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comparison org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/viewers/TreeStructureAdvisor.d @ 78:0a55d2d5a946

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Added file for databinding
author Frank Benoit <benoit@tionex.de>
date Tue, 14 Apr 2009 11:35:29 +0200
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76:f05e6e8b2f2d 78:0a55d2d5a946
1 /*******************************************************************************
2 * Copyright (c) 2008 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 ******************************************************************************/
11 module org.eclipse.jface.databinding.viewers.TreeStructureAdvisor;
12
13 import java.lang.all;
14
15 /**
16 * Instances of this class can be used to improve accuracy and performance of an
17 * {@link ObservableListTreeContentProvider} or an
18 * {@link ObservableSetTreeContentProvider}. This class is intended to be
19 * subclassed by clients.
20 *
21 * @since 1.2
22 *
23 */
24 public abstract class TreeStructureAdvisor {
25
26 /**
27 * Returns the parent for the given element, or <code>null</code>
28 * indicating that the parent can't be computed. In this case the
29 * tree-structured viewer can't expand a given node correctly if requested.
30 * The default implementation returns null; clients should override.
31 *
32 * @param element
33 * the element
34 * @return the parent element, or <code>null</code> if it has none or if
35 * the parent cannot be computed
36 */
37 public Object getParent(Object element) {
38 return null;
39 }
40
41 /**
42 * Returns whether the given element has children, or <code>null</code> if
43 * the actual children collection should be consulted. The default
44 * implementation returns null; clients should override.
45 * <p>
46 * Intended as an optimization for when the viewer does not need the actual
47 * children. Clients may be able to implement this more efficiently than
48 * <code>getChildren</code>.
49 * </p>
50 *
51 * @param element
52 * the element
53 * @return <code>Boolean.TRUE</code> if the given element has children,
54 * <code>Boolean.FALSE</code> if it has no children, or
55 * <code>null</code> if the children collection should be
56 * consulted.
57 */
58 public Boolean hasChildren(Object element) {
59 return null;
60 }
61
62 }