Index: loaders/src/org/openide/loaders/FolderChildren.java
===================================================================
RCS file: /cvs/openide/loaders/src/org/openide/loaders/FolderChildren.java,v
retrieving revision 1.4
diff -u -r1.4 FolderChildren.java
--- loaders/src/org/openide/loaders/FolderChildren.java	26 May 2004 13:11:51 -0000	1.4
+++ loaders/src/org/openide/loaders/FolderChildren.java	5 Jun 2004 12:02:10 -0000
@@ -15,6 +15,8 @@
 
 import java.beans.*;
 import java.util.*;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
 
 import org.openide.ErrorManager;
 import org.openide.filesystems.FileObject;
@@ -29,7 +31,7 @@
 * @author Jaroslav Tulach
 */
 final class FolderChildren extends Children.Keys 
-implements PropertyChangeListener {
+implements PropertyChangeListener, ChangeListener {
     /** the folder */
     private DataFolder folder;
     /** filter of objects */
@@ -95,6 +97,14 @@
             return;
         }
     }
+    
+    public void stateChanged( ChangeEvent e ) {
+        // Filtering changed need to recompute children
+        setKeys( Collections.EMPTY_SET );
+        refreshChildren().schedule(0);
+        postClearTask();
+        return;
+    }
 
     /**
      * refreshRunnable holds references to the data object
@@ -198,6 +208,10 @@
     protected void addNotify () {
         // add as a listener for changes on nodes
         folder.addPropertyChangeListener (listener);
+        // add listener to the filter
+        if ( filter instanceof ChangeableDataFilter ) {
+            ((ChangeableDataFilter)filter).addChangeListener( this );
+        }
         // 
         active = true;
         // start the refresh task to compute the children
@@ -209,6 +223,10 @@
     protected void removeNotify () {
         // removes the listener
         folder.removePropertyChangeListener (listener);
+        // remove listener from filter
+        if ( filter instanceof ChangeableDataFilter ) {
+            ((ChangeableDataFilter)filter).removeChangeListener( this );
+        }
         //
         active = false;
         // we don't call the setKeys directly here because
Index: test/unit/src/org/openide/loaders/FolderChildrenTest.java
===================================================================
RCS file: /cvs/openide/test/unit/src/org/openide/loaders/FolderChildrenTest.java,v
retrieving revision 1.2
diff -u -r1.2 FolderChildrenTest.java
--- test/unit/src/org/openide/loaders/FolderChildrenTest.java	16 Oct 2002 06:09:25 -0000	1.2
+++ test/unit/src/org/openide/loaders/FolderChildrenTest.java	5 Jun 2004 12:02:11 -0000
@@ -16,6 +16,8 @@
 import java.io.IOException;
 import java.util.*;
 import javax.swing.SwingUtilities;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
 
 import org.openide.filesystems.*;
 import org.openide.loaders.*;
@@ -25,6 +27,8 @@
 import org.netbeans.junit.*;
 import java.util.Enumeration;
 import org.openide.nodes.Node;
+import org.openide.nodes.Children;
+
 
 public class FolderChildrenTest extends NbTestCase {
     public FolderChildrenTest() {
@@ -80,7 +84,33 @@
         assertTrue ("Second one is the same", last[1] == arr[1]);
         
     }
+    
+    public void testChangeableDataFilter() throws Exception {
+        setupSystemProperties();
+        
+        FileSystem fs = Repository.getDefault ().getDefaultFileSystem();
+        FileUtil.createData (fs.getRoot (), "BB/A.txt");
+        FileUtil.createData (fs.getRoot (), "BB/B.txt");
+        FileUtil.createData (fs.getRoot (), "BB/AA.txt");
+        FileUtil.createData (fs.getRoot (), "BB/BA.txt");
+        
+        
+        FileObject bb = fs.findResource("/BB");
+        
+        Filter filter = new Filter();
+        DataFolder folder = DataFolder.findFolder (bb);
+        
+        Children ch = folder.createNodeChildren( filter );        
+        Node[] arr = ch.getNodes (true);
+        
+        assertNodes( arr, new String[] { "A.txt", "AA.txt" } );
+        filter.fire();
+        arr = ch.getNodes (true);        
+        assertNodes( arr, new String[] { "B.txt", "BA.txt" } );
+        
+    }
 
+    
     public static class N1 extends org.openide.nodes.AbstractNode 
     implements Node.Cookie {
         public N1 () {
@@ -111,4 +141,53 @@
     
     public static final class N2 extends N1 {
     }
+
+    
+    private void assertNodes( Node[] nodes, String names[] ) {
+        
+        assertEquals( "Wrong number of nodes.", names.length, nodes.length );
+        
+        for( int i = 0; i < nodes.length; i++ ) {
+            System.out.println("Display Name :" + nodes[i].getName() + ":");            
+            assertEquals( "Wrong name at index " + i + ".", names[i], nodes[i].getName() );
+        }
+        
+    }
+    
+    private static class Filter implements ChangeableDataFilter  {
+
+        private boolean selectA = true;
+                    
+        ArrayList listeners = new ArrayList();
+        
+        public boolean acceptDataObject (DataObject obj) {
+            String fileName = obj.getPrimaryFile().getName();
+            boolean select = fileName.startsWith( "A" );            
+            select = selectA ? select : !select;
+            System.out.println("FILTERING " + fileName + " : " + select );
+            return select;
+        }
+        
+        public void addChangeListener( ChangeListener listener ) {
+            listeners.add( listener );
+        }
+        
+        public void removeChangeListener( ChangeListener listener ) {
+            listeners.remove( listener );
+        }
+        
+        public void fire( ) {
+        
+            selectA = !selectA;
+            
+            ChangeEvent che = new ChangeEvent( this );
+            
+            for( Iterator it = listeners.iterator(); it.hasNext(); ) {
+                ChangeListener chl = (ChangeListener)it.next();
+                chl.stateChanged( che );
+            }
+        }
+        
+    }
+    
 }