| /******************************************************************************* |
| * 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 ILazyTreeContentProvider is the content provider for tree viewers created |
| * using the SWT.VIRTUAL flag that only wish to return their contents as they |
| * are queried. |
| * |
| * @since 3.2 |
| */ |
| public interface ILazyTreeContentProvider 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 parent |
| * The parent of the element, or the viewer's input if the |
| * element to update is a root element |
| * @param index |
| * The index of the element to update in the tree |
| */ |
| public void updateElement(Object parent, int index); |
| |
| /** |
| * Called when the TreeViewer needs an up-to-date child count for the given |
| * element, for example from {@link TreeViewer#refresh()} and |
| * {@link TreeViewer#setInput(Object)}. If the content provider knows the |
| * given element, 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 element |
| * The element for which an up-to-date child count is needed, or |
| * the viewer's input if the number of root elements is requested |
| * @param currentChildCount |
| * The current child count for the element that needs updating |
| */ |
| public void updateChildCount(Object element, int currentChildCount); |
| |
| /** |
| * Returns the parent for the given element, or <code>null</code> |
| * indicating that the parent can't be computed. |
| * In this case the tree-structured viewer can't expand |
| * a given node correctly if requested. |
| * |
| * @param element the element |
| * @return the parent element, or <code>null</code> if it |
| * has none or if the parent cannot be computed |
| */ |
| public Object getParent(Object element); |
| } |