[cp-patches] Proposed: javax.swing.UIManager patch

[David Gilbert]

This patch does two things primarily:

(1) corrects a problem where every call to "get" a default value ends up calling the 
getDefaults() method in the current LookAndFeel, which *creates* a new table of 
defaults each time it is called (the API docs say it should only be called once - a 
better name for the method would be createDefaults()).  The solution is to retain a 
reference to the UIDefaults for the current look and feel, and use that reference in 
getLookAndFeelDefaults() (and change all the get methods to use 
getLookAndFeelDefaults());

(2) implements the property change mechanism in UIManager using the 
SwingPropertyChangeSupport class.

I've also added API doc comments.  If the patch is too messy, I'll take some more 
time to split it into the relevant pieces.

Or is it OK to commit as is?

Regards,

Dave Gilbert

Index: javax/swing/UIManager.java
===================================================================
RCS file: /cvsroot/classpath/classpath/javax/swing/UIManager.java,v
retrieving revision 1.22
diff -u -r1.22 UIManager.java
--- javax/swing/UIManager.java  22 Aug 2005 13:28:44 -0000      1.22
+++ javax/swing/UIManager.java  23 Aug 2005 11:55:18 -0000
@@ -47,15 +47,31 @@
 import java.util.Locale;
 
 import javax.swing.border.Border;
+import javax.swing.event.SwingPropertyChangeSupport;
 import javax.swing.plaf.ComponentUI;
 import javax.swing.plaf.metal.MetalLookAndFeel;
 
+/**
+ * Manages the current address@hidden LookAndFeel} and any auxiliary 
address@hidden LookAndFeel}
+ * instances.
+ */
 public class UIManager implements Serializable
 {
+  /**
+   * Represents the basic information about a address@hidden LookAndFeel} 
(LAF), so 
+   * that a list of installed LAFs can be presented without actually loading 
+   * the LAF class(es).
+   */
   public static class LookAndFeelInfo
   {
     String name, clazz;
        
+    /**
+     * Creates a new instance.
+     * 
+     * @param name  the look and feel name.
+     * @param clazz  the look and feel class name.
+     */
     public LookAndFeelInfo(String name, 
                           String clazz)
     {
@@ -63,11 +79,21 @@
       this.clazz = clazz;
     }
 
+    /**
+     * Returns the name of the look and feel.
+     * 
+     * @return The name of the look and feel.
+     */
     public String getName()
     {
       return name;
     }
     
+    /**
+     * Returns the fully qualified class name for the address@hidden 
LookAndFeel}.
+     * 
+     * @return The fully qualified class name for the address@hidden 
LookAndFeel}.
+     */
     public String getClassName()
     {
       return clazz;
@@ -93,13 +119,22 @@
 
   private static final long serialVersionUID = -5547433830339189365L;
 
+  /** The installed look and feel(s). */
   static LookAndFeelInfo [] installed = {
-    new LookAndFeelInfo ("Metal", "javax.swing.plaf.metal.MetalLookAndFeel")
+    new LookAndFeelInfo("Metal", "javax.swing.plaf.metal.MetalLookAndFeel")
   };
 
-  static LookAndFeel[] aux_installed;
+  /** The installed auxiliary look and feels. */
+  static LookAndFeel[] auxLookAndFeels;
+  
+  /** The current look and feel. */
+  static LookAndFeel currentLookAndFeel;
   
-  static LookAndFeel look_and_feel = new MetalLookAndFeel();
+  static UIDefaults currentUIDefaults;
+
+  /** Property change listener mechanism. */
+  static SwingPropertyChangeSupport listeners 
+      = new SwingPropertyChangeSupport(UIManager.class);
 
   static
   {
@@ -115,11 +150,20 @@
     catch (Exception ex)
       {
         System.err.println("cannot initialize Look and Feel: " + defaultlaf);
+        ex.printStackTrace();
         System.err.println("error: " + ex.getMessage());
         System.err.println("falling back to Metal Look and Feel");
       }
-  }
+    currentLookAndFeel = new MetalLookAndFeel();
+    currentLookAndFeel.initialize();
+    currentUIDefaults = currentLookAndFeel.getDefaults();
 
+  }
+  
+  /**
+   * Creates a new instance of the <code>UIManager</code>.  There is no need
+   * to construct an instance of this class, since all methods are static.
+   */
   public UIManager()
   {
     // Do nothing here.
@@ -132,7 +176,7 @@
    */
   public static void addPropertyChangeListener(PropertyChangeListener listener)
   {
-    // FIXME
+    listeners.addPropertyChangeListener(listener);
   }
 
   /**
@@ -140,9 +184,10 @@
    *
    * @param listener the listener to remove
    */
-  public static void removePropertyChangeListener(PropertyChangeListener 
listener)
+  public static void removePropertyChangeListener(PropertyChangeListener 
+          listener)
   {
-    // FIXME
+    listeners.removePropertyChangeListener(listener);
   }
 
   /**
@@ -154,60 +199,117 @@
    */
   public static PropertyChangeListener[] getPropertyChangeListeners()
   {
-    // FIXME
-    throw new Error ("Not implemented");
+    return listeners.getPropertyChangeListeners();
   }
 
   /**
-   * Add a LookAndFeel to the list of auxiliary look and feels.
+   * Add a address@hidden LookAndFeel} to the list of auxiliary look and feels.
+   * 
+   * @param laf  the auxiliary look and feel (<code>null</code> not permitted).
+   * 
+   * @throws NullPointerException if <code>laf</code> is <code>null</code>.
+   * 
+   * @see #getAuxiliaryLookAndFeels()
    */
-  public static void addAuxiliaryLookAndFeel (LookAndFeel l)
+  public static void addAuxiliaryLookAndFeel(LookAndFeel laf)
   {
-    if (aux_installed == null)
+    if (laf == null)
+      throw new NullPointerException("Null 'laf' argument.");
+    if (auxLookAndFeels == null)
       {
-        aux_installed = new LookAndFeel[1];
-        aux_installed[0] = l;
+        auxLookAndFeels = new LookAndFeel[1];
+        auxLookAndFeels[0] = laf;
         return;
       }
        
-    LookAndFeel[] T = new LookAndFeel[ aux_installed.length+1 ];
-    System.arraycopy(aux_installed, 0, T, 0, aux_installed.length);            
         
-    aux_installed = T;
-    aux_installed[aux_installed.length-1] = l;
+    LookAndFeel[] temp = new LookAndFeel[auxLookAndFeels.length + 1];
+    System.arraycopy(auxLookAndFeels, 0, temp, 0, auxLookAndFeels.length);     
                 
+    auxLookAndFeels = temp;
+    auxLookAndFeels[auxLookAndFeels.length - 1] = laf;
   }
     
+  /**
+   * Removes a address@hidden LookAndFeel} (LAF) from the list of auxiliary 
LAFs.
+   * 
+   * @param laf  the LAF to remove.
+   * 
+   * @return <code>true</code> if the LAF was removed, and <code>false</code>
+   *         otherwise.
+   */
   public static boolean removeAuxiliaryLookAndFeel(LookAndFeel laf)
   {
-    if (aux_installed == null)
+    if (auxLookAndFeels == null)
       return false;
-
-    for (int i=0;i<aux_installed.length;i++)
+    int count = auxLookAndFeels.length;
+    if (count == 1 && auxLookAndFeels[0] == laf)
       {
-        if (aux_installed[i] == laf)
+        auxLookAndFeels = null;
+        return true;
+      }
+    for (int i = 0; i < count; i++)
+      {
+        if (auxLookAndFeels[i] == laf)
           {
-            aux_installed[ i ] = aux_installed[aux_installed.length-1];
-            LookAndFeel[] T = new LookAndFeel[ aux_installed.length-1 ];
-            System.arraycopy (aux_installed, 0, T, 0, aux_installed.length-1);
-            aux_installed = T;
+            LookAndFeel[] temp = new LookAndFeel[auxLookAndFeels.length - 1];
+            if (i == 0)
+              {
+                System.arraycopy(auxLookAndFeels, 1, temp, 0, count - 1);  
+              }
+            else if (i == count - 1)
+              {
+                System.arraycopy(auxLookAndFeels, 0, temp, 0, count - 1);
+              }
+            else 
+              {
+                System.arraycopy(auxLookAndFeels, 0, temp, 0, i);
+                System.arraycopy(auxLookAndFeels, i + 1, temp, i, 
+                        count - i - 1);
+              }
+            auxLookAndFeels = temp;
             return true;
           }            
       }
     return false;
   }
 
-  public static  LookAndFeel[] getAuxiliaryLookAndFeels()
+  /**
+   * Returns an array (possibly <code>null</code>) containing the auxiliary
+   * address@hidden LookAndFeel}s that are in use.  These are used by the 
+   * address@hidden javax.swing.plaf.multi.MultiLookAndFeel} class.
+   * 
+   * @return The auxiliary look and feels (possibly <code>null</code>).
+   * 
+   * @see #addAuxiliaryLookAndFeel(LookAndFeel)
+   */
+  public static LookAndFeel[] getAuxiliaryLookAndFeels()
   {
-    return aux_installed;
+    return auxLookAndFeels;
   }
 
-  public static  Object get(Object key)
+  /**
+   * Returns an object from the address@hidden UIDefaults} table for the 
current
+   * address@hidden LookAndFeel}.
+   * 
+   * @param key  the key.
+   * 
+   * @return The object.
+   */
+  public static Object get(Object key)
   {
-    return getLookAndFeel().getDefaults().get(key);
+    return getLookAndFeelDefaults().get(key);
   }
 
-  public static  Object get(Object key, Locale locale)
+  /**
+   * Returns an object from the address@hidden UIDefaults} table for the 
current
+   * address@hidden LookAndFeel}.
+   * 
+   * @param key  the key.
+   * 
+   * @return The object.
+   */
+  public static Object get(Object key, Locale locale)
   {
-    return getLookAndFeel().getDefaults().get(key ,locale);
+    return getLookAndFeelDefaults().get(key ,locale);
   }
 
   /**
@@ -218,7 +320,7 @@
    */
   public static boolean getBoolean(Object key)
   {
-    Boolean value = (Boolean) getLookAndFeel().getDefaults().get(key);
+    Boolean value = (Boolean) getLookAndFeelDefaults().get(key);
     return value != null ? value.booleanValue() : false;
   }
   
@@ -230,7 +332,7 @@
    */
   public static boolean getBoolean(Object key, Locale locale)
   {
-    Boolean value = (Boolean) getLookAndFeel().getDefaults().get(key, locale);
+    Boolean value = (Boolean) getLookAndFeelDefaults().get(key, locale);
     return value != null ? value.booleanValue() : false;
   }
     
@@ -239,7 +341,7 @@
    */
   public static Border getBorder(Object key)
   {
-    return (Border) getLookAndFeel().getDefaults().get(key);
+    return (Border) getLookAndFeelDefaults().get(key);
   }
     
   /**
@@ -249,39 +351,44 @@
    */
   public static Border getBorder(Object key, Locale locale)
   {
-    return (Border) getLookAndFeel().getDefaults().get(key, locale);
+    return (Border) getLookAndFeelDefaults().get(key, locale);
   }
     
   /**
    * Returns a drawing color from the defaults table. 
    */
-  public static  Color getColor(Object key)
+  public static Color getColor(Object key)
   {
-    return (Color) getLookAndFeel().getDefaults().get(key);
+    return (Color) getLookAndFeelDefaults().get(key);
   }
 
   /**
    * Returns a drawing color from the defaults table. 
    */
-  public static  Color getColor(Object key, Locale locale)
+  public static Color getColor(Object key, Locale locale)
   {
-    return (Color) getLookAndFeel().getDefaults().get(key);
+    return (Color) getLookAndFeelDefaults().get(key);
   }
 
   /**
-   * this string can be passed to Class.forName()
+   * The fully qualified class name of the cross platform (Metal) look and 
feel.
+   * This string can be passed to Class.forName()
+   * 
+   * @return <code>"javax.swing.plaf.metal.MetalLookAndFeel"</code>
    */
-  public static  String getCrossPlatformLookAndFeelClassName()
+  public static String getCrossPlatformLookAndFeelClassName()
   {    
     return "javax.swing.plaf.metal.MetalLookAndFeel";
   }
 
   /**
    * Returns the default values for this look and feel. 
+   * 
+   * @return The address@hidden UIDefaults} for the current address@hidden 
LookAndFeel}.
    */
   public static UIDefaults getDefaults()
   {
-    return getLookAndFeel().getDefaults();
+    return currentUIDefaults;
   }
 
   /**
@@ -289,7 +396,7 @@
    */
   public static Dimension getDimension(Object key)
   {
-    return (Dimension) getLookAndFeel().getDefaults().get(key);
+    return (Dimension) getLookAndFeelDefaults().get(key);
   }
 
   /**
@@ -297,7 +404,7 @@
    */
   public static Dimension getDimension(Object key, Locale locale)
   {
-    return (Dimension) getLookAndFeel().getDefaults().get(key, locale);
+    return (Dimension) getLookAndFeelDefaults().get(key, locale);
   }
 
   /**
@@ -310,7 +417,7 @@
    */
   public static Font getFont(Object key)
   {
-    return (Font) getLookAndFeel().getDefaults().get(key);
+    return (Font) getLookAndFeelDefaults().get(key);
   }
 
   /**
@@ -323,7 +430,7 @@
    */
   public static Font getFont(Object key, Locale locale)
   {
-    return (Font) getLookAndFeel().getDefaults().get(key ,locale);
+    return (Font) getLookAndFeelDefaults().get(key ,locale);
   }
 
   /**
@@ -331,7 +438,7 @@
    */
   public static Icon getIcon(Object key)
   {
-    return (Icon) getLookAndFeel().getDefaults().get(key);
+    return (Icon) getLookAndFeelDefaults().get(key);
   }
   
   /**
@@ -339,7 +446,7 @@
    */
   public static Icon getIcon(Object key, Locale locale)
   {
-    return (Icon) getLookAndFeel().getDefaults().get(key, locale);
+    return (Icon) getLookAndFeelDefaults().get(key, locale);
   }
   
   /**
@@ -347,7 +454,7 @@
    */
   public static Insets getInsets(Object key)
   {
-    return (Insets) getLookAndFeel().getDefaults().getInsets(key);
+    return getLookAndFeelDefaults().getInsets(key);
   }
 
   /**
@@ -355,9 +462,15 @@
    */
   public static Insets getInsets(Object key, Locale locale)
   {
-    return (Insets) getLookAndFeel().getDefaults().getInsets(key, locale);
+    return getLookAndFeelDefaults().getInsets(key, locale);
   }
 
+  /**
+   * Returns an array containing information about the address@hidden 
LookAndFeel}s
+   * that are installed.
+   * 
+   * @return A list of the look and feels that are available (installed).
+   */
   public static LookAndFeelInfo[] getInstalledLookAndFeels()
   {
     return installed;
@@ -365,7 +478,7 @@
 
   public static int getInt(Object key)
   {
-    Integer x = (Integer) getLookAndFeel().getDefaults().get(key);
+    Integer x = (Integer) getLookAndFeelDefaults().get(key);
     if (x == null)
       return 0;
     return x.intValue();
@@ -373,24 +486,33 @@
 
   public static int getInt(Object key, Locale locale)
   {
-    Integer x = (Integer) getLookAndFeel().getDefaults().get(key, locale);
+    Integer x = (Integer) getLookAndFeelDefaults().get(key, locale);
     if (x == null)
       return 0;
     return x.intValue();
   }
 
+  /**
+   * Returns the current look and feel (which may be <code>null</code>).
+   * 
+   * @return The current look and feel.
+   * 
+   * @see #setLookAndFeel(LookAndFeel)
+   */
   public static LookAndFeel getLookAndFeel()
   {
-    return look_and_feel;
+    return currentLookAndFeel;
   }
 
   /**
    * Returns the <code>UIDefaults</code> table of the currently active
    * look and feel.
+   * 
+   * @return The address@hidden UIDefaults} for the current address@hidden 
LookAndFeel}.
    */
   public static UIDefaults getLookAndFeelDefaults()
   {
-    return getLookAndFeel().getDefaults();
+    return currentUIDefaults;
   }
 
   /**
@@ -398,7 +520,7 @@
    */
   public static String getString(Object key)
   {
-    return (String) getLookAndFeel().getDefaults().get(key);
+    return (String) getLookAndFeelDefaults().get(key);
   }
   
   /**
@@ -406,13 +528,17 @@
    */
   public static String getString(Object key, Locale locale)
   {
-    return (String) getLookAndFeel().getDefaults().get(key, locale);
+    return (String) getLookAndFeelDefaults().get(key, locale);
   }
   
   /**
-   * Returns the name of the LookAndFeel class that implements the
+   * Returns the name of the address@hidden LookAndFeel} class that implements 
the
    * native systems look and feel if there is one, otherwise the name
    * of the default cross platform LookAndFeel class.
+   * 
+   * @return The fully qualified class name for the system look and feel.
+   * 
+   * @see #getCrossPlatformLookAndFeelClassName()
    */
   public static String getSystemLookAndFeelClassName()
   {
@@ -420,18 +546,26 @@
   }
 
   /**
-   * Returns the Look and Feel object that renders the target component.
+   * Returns UI delegate from the current address@hidden LookAndFeel} that 
renders the 
+   * target component.
+   * 
+   * @param target  the target component.
    */
   public static ComponentUI getUI(JComponent target)
   {
-    return getDefaults().getUI(target);
+    return getLookAndFeelDefaults().getUI(target);
   }
 
   /**
    * Creates a new look and feel and adds it to the current array.
+   * 
+   * @param name  the look and feel name.
+   * @param className  the fully qualified name of the class that implements 
the
+   *                   look and feel.
    */
   public static void installLookAndFeel(String name, String className)
   {
+    installLookAndFeel(new LookAndFeelInfo(name, className));
   }
 
   /**
@@ -440,6 +574,7 @@
    */
   public static void installLookAndFeel(LookAndFeelInfo info)
   {
+    // FIXME: not yet implemented
   }
 
   /**
@@ -447,7 +582,7 @@
    */
   public static Object put(Object key, Object value)
   {
-    return getLookAndFeel().getDefaults().put(key,value);
+    return getLookAndFeelDefaults().put(key,value);
   }
 
   /**
@@ -455,32 +590,56 @@
    */
   public static void setInstalledLookAndFeels(UIManager.LookAndFeelInfo[] 
infos)
   {
+    // FIXME: not yet implemented.
   }
   
   /**
-   * Set the current default look.
+   * Sets the current address@hidden LookAndFeel}.
+   * 
+   * @param newLookAndFeel  the new look and feel (<code>null</code> 
permitted).
+   * 
+   * @throws UnsupportedLookAndFeelException if the look and feel is not 
+   *         supported on the current platform.
+   * 
+   * @see LookAndFeel#isSupportedLookAndFeel()
    */
   public static void setLookAndFeel(LookAndFeel newLookAndFeel)
     throws UnsupportedLookAndFeelException
   {
-    if (! newLookAndFeel.isSupportedLookAndFeel())
+    if (newLookAndFeel != null && ! newLookAndFeel.isSupportedLookAndFeel())
       throw new UnsupportedLookAndFeelException(newLookAndFeel.getName());
     
-    if (look_and_feel != null)
-      look_and_feel.uninitialize();
+    LookAndFeel oldLookAndFeel = currentLookAndFeel;
+    if (oldLookAndFeel != null)
+      oldLookAndFeel.uninitialize();
 
     // Set the current default look and feel using a LookAndFeel object. 
-    look_and_feel = newLookAndFeel;
-    look_and_feel.initialize();
-       
+    currentLookAndFeel = newLookAndFeel;
+    if (newLookAndFeel != null)
+      {
+        newLookAndFeel.initialize();
+        currentUIDefaults = newLookAndFeel.getDefaults();
+      }
+    else
+      {
+        currentUIDefaults = null;    
+      }
+    listeners.firePropertyChange("lookAndFeel", oldLookAndFeel, 
newLookAndFeel);
     //revalidate();
     //repaint();
   }
 
   /**
    * Set the current default look and feel using a class name.
+   * 
+   * @param className  the look and feel class name.
+   * 
+   * @throws UnsupportedLookAndFeelException if the look and feel is not 
+   *         supported on the current platform.
+   * 
+   * @see LookAndFeel#isSupportedLookAndFeel()
    */
-  public static void setLookAndFeel (String className)
+  public static void setLookAndFeel(String className)
     throws ClassNotFoundException, InstantiationException, 
IllegalAccessException,
     UnsupportedLookAndFeelException
   {