[cp-patches] RFC: JTree memory leak

[Francis Kung]

Hi,

The attached patch fixes a memory leak in the JTree, changing a
Hashtable into a WeakHashMap.

I'm not too familiar with this class, so I don't know if this is the
best way to fix it (or if this even breaks something!), and I'd
appreciate any comments or approval for this patch.

Thanks,
Francis


Index: javax/swing/JTree.java
===================================================================
RCS file: /cvsroot/classpath/classpath/javax/swing/JTree.java,v
retrieving revision 1.77
diff -u -r1.77 JTree.java
--- javax/swing/JTree.java	18 Oct 2006 18:46:25 -0000	1.77
+++ javax/swing/JTree.java	2 Nov 2006 21:02:28 -0000
@@ -52,6 +52,7 @@
 import java.util.Iterator;
 import java.util.Locale;
 import java.util.Vector;
+import java.util.WeakHashMap;
 
 import javax.accessibility.Accessible;
 import javax.accessibility.AccessibleAction;
@@ -1400,7 +1401,7 @@
    * TreePath of a note to to its state. Valid states are EXPANDED and
    * COLLAPSED. Nodes not in this Hashtable are assumed state COLLAPSED.
    */
-  private Hashtable nodeStates = new Hashtable();
+  private WeakHashMap nodeStates = new WeakHashMap();
 
   protected transient TreeCellEditor cellEditor;
 
@@ -1505,7 +1506,7 @@
     setSelectionModel( new DefaultTreeSelectionModel() );
     
     // The root node appears expanded by default.
-    nodeStates = new Hashtable();
+    nodeStates = new WeakHashMap();
 
     // The cell renderer gets set by the UI.
     cellRenderer = null;
@@ -2757,12 +2758,12 @@
     if (parent == null)
       return null;
 
-    Enumeration nodes = nodeStates.keys();
+    Iterator nodes = nodeStates.keySet().iterator();
     Vector result = new Vector();
 
-    while (nodes.hasMoreElements())
+    while (nodes.hasNext())
       {
-        TreePath path = (TreePath) nodes.nextElement();
+        TreePath path = (TreePath) nodes.next();
 
         if (path.isDescendant(parent))
           result.addElement(path);
@@ -2903,11 +2904,11 @@
    */
   public Enumeration getExpandedDescendants(TreePath path)
   {
-    Enumeration paths = nodeStates.keys();
+    Iterator paths = nodeStates.keySet().iterator();
     Vector relevantPaths = new Vector();
-    while (paths.hasMoreElements())
+    while (paths.hasNext())
       {
-        TreePath nextPath = (TreePath) paths.nextElement();
+        TreePath nextPath = (TreePath) paths.next();
         if (nodeStates.get(nextPath) == EXPANDED
             && path.isDescendant(nextPath))
           {