropTarget given the Component to associate itself with, an int representing the default acceptable action(s) to support, a DropTargetListener to handle event processing, and a boolean indicating if the DropTarget is currently accepting drops.

The Component will receive drops only if it is enabled.

Parameters:

c - The Component with which this DropTarget is associated

ops - The default acceptable actions for this DropTarget

dtl - The DropTargetListener for this DropTarget

act - Is the DropTarget accepting drops.

Throws:

[HeadlessException](../../../java/awt/HeadlessException.html "class in java.awt") - if GraphicsEnvironment.isHeadless() returns true

See Also:

GraphicsEnvironment.isHeadless()

DropTarget

public DropTarget() throws HeadlessException

Creates a DropTarget.

Throws:

[HeadlessException](../../../java/awt/HeadlessException.html "class in java.awt") - if GraphicsEnvironment.isHeadless() returns true

See Also:

GraphicsEnvironment.isHeadless()

DropTarget

public DropTarget(Component c, DropTargetListener dtl) throws HeadlessException

Creates a DropTarget given the Component to associate itself with, and the DropTargetListener to handle event processing.

The Component will receive drops only if it is enabled.

Parameters:

c - The Component with which this DropTarget is associated

dtl - The DropTargetListener for this DropTarget

Throws:

[HeadlessException](../../../java/awt/HeadlessException.html "class in java.awt") - if GraphicsEnvironment.isHeadless() returns true

See Also:

GraphicsEnvironment.isHeadless()

DropTarget

public DropTarget(Component c, int ops, DropTargetListener dtl) throws HeadlessException

Creates a DropTarget given the Component to associate itself with, an int representing the default acceptable action(s) to support, and aDropTargetListener to handle event processing.

The Component will receive drops only if it is enabled.

Parameters:

c - The Component with which this DropTarget is associated

ops - The default acceptable actions for this DropTarget

dtl - The DropTargetListener for this DropTarget

Throws:

[HeadlessException](../../../java/awt/HeadlessException.html "class in java.awt") - if GraphicsEnvironment.isHeadless() returns true

See Also:

GraphicsEnvironment.isHeadless()

setComponent

public void setComponent(Component c)

Note: this interface is required to permit the safe association of a DropTarget with a Component in one of two ways, either:component.setDropTarget(droptarget); or droptarget.setComponent(component);

The Component will receive drops only if it is enabled.

Parameters:

c - The new Component this DropTarget is to be associated with.

getComponent

public Component getComponent()

Gets the Component associated with this DropTarget.

Returns:

the current Component

setDefaultActions

public void setDefaultActions(int ops)

Sets the default acceptable actions for this DropTarget

Parameters:

ops - the default actions

See Also:

DnDConstants

getDefaultActions

public int getDefaultActions()

Gets an int representing the current action(s) supported by this DropTarget.

Returns:

the current default actions

setActive

public void setActive(boolean isActive)

Sets the DropTarget active if true, inactive if false.

Parameters:

isActive - sets the DropTarget (in)active.

isActive

public boolean isActive()

Reports whether or not this DropTarget is currently active (ready to accept drops).

Returns:

true if active, false if not

addDropTargetListener

public void addDropTargetListener(DropTargetListener dtl) throws TooManyListenersException

Adds a new DropTargetListener (UNICAST SOURCE).

Parameters:

dtl - The new DropTargetListener

Throws:

`TooManyListenersException` - if a DropTargetListener is already added to thisDropTarget.

[TooManyListenersException](../../../java/util/TooManyListenersException.html "class in java.util")

removeDropTargetListener

public void removeDropTargetListener(DropTargetListener dtl)

Removes the current DropTargetListener (UNICAST SOURCE).

Parameters:

dtl - the DropTargetListener to deregister.

dragEnter

public void dragEnter(DropTargetDragEvent dtde)

Calls dragEnter on the registeredDropTargetListener and passes it the specified DropTargetDragEvent. Has no effect if this DropTarget is not active.

Specified by:

[dragEnter](../../../java/awt/dnd/DropTargetListener.html#dragEnter%28java.awt.dnd.DropTargetDragEvent%29) in interface [DropTargetListener](../../../java/awt/dnd/DropTargetListener.html "interface in java.awt.dnd")

Parameters:

dtde - the DropTargetDragEvent

Throws:

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if this DropTarget is active and dtde is null

See Also:

isActive()

dragOver

public void dragOver(DropTargetDragEvent dtde)

Calls dragOver on the registeredDropTargetListener and passes it the specified DropTargetDragEvent. Has no effect if this DropTarget is not active.

Specified by:

[dragOver](../../../java/awt/dnd/DropTargetListener.html#dragOver%28java.awt.dnd.DropTargetDragEvent%29) in interface [DropTargetListener](../../../java/awt/dnd/DropTargetListener.html "interface in java.awt.dnd")

Parameters:

dtde - the DropTargetDragEvent

Throws:

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if this DropTarget is active and dtde is null

See Also:

isActive()

dropActionChanged

public void dropActionChanged(DropTargetDragEvent dtde)

Calls dropActionChanged on the registeredDropTargetListener and passes it the specified DropTargetDragEvent. Has no effect if this DropTarget is not active.

Specified by:

[dropActionChanged](../../../java/awt/dnd/DropTargetListener.html#dropActionChanged%28java.awt.dnd.DropTargetDragEvent%29) in interface [DropTargetListener](../../../java/awt/dnd/DropTargetListener.html "interface in java.awt.dnd")

Parameters:

dtde - the DropTargetDragEvent

Throws:

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if this DropTarget is active and dtde is null

See Also:

isActive()

dragExit

public void dragExit(DropTargetEvent dte)

Calls dragExit on the registeredDropTargetListener and passes it the specified DropTargetEvent. Has no effect if this DropTarget is not active.

This method itself does not throw any exception for null parameter but for exceptions thrown by the respective method of the listener.

Specified by:

[dragExit](../../../java/awt/dnd/DropTargetListener.html#dragExit%28java.awt.dnd.DropTargetEvent%29) in interface [DropTargetListener](../../../java/awt/dnd/DropTargetListener.html "interface in java.awt.dnd")

Parameters:

dte - the DropTargetEvent

See Also:

isActive()

drop

public void drop(DropTargetDropEvent dtde)

Calls drop on the registeredDropTargetListener and passes it the specified DropTargetDropEvent if this DropTarget is active.

Specified by:

[drop](../../../java/awt/dnd/DropTargetListener.html#drop%28java.awt.dnd.DropTargetDropEvent%29) in interface [DropTargetListener](../../../java/awt/dnd/DropTargetListener.html "interface in java.awt.dnd")

Parameters:

dtde - the DropTargetDropEvent

Throws:

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if dtde is null and at least one of the following is true: thisDropTarget is not active, or there is no a DropTargetListener registered.

See Also:

isActive()

getFlavorMap

public FlavorMap getFlavorMap()

Gets the FlavorMap associated with this DropTarget. If no FlavorMap has been set for thisDropTarget, it is associated with the defaultFlavorMap.

Returns:

the FlavorMap for this DropTarget

setFlavorMap

public void setFlavorMap(FlavorMap fm)

Sets the FlavorMap associated with this DropTarget.

Parameters:

fm - the new FlavorMap, or null to associate the default FlavorMap with this DropTarget.

addNotify

public void addNotify(java.awt.peer.ComponentPeer peer)

Notify the DropTarget that it has been associated with a Component This method is usually called from java.awt.Component.addNotify() of the Component associated with this DropTarget to notify the DropTarget that a ComponentPeer has been associated with that Component. Calling this method, other than to notify this DropTarget of the association of the ComponentPeer with the Component may result in a malfunction of the DnD system.

Parameters:

peer - The Peer of the Component we are associated with!

removeNotify

public void removeNotify(java.awt.peer.ComponentPeer peer)

Notify the DropTarget that it has been disassociated from a Component This method is usually called from java.awt.Component.removeNotify() of the Component associated with this DropTarget to notify the DropTarget that a ComponentPeer has been disassociated with that Component. Calling this method, other than to notify this DropTarget of the disassociation of the ComponentPeer from the Component may result in a malfunction of the DnD system.

Parameters:

peer - The Peer of the Component we are being disassociated from!

getDropTargetContext

public DropTargetContext getDropTargetContext()

Gets the DropTargetContext associated with this DropTarget.

Returns:

the DropTargetContext associated with this DropTarget.

createDropTargetContext

protected DropTargetContext createDropTargetContext()

Creates the DropTargetContext associated with this DropTarget. Subclasses may override this method to instantiate their own DropTargetContext subclass. This call is typically *only* called by the platform's DropTargetContextPeer as a drag operation encounters this DropTarget. Accessing the Context while no Drag is current has undefined results.

createDropTargetAutoScroller

protected DropTarget.DropTargetAutoScroller createDropTargetAutoScroller(Component c, Point p)

create an embedded autoscroller

Parameters:

c - the Component

p - the Point

initializeAutoscrolling

protected void initializeAutoscrolling(Point p)

initialize autoscrolling

Parameters:

p - the Point

updateAutoscroll

protected void updateAutoscroll(Point dragCursorLocn)

update autoscrolling with current cursor locn

Parameters:

dragCursorLocn - the Point

clearAutoscroll

protected void clearAutoscroll()

clear autoscrolling

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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