Bug 122756 [Viewers] Support for TreePath based content providers
Now that the JFace tree viewer supports the notion of a tree path, it would be benefitial if this information was made available to content providers and label providers. The particular scenario that requires this is team views that include change sets. A view can display multiple change sets and a single model element may be included in multiple change sets. In 3.2, we are using the common navigator framework to allow model providers to display their models in a team operation. Having a tree path based content provider would allow the logical model display to be intermixed with change sets. Without this support, team providers would most likely need to support two views, one which shows resources and change sets and another that shows the effects of the operation on the logical model.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
/**
     * Constant indicating that all levels of the tree should be expanded or
     * collapsed.
     * 
     * @see #expandToLevel
     * @see #collapseToLevel
     */
    public static final int ALL_LEVELS = -1;
    /**
     * List of registered tree listeners (element type: <code>TreeListener</code>). */
    private ListenerList treeListeners = new ListenerList();
    /**
     * The level to which the tree is automatically expanded each time the
     * viewer's input is changed (that is, by <code>setInput</code>). A
     * value of 0 means that auto-expand is off.
     * 
     * @see #setAutoExpandLevel
     */
    private int expandToLevel = 0;
    /**
     * Safe runnable used to update an item.
     */
    class UpdateItemSafeRunnable extends SafeRunnable {
        private Object element;
        private Item item;
        UpdateItemSafeRunnable(Item item, Object element) {
            this.item = item;
            this.element = element;
        }