| /******************************************************************************* |
| * Copyright (c) 2005, 2006 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 |
| *******************************************************************************/ |
| package org.eclipse.jface.viewers; |
| |
| /** |
| * The ILazyTreePathContentProvider is a tree path-based content provider for |
| * tree viewers created using the SWT.VIRTUAL flag that only wish to return |
| * their contents as they are queried. |
| * |
| * @since 3.3 |
| */ |
| public interface ILazyTreePathContentProvider extends IContentProvider { |
| /** |
| * Called when a previously-blank item becomes visible in the TreeViewer. If |
| * the content provider knows the child element for the given parent at this |
| * index, it should respond by calling |
| * {@link TreeViewer#replace(Object, int, Object)}. The content provider |
| * should also update the child count for any replaced element by calling |
| * {@link TreeViewer#setChildCount(Object, int)}. If the given current child |
| * count is already correct, setChildCount does not have to be called since |
| * a call to replace will not change the child count. |
| * |
| * <strong>NOTE</strong> #updateElement(int index) can be used to determine |
| * selection values. If TableViewer#replace(Object, int) is not called |
| * before returning from this method, selections may have missing or stale |
| * elements. In this situation it is suggested that the selection is asked |
| * for again after replace() has been called. |
| * |
| * @param parentPath |
| * The tree path of parent of the element, or if the |
| * element to update is a root element, an empty tree path |
| * @param index |
| * The index of the element to update in the tree |
| */ |
| public void updateElement(TreePath parentPath, int index); |
| |
| /** |
| * Called when the TreeViewer needs an up-to-date child count for the given |
| * tree path, for example from {@link TreeViewer#refresh()} and |
| * {@link TreeViewer#setInput(Object)}. If the content provider knows the |
| * element at the given tree path, it should respond by calling |
| * {@link TreeViewer#setChildCount(Object, int)}. If the given current |
| * child count is already correct, no action has to be taken by this content |
| * provider. |
| * |
| * @param treePath |
| * The tree path for which an up-to-date child count is needed, or |
| * if the number of root elements is requested, the empty tree path |
| * @param currentChildCount |
| * The current child count for the element that needs updating |
| */ |
| public void updateChildCount(TreePath treePath, int currentChildCount); |
| |
| /** |
| * Called when the TreeViewer needs up-to-date information whether the node |
| * at the given tree path can be expanded. If the content provider knows the |
| * element at the given tree path, it should respond by calling |
| * {@link TreeViewer#setHasChildren(Object, boolean)}. The content provider |
| * may also choose to call {@link TreeViewer#setChildCount(Object, int)} |
| * instead if it knows the number of children. |
| * |
| * <p> |
| * Intended as an optimization for when the viewer does not need the actual |
| * children. Clients may be able to implement this more efficiently than |
| * <code>updateChildCount</code>. |
| * </p> |
| * |
| * @param path |
| * The tree path for which up-to-date information about children |
| * is needed |
| */ |
| public void updateHasChildren(TreePath path); |
| |
| /** |
| * Return the possible parent paths for the given element. An empty array |
| * can be returned if the paths cannot be computed. In this case the |
| * tree-structured viewer can't expand a given node correctly if requested. |
| * If the element is a potential child of the input of the viewer, an empty |
| * tree path should be an entry in the returned array. |
| * |
| * @param element |
| * the element |
| * @return the possible parent paths for the given element |
| */ |
| public TreePath[] getParents(Object element); |
| } |