ojluni/src/main/java/com/sun/java/swing/plaf/windows/DesktopProperty.java - platform/libcore - Git at Google

 /*
  * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 package com.sun.java.swing.plaf.windows;

 import java.awt.*;
 import java.beans.*;
 import java.lang.ref.*;
 import javax.swing.*;
 import javax.swing.plaf.*;

 /**
  * Wrapper for a value from the desktop. The value is lazily looked up, and
  * can be accessed using the <code>UIManager.ActiveValue</code> method
  * <code>createValue</code>. If the underlying desktop property changes this
  * will force the UIs to update all known Frames. You can invoke
  * <code>invalidate</code> to force the value to be fetched again.
  *
  */
 // NOTE: Don't rely on this class staying in this location. It is likely
 // to move to a different package in the future.
 public class DesktopProperty implements UIDefaults.ActiveValue {
     /**
      * Indicates if an updateUI call is pending.
      */
     private static boolean updatePending;

     /**
      * ReferenceQueue of unreferenced WeakPCLs.
      */
     private static final ReferenceQueue<DesktopProperty> queue = new ReferenceQueue<DesktopProperty>();

     /**
      * PropertyChangeListener attached to the Toolkit.
      */
     private WeakPCL pcl;
     /**
      * Key used to lookup value from desktop.
      */
     private final String key;
     /**
      * Value to return.
      */
     private Object value;
     /**
      * Fallback value in case we get null from desktop.
      */
     private final Object fallback;


     /**
      * Cleans up any lingering state held by unrefeernced
      * DesktopProperties.
      */
     static void flushUnreferencedProperties() {
         WeakPCL pcl;

         while ((pcl = (WeakPCL)queue.poll()) != null) {
             pcl.dispose();
         }
     }


     /**
      * Sets whether or not an updateUI call is pending.
      */
     private static synchronized void setUpdatePending(boolean update) {
         updatePending = update;
     }

     /**
      * Returns true if a UI update is pending.
      */
     private static synchronized boolean isUpdatePending() {
         return updatePending;
     }

     /**
      * Updates the UIs of all the known Frames.
      */
     private static void updateAllUIs() {
         // Check if the current UI is WindowsLookAndfeel and flush the XP style map.
         // Note: Change the package test if this class is moved to a different package.
         Class uiClass = UIManager.getLookAndFeel().getClass();
         if (uiClass.getPackage().equals(DesktopProperty.class.getPackage())) {
             XPStyle.invalidateStyle();
         }
         Frame appFrames[] = Frame.getFrames();
         for (Frame appFrame : appFrames) {
             updateWindowUI(appFrame);
         }
     }

     /**
      * Updates the UI of the passed in window and all its children.
      */
     private static void updateWindowUI(Window window) {
         SwingUtilities.updateComponentTreeUI(window);
         Window ownedWins[] = window.getOwnedWindows();
         for (Window ownedWin : ownedWins) {
             updateWindowUI(ownedWin);
         }
     }


     /**
      * Creates a DesktopProperty.
      *
      * @param key Key used in looking up desktop value.
      * @param fallback Value used if desktop property is null.
      */
     public DesktopProperty(String key, Object fallback) {
         this.key = key;
         this.fallback = fallback;
         // The only sure fire way to clear our references is to create a
         // Thread and wait for a reference to be added to the queue.
         // Because it is so rare that you will actually change the look
         // and feel, this stepped is forgoed and a middle ground of
         // flushing references from the constructor is instead done.
         // The implication is that once one DesktopProperty is created
         // there will most likely be n (number of DesktopProperties created
         // by the LookAndFeel) WeakPCLs around, but this number will not
         // grow past n.
         flushUnreferencedProperties();
     }

     /**
      * UIManager.LazyValue method, returns the value from the desktop
      * or the fallback value if the desktop value is null.
      */
     public Object createValue(UIDefaults table) {
         if (value == null) {
             value = configureValue(getValueFromDesktop());
             if (value == null) {
                 value = configureValue(getDefaultValue());
             }
         }
         return value;
     }

     /**
      * Returns the value from the desktop.
      */
     protected Object getValueFromDesktop() {
         Toolkit toolkit = Toolkit.getDefaultToolkit();

         if (pcl == null) {
             pcl = new WeakPCL(this, getKey(), UIManager.getLookAndFeel());
             toolkit.addPropertyChangeListener(getKey(), pcl);
         }

         return toolkit.getDesktopProperty(getKey());
     }

     /**
      * Returns the value to use if the desktop property is null.
      */
     protected Object getDefaultValue() {
         return fallback;
     }

     /**
      * Invalidates the current value.
      *
      * @param laf the LookAndFeel this DesktopProperty was created with
      */
     public void invalidate(LookAndFeel laf) {
         invalidate();
     }

     /**
      * Invalides the current value so that the next invocation of
      * <code>createValue</code> will ask for the property again.
      */
     public void invalidate() {
         value = null;
     }

     /**
      * Requests that all components in the GUI hierarchy be updated
      * to reflect dynamic changes in this look&feel.  This update occurs
      * by uninstalling and re-installing the UI objects. Requests are
      * batched and collapsed into a single update pass because often
      * many desktop properties will change at once.
      */
     protected void updateUI() {
         if (!isUpdatePending()) {
             setUpdatePending(true);
             Runnable uiUpdater = new Runnable() {
                 public void run() {
                     updateAllUIs();
                     setUpdatePending(false);
                 }
             };
             SwingUtilities.invokeLater(uiUpdater);
         }
     }

     /**
      * Configures the value as appropriate for a defaults property in
      * the UIDefaults table.
      */
     protected Object configureValue(Object value) {
         if (value != null) {
             if (value instanceof Color) {
                 return new ColorUIResource((Color)value);
             }
             else if (value instanceof Font) {
                 return new FontUIResource((Font)value);
             }
             else if (value instanceof UIDefaults.LazyValue) {
                 value = ((UIDefaults.LazyValue)value).createValue(null);
             }
             else if (value instanceof UIDefaults.ActiveValue) {
                 value = ((UIDefaults.ActiveValue)value).createValue(null);
             }
         }
         return value;
     }

     /**
      * Returns the key used to lookup the desktop properties value.
      */
     protected String getKey() {
         return key;
     }


     /**
      * As there is typically only one Toolkit, the PropertyChangeListener
      * is handled via a WeakReference so as not to pin down the
      * DesktopProperty.
      */
     private static class WeakPCL extends WeakReference<DesktopProperty>
                                implements PropertyChangeListener {
         private String key;
         private LookAndFeel laf;

         WeakPCL(DesktopProperty target, String key, LookAndFeel laf) {
             super(target, queue);
             this.key = key;
             this.laf = laf;
         }

         public void propertyChange(PropertyChangeEvent pce) {
             DesktopProperty property = get();

             if (property == null || laf != UIManager.getLookAndFeel()) {
                 // The property was GC'ed, we're no longer interested in
                 // PropertyChanges, remove the listener.
                 dispose();
             }
             else {
                 property.invalidate(laf);
                 property.updateUI();
             }
         }

         void dispose() {
             Toolkit.getDefaultToolkit().removePropertyChangeListener(key, this);
         }
     }
 }
	/*
	* Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/
	package com.sun.java.swing.plaf.windows;

	import java.awt.*;
	import java.beans.*;
	import java.lang.ref.*;
	import javax.swing.*;
	import javax.swing.plaf.*;

	/**
	* Wrapper for a value from the desktop. The value is lazily looked up, and
	* can be accessed using the <code>UIManager.ActiveValue</code> method
	* <code>createValue</code>. If the underlying desktop property changes this
	* will force the UIs to update all known Frames. You can invoke
	* <code>invalidate</code> to force the value to be fetched again.
	*
	*/
	// NOTE: Don't rely on this class staying in this location. It is likely
	// to move to a different package in the future.
	public class DesktopProperty implements UIDefaults.ActiveValue {
	/**
	* Indicates if an updateUI call is pending.
	*/
	private static boolean updatePending;

	/**
	* ReferenceQueue of unreferenced WeakPCLs.
	*/
	private static final ReferenceQueue<DesktopProperty> queue = new ReferenceQueue<DesktopProperty>();

	/**
	* PropertyChangeListener attached to the Toolkit.
	*/
	private WeakPCL pcl;
	/**
	* Key used to lookup value from desktop.
	*/
	private final String key;
	/**
	* Value to return.
	*/
	private Object value;
	/**
	* Fallback value in case we get null from desktop.
	*/
	private final Object fallback;


	/**
	* Cleans up any lingering state held by unrefeernced
	* DesktopProperties.
	*/
	static void flushUnreferencedProperties() {
	WeakPCL pcl;

	while ((pcl = (WeakPCL)queue.poll()) != null) {
	pcl.dispose();
	}
	}


	/**
	* Sets whether or not an updateUI call is pending.
	*/
	private static synchronized void setUpdatePending(boolean update) {
	updatePending = update;
	}

	/**
	* Returns true if a UI update is pending.
	*/
	private static synchronized boolean isUpdatePending() {
	return updatePending;
	}

	/**
	* Updates the UIs of all the known Frames.
	*/
	private static void updateAllUIs() {
	// Check if the current UI is WindowsLookAndfeel and flush the XP style map.
	// Note: Change the package test if this class is moved to a different package.
	Class uiClass = UIManager.getLookAndFeel().getClass();
	if (uiClass.getPackage().equals(DesktopProperty.class.getPackage())) {
	XPStyle.invalidateStyle();
	}
	Frame appFrames[] = Frame.getFrames();
	for (Frame appFrame : appFrames) {
	updateWindowUI(appFrame);
	}
	}

	/**
	* Updates the UI of the passed in window and all its children.
	*/
	private static void updateWindowUI(Window window) {
	SwingUtilities.updateComponentTreeUI(window);
	Window ownedWins[] = window.getOwnedWindows();
	for (Window ownedWin : ownedWins) {
	updateWindowUI(ownedWin);
	}
	}


	/**
	* Creates a DesktopProperty.
	*
	* @param key Key used in looking up desktop value.
	* @param fallback Value used if desktop property is null.
	*/
	public DesktopProperty(String key, Object fallback) {
	this.key = key;
	this.fallback = fallback;
	// The only sure fire way to clear our references is to create a
	// Thread and wait for a reference to be added to the queue.
	// Because it is so rare that you will actually change the look
	// and feel, this stepped is forgoed and a middle ground of
	// flushing references from the constructor is instead done.
	// The implication is that once one DesktopProperty is created
	// there will most likely be n (number of DesktopProperties created
	// by the LookAndFeel) WeakPCLs around, but this number will not
	// grow past n.
	flushUnreferencedProperties();
	}

	/**
	* UIManager.LazyValue method, returns the value from the desktop
	* or the fallback value if the desktop value is null.
	*/
	public Object createValue(UIDefaults table) {
	if (value == null) {
	value = configureValue(getValueFromDesktop());
	if (value == null) {
	value = configureValue(getDefaultValue());
	}
	}
	return value;
	}

	/**
	* Returns the value from the desktop.
	*/
	protected Object getValueFromDesktop() {
	Toolkit toolkit = Toolkit.getDefaultToolkit();

	if (pcl == null) {
	pcl = new WeakPCL(this, getKey(), UIManager.getLookAndFeel());
	toolkit.addPropertyChangeListener(getKey(), pcl);
	}

	return toolkit.getDesktopProperty(getKey());
	}

	/**
	* Returns the value to use if the desktop property is null.
	*/
	protected Object getDefaultValue() {
	return fallback;
	}

	/**
	* Invalidates the current value.
	*
	* @param laf the LookAndFeel this DesktopProperty was created with
	*/
	public void invalidate(LookAndFeel laf) {
	invalidate();
	}

	/**
	* Invalides the current value so that the next invocation of
	* <code>createValue</code> will ask for the property again.
	*/
	public void invalidate() {
	value = null;
	}

	/**
	* Requests that all components in the GUI hierarchy be updated
	* to reflect dynamic changes in this look&feel. This update occurs
	* by uninstalling and re-installing the UI objects. Requests are
	* batched and collapsed into a single update pass because often
	* many desktop properties will change at once.
	*/
	protected void updateUI() {
	if (!isUpdatePending()) {
	setUpdatePending(true);
	Runnable uiUpdater = new Runnable() {
	public void run() {
	updateAllUIs();
	setUpdatePending(false);
	}
	};
	SwingUtilities.invokeLater(uiUpdater);
	}
	}

	/**
	* Configures the value as appropriate for a defaults property in
	* the UIDefaults table.
	*/
	protected Object configureValue(Object value) {
	if (value != null) {
	if (value instanceof Color) {
	return new ColorUIResource((Color)value);
	}
	else if (value instanceof Font) {
	return new FontUIResource((Font)value);
	}
	else if (value instanceof UIDefaults.LazyValue) {
	value = ((UIDefaults.LazyValue)value).createValue(null);
	}
	else if (value instanceof UIDefaults.ActiveValue) {
	value = ((UIDefaults.ActiveValue)value).createValue(null);
	}
	}
	return value;
	}

	/**
	* Returns the key used to lookup the desktop properties value.
	*/
	protected String getKey() {
	return key;
	}



	/**
	* As there is typically only one Toolkit, the PropertyChangeListener
	* is handled via a WeakReference so as not to pin down the
	* DesktopProperty.
	*/
	private static class WeakPCL extends WeakReference<DesktopProperty>
	implements PropertyChangeListener {
	private String key;
	private LookAndFeel laf;

	WeakPCL(DesktopProperty target, String key, LookAndFeel laf) {
	super(target, queue);
	this.key = key;
	this.laf = laf;
	}

	public void propertyChange(PropertyChangeEvent pce) {
	DesktopProperty property = get();

	if (property == null \|\| laf != UIManager.getLookAndFeel()) {
	// The property was GC'ed, we're no longer interested in
	// PropertyChanges, remove the listener.
	dispose();
	}
	else {
	property.invalidate(laf);
	property.updateUI();
	}
	}

	void dispose() {
	Toolkit.getDefaultToolkit().removePropertyChangeListener(key, this);
	}
	}
	}