--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/viewers/ViewerUpdater.d	Tue Apr 14 11:35:29 2009 +0200
@@ -0,0 +1,125 @@
+/*******************************************************************************
+ * Copyright (c) 2008 Matthew Hall 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:
+ *     Matthew Hall - initial API and implementation (bug 226765)
+ ******************************************************************************/
+
+module org.eclipse.jface.internal.databinding.viewers.ViewerUpdater;
+
+import java.lang.all;
+
+import org.eclipse.jface.util.Util;
+import org.eclipse.jface.viewers.IElementComparer;
+import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.jface.viewers.StructuredViewer;
+
+/**
+ * NON-API - An interface for updating a viewer's elements.
+ * 
+ * @since 1.2
+ */
+public abstract class ViewerUpdater {
+    private final StructuredViewer viewer;
+
+    /**
+     * Constructs a ViewerUpdater for updating the specified viewer.
+     * 
+     * @param viewer
+     *            the viewer which will be updated through this instance.
+     */
+    protected this(StructuredViewer viewer) {
+        this.viewer = viewer;
+    }
+
+    /**
+     * Insert the element into the viewer at the specified position.
+     * 
+     * @param element
+     *            the element to add
+     * @param position
+     *            the position of the element
+     */
+    public abstract void insert(Object element, int position);
+
+    /**
+     * Remove the element from the viewer
+     * 
+     * @param element
+     *            the element to remove
+     * @param position
+     *            the position of the element
+     */
+    public abstract void remove(Object element, int position);
+
+    /**
+     * Replace the specified element at the given position with the new element.
+     * 
+     * @param oldElement
+     *            the element being replaced
+     * @param newElement
+     *            the element that replaces <code>oldElement</code>
+     * @param position
+     *            the position of the element being replaced.
+     */
+    public void replace(Object oldElement, Object newElement, int position) {
+        remove(oldElement, position);
+        insert(newElement, position);
+    }
+
+    /**
+     * Moves the specified element from the specified old position to the
+     * specified new position. No action is taken if the viewer has a sorter or
+     * filter(s).
+     * 
+     * @param element
+     *            the element being moved
+     * @param oldPosition
+     *            the position of the element before it is moved
+     * @param newPosition
+     *            the position of the element after it is moved
+     */
+    public void move(Object element, int oldPosition, int newPosition) {
+        if (viewer.getComparator() is null && viewer.getFilters().length is 0) {
+            IStructuredSelection selection = cast(IStructuredSelection) viewer
+                    .getSelection();
+
+            remove(element, oldPosition);
+            insert(element, newPosition);
+
+            // Preserve selection
+            if (!selection.isEmpty()) {
+                IElementComparer comparer = viewer.getComparer();
+                Object[] selectedElements = selection.toArray();
+                for (int i = 0; i < selectedElements.length; i++) {
+                    if (comparer is null ? Util.equals(element,
+                            selectedElements[i]) : comparer.equals(element,
+                            selectedElements[i])) {
+                        viewer.setSelection(selection);
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Adds the elements to the viewer.
+     * 
+     * @param elements
+     *            the elements to add
+     */
+    public abstract void add(Object[] elements);
+
+    /**
+     * Removes the elements from the viewer
+     * 
+     * @param elements
+     *            the elements to remove
+     */
+    public abstract void remove(Object[] elements);
+}