org.jhotdraw.draw.action
Class AbstractDrawingViewAction

java.lang.Object
  javax.swing.AbstractAction
      org.jhotdraw.draw.action.AbstractDrawingViewAction

All Implemented Interfaces:

java.awt.event.ActionListener, java.io.Serializable, java.lang.Cloneable, java.util.EventListener, javax.swing.Action, Disposable

Direct Known Subclasses:

DrawingAttributeAction, EditCanvasAction, EditGridAction, ToggleGridAction, ZoomAction

public abstract class AbstractDrawingViewAction
extends javax.swing.AbstractAction
implements Disposable

This abstract class can be extended to implement an Action that acts on behalf of a DrawingView.

By default the enabled state of this action reflects the enabled state of the DrawingView. If no drawing view is active, this action is disabled. When many actions listen to the enabled state this can considerably slow down the editor. If updating the enabled state is not necessary, you can disable it using setUpdateEnabledState(boolean).

If the AbstractDrawingEditorAction acts on the currently active DrawingView it listens for property changes in the DrawingEditor. It listens using a WeakPropertyChangeListener on the DrawingEditor and thus may become garbage collected if it is not referenced by any other object.

Version:

$Id: AbstractDrawingViewAction.java 527 2009-06-07 14:28:19Z rawcoder $

Author:

Werner Randelshofer

See Also:

Serialized Form

Nested Class Summary

private class

AbstractDrawingViewAction.EventHandler

Field Summary

private DrawingView	activeView
private DrawingEditor	editor
private AbstractDrawingViewAction.EventHandler	eventHandler
private DrawingView	specificView

Fields inherited from class javax.swing.AbstractAction

changeSupport, enabled

Fields inherited from interface javax.swing.Action

ACCELERATOR_KEY, ACTION_COMMAND_KEY, DEFAULT, DISPLAYED_MNEMONIC_INDEX_KEY, LARGE_ICON_KEY, LONG_DESCRIPTION, MNEMONIC_KEY, NAME, SELECTED_KEY, SHORT_DESCRIPTION, SMALL_ICON

Constructor Summary

AbstractDrawingViewAction(DrawingEditor editor)
Creates a view action which acts on the current view of the editor.

AbstractDrawingViewAction(DrawingView view)
Creates a view action which acts on the specified view.

Method Summary

void	dispose() Frees all resources held by this object, so that it can be garbage collected.
protected void	fireUndoableEditHappened(javax.swing.undo.UndoableEdit edit)
protected Drawing	getDrawing()
protected DrawingEditor	getEditor()
protected DrawingView	getView()
boolean	isUpdatEnabledState() Returns true, if this action automatically updates its enabled state to reflect the enabled state of the active DrawingView.
private void	registerEventHandler() Registers the event handler from the drawing editor and the active drawing view.
protected void	setEditor(DrawingEditor newValue)
void	setUpdateEnabledState(boolean newValue) By default, the enabled state of this action is updated to reflect the enabled state of the active DrawingView.
private void	unregisterEventHandler() Unregisters the event handler from the drawing editor and the active drawing view.
void	updateEnabledState() Updates the enabled state of this action to reflect the enabled state of the active DrawingView.
protected void	updateViewState() This method is called when the active drawing view of the drawing editor changed.

Methods inherited from class javax.swing.AbstractAction

addPropertyChangeListener, clone, firePropertyChange, getKeys, getPropertyChangeListeners, getValue, isEnabled, putValue, removePropertyChangeListener, setEnabled

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.awt.event.ActionListener

actionPerformed

Field Detail

editor

private DrawingEditor editor

specificView

private DrawingView specificView

activeView

private transient DrawingView activeView

eventHandler

private AbstractDrawingViewAction.EventHandler eventHandler

Constructor Detail

AbstractDrawingViewAction

public AbstractDrawingViewAction(DrawingEditor editor)

Creates a view action which acts on the current view of the editor.

AbstractDrawingViewAction

public AbstractDrawingViewAction(DrawingView view)

Creates a view action which acts on the specified view.

Method Detail

setEditor

protected void setEditor(DrawingEditor newValue)

getEditor

protected DrawingEditor getEditor()

getView

protected DrawingView getView()

getDrawing

protected Drawing getDrawing()

fireUndoableEditHappened

protected void fireUndoableEditHappened(javax.swing.undo.UndoableEdit edit)

updateEnabledState

public void updateEnabledState()

Updates the enabled state of this action to reflect the enabled state of the active DrawingView. If no drawing view is active, this action is disabled.

updateViewState

protected void updateViewState()

This method is called when the active drawing view of the drawing editor changed. The implementation in this class does nothing.

dispose

public void dispose()

Frees all resources held by this object, so that it can be garbage collected.

Specified by:

dispose in interface Disposable

setUpdateEnabledState

public void setUpdateEnabledState(boolean newValue)

By default, the enabled state of this action is updated to reflect the enabled state of the active DrawingView. Since this is not always necessary, and since many listening actions may considerably slow down the drawing editor, you can switch this behavior off here.

Parameters:

newValue - Specify false to prevent automatic updating of the enabled state.

isUpdatEnabledState

public boolean isUpdatEnabledState()

Returns true, if this action automatically updates its enabled state to reflect the enabled state of the active DrawingView.

unregisterEventHandler

private void unregisterEventHandler()

Unregisters the event handler from the drawing editor and the active drawing view.

registerEventHandler

private void registerEventHandler()

Registers the event handler from the drawing editor and the active drawing view.