--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/draw2d/AncestorHelper.d	Sun Aug 03 00:52:14 2008 +0200
@@ -0,0 +1,189 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2005 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwtx.draw2d.AncestorHelper;
+
+import dwt.dwthelper.utils;
+import dwtx.dwtxhelper.Bean;
+
+import dwtx.draw2d.IFigure;
+import dwtx.draw2d.FigureListener;
+import dwtx.draw2d.AncestorListener;
+
+/**
+ * A helper object which tracks the parent chain hierarchy.
+ * @since 2.1
+ */
+class AncestorHelper
+    : PropertyChangeListener, FigureListener
+{
+
+/**
+ * The base figure whose ancestor chain is being observed.
+ */
+protected final IFigure base;
+/**
+ * The array of ancestor listeners.
+ */
+protected AncestorListener[] listeners;
+
+/**
+ * Constructs a new helper on the given base figure and starts listening to figure and
+ * property changes on the base figure's parent chain.  When no longer needed, the helper
+ * should be disposed.
+ * @since 2.1
+ * @param baseFigure
+ */
+public this(IFigure baseFigure) {
+    this.base = baseFigure;
+    addAncestors(baseFigure);
+}
+
+/**
+ * Appends a new listener to the list of listeners.
+ * @param listener the listener
+ */
+public void addAncestorListener(AncestorListener listener) {
+    if (listeners is null) {
+        listeners = new AncestorListener[1];
+        listeners[0] = listener;
+    } else {
+        int oldSize = listeners.length;
+        AncestorListener newListeners[] = new AncestorListener[oldSize + 1];
+        SimpleType!(AncestorListener).arraycopy(listeners, 0, newListeners, 0, oldSize);
+        newListeners[oldSize] = listener;
+        listeners = newListeners;
+    }
+}
+
+/**
+ * Hooks up internal listeners used for maintaining the proper figure listeners.
+ * @param rootFigure the root figure
+ */
+protected void addAncestors(IFigure rootFigure) {
+    for (IFigure ancestor = rootFigure;
+            ancestor !is null;
+            ancestor = ancestor.getParent()) {
+        ancestor.addFigureListener(this);
+        ancestor.addPropertyChangeListener("parent", this); //$NON-NLS-1$
+    }
+}
+
+/**
+ * Removes all internal listeners.
+ */
+public void dispose() {
+    removeAncestors(base);
+    listeners = null;
+}
+
+/**
+ * @see dwtx.draw2d.FigureListener#figureMoved(dwtx.draw2d.IFigure)
+ */
+public void figureMoved(IFigure ancestor) {
+    fireAncestorMoved(ancestor);
+}
+
+/**
+ * Fires notification to the listener list
+ * @param ancestor the figure which moved
+ */
+protected void fireAncestorMoved(IFigure ancestor) {
+    if (listeners is null)
+        return;
+    for (int i = 0; i < listeners.length; i++)
+        listeners[i].ancestorMoved(ancestor);
+}
+
+/**
+ * Fires notification to the listener list
+ * @param ancestor the figure which moved
+ */
+protected void fireAncestorAdded(IFigure ancestor) {
+    if (listeners is null)
+        return;
+    for (int i = 0; i < listeners.length; i++)
+        listeners[i].ancestorAdded(ancestor);
+}
+
+/**
+ * Fires notification to the listener list
+ * @param ancestor the figure which moved
+ */
+protected void fireAncestorRemoved(IFigure ancestor) {
+    if (listeners is null)
+        return;
+    for (int i = 0; i < listeners.length; i++)
+        listeners[i].ancestorRemoved(ancestor);
+}
+
+/**
+ * Returns the total number of listeners.
+ * @return the number of listeners
+ */
+public bool isEmpty() {
+    return listeners is null;
+}
+
+/**
+ * @see java.beans.PropertyChangeListener#propertyChange(java.beans.PropertyChangeEvent)
+ */
+public void propertyChange(PropertyChangeEvent event) {
+    if (event.getPropertyName().equals("parent")) { //$NON-NLS-1$
+        IFigure oldParent = cast(IFigure)event.getOldValue();
+        IFigure newParent = cast(IFigure)event.getNewValue();
+        if (oldParent !is null) {
+            removeAncestors(oldParent);
+            fireAncestorRemoved(oldParent);
+        }
+        if (newParent !is null) {
+            addAncestors(newParent);
+            fireAncestorAdded(newParent);
+        }
+    }
+}
+
+/**
+ * Removes the first occurence of the given listener
+ * @param listener the listener to remove
+ */
+public void removeAncestorListener(AncestorListener listener) {
+    if (listeners is null)
+        return;
+    for (int index = 0; index < listeners.length; index++)
+        if (listeners[index] is listener) {
+            int newSize = listeners.length - 1;
+            AncestorListener newListeners[] = null;
+            if (newSize !is 0) {
+                newListeners = new AncestorListener[newSize];
+                SimpleType!(AncestorListener).arraycopy(listeners, 0, newListeners, 0, index);
+                SimpleType!(AncestorListener).arraycopy(listeners, index + 1, newListeners, index, newSize - index);
+            }
+            listeners = newListeners;
+            return;
+        }
+}
+
+/**
+ * Unhooks listeners starting at the given figure
+ * @param rootFigure
+ */
+protected void removeAncestors(IFigure rootFigure) {
+    for (IFigure ancestor = rootFigure;
+                ancestor !is null;
+                ancestor = ancestor.getParent()) {
+        ancestor.removeFigureListener(this);
+        ancestor.removePropertyChangeListener("parent", this); //$NON-NLS-1$
+    }
+}
+
+}