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comparison dwtx/jface/viewers/ILazyTreePathContentProvider.d @ 10:b6c35faf97c8

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Viewers
author Frank Benoit <benoit@tionex.de>
date Mon, 31 Mar 2008 00:47:19 +0200
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1 /*******************************************************************************
2 * Copyright (c) 2005, 2006 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 * Port to the D programming language:
11 * Frank Benoit <benoit@tionex.de>
12 *******************************************************************************/
13 module dwtx.jface.viewers.ILazyTreePathContentProvider;
14
15 import dwtx.jface.viewers.IContentProvider;
16 import dwtx.jface.viewers.TreePath;
17
18 import dwt.dwthelper.utils;
19
20 /**
21 * The ILazyTreePathContentProvider is a tree path-based content provider for
22 * tree viewers created using the DWT.VIRTUAL flag that only wish to return
23 * their contents as they are queried.
24 *
25 * @since 3.3
26 */
27 public interface ILazyTreePathContentProvider : IContentProvider {
28 /**
29 * Called when a previously-blank item becomes visible in the TreeViewer. If
30 * the content provider knows the child element for the given parent at this
31 * index, it should respond by calling
32 * {@link TreeViewer#replace(Object, int, Object)}. The content provider
33 * should also update the child count for any replaced element by calling
34 * {@link TreeViewer#setChildCount(Object, int)}. If the given current child
35 * count is already correct, setChildCount does not have to be called since
36 * a call to replace will not change the child count.
37 *
38 * <strong>NOTE</strong> #updateElement(int index) can be used to determine
39 * selection values. If TableViewer#replace(Object, int) is not called
40 * before returning from this method, selections may have missing or stale
41 * elements. In this situation it is suggested that the selection is asked
42 * for again after replace() has been called.
43 *
44 * @param parentPath
45 * The tree path of parent of the element, or if the
46 * element to update is a root element, an empty tree path
47 * @param index
48 * The index of the element to update in the tree
49 */
50 public void updateElement(TreePath parentPath, int index);
51
52 /**
53 * Called when the TreeViewer needs an up-to-date child count for the given
54 * tree path, for example from {@link TreeViewer#refresh()} and
55 * {@link TreeViewer#setInput(Object)}. If the content provider knows the
56 * element at the given tree path, it should respond by calling
57 * {@link TreeViewer#setChildCount(Object, int)}. If the given current
58 * child count is already correct, no action has to be taken by this content
59 * provider.
60 *
61 * @param treePath
62 * The tree path for which an up-to-date child count is needed, or
63 * if the number of root elements is requested, the empty tree path
64 * @param currentChildCount
65 * The current child count for the element that needs updating
66 */
67 public void updateChildCount(TreePath treePath, int currentChildCount);
68
69 /**
70 * Called when the TreeViewer needs up-to-date information whether the node
71 * at the given tree path can be expanded. If the content provider knows the
72 * element at the given tree path, it should respond by calling
73 * {@link TreeViewer#setHasChildren(Object, bool)}. The content provider
74 * may also choose to call {@link TreeViewer#setChildCount(Object, int)}
75 * instead if it knows the number of children.
76 *
77 * <p>
78 * Intended as an optimization for when the viewer does not need the actual
79 * children. Clients may be able to implement this more efficiently than
80 * <code>updateChildCount</code>.
81 * </p>
82 *
83 * @param path
84 * The tree path for which up-to-date information about children
85 * is needed
86 */
87 public void updateHasChildren(TreePath path);
88
89 /**
90 * Return the possible parent paths for the given element. An empty array
91 * can be returned if the paths cannot be computed. In this case the
92 * tree-structured viewer can't expand a given node correctly if requested.
93 * If the element is a potential child of the input of the viewer, an empty
94 * tree path should be an entry in the returned array.
95 *
96 * @param element
97 * the element
98 * @return the possible parent paths for the given element
99 */
100 public TreePath[] getParents(Object element);
101 }