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comparison org.eclipse.core.databinding/src/org/eclipse/core/databinding/observable/list/ListDiff.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) 2006, 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 * Matthew Hall - bug 208858
11 *******************************************************************************/
12
13 module org.eclipse.core.databinding.observable.list.ListDiff;
14
15 import java.lang.all;
16
17 import org.eclipse.core.internal.databinding.Util;
18
19 /**
20 * Object describing a diff between two lists.
21 *
22 * @since 1.0
23 */
24 public abstract class ListDiff {
25
26 /**
27 * Returns a ListDiffEntry array representing the differences in the list,
28 * in the order they are to be processed.
29 *
30 * @return a ListDiffEntry array representing the differences in the list,
31 * in the order they are to be processed.
32 */
33 public abstract ListDiffEntry[] getDifferences();
34
35 /**
36 * Traverses the {@link #getDifferences()} array, calling the appropriate
37 * method in <code>visitor</code> for each difference.
38 * <ol>
39 * <li>{@link ListDiffVisitor#handleReplace(int, Object, Object)} is called
40 * whenever a remove entry is immediately followed by an add entry which
41 * shares the same list index.
42 * <li>{@link ListDiffVisitor#handleMove(int, int, Object)} is called
43 * whenever a remove entry is immediately followed by an add entry with an
44 * equivalent element.
45 * <li>{@link ListDiffVisitor#handleRemove(int, Object)} is called whenever
46 * a remove entry does not match conditions 1 or 2.
47 * <li>{@link ListDiffVisitor#handleAdd(int, Object)} is called whenever an
48 * add entry does not match conditions in 1 or 2.
49 * </ol>
50 *
51 * @param visitor
52 * the visitor to receive callbacks.
53 * @see ListDiffVisitor
54 * @since 1.1
55 */
56 public void accept(ListDiffVisitor visitor) {
57 ListDiffEntry[] differences = getDifferences();
58 for (int i = 0; i < differences.length; i++) {
59 ListDiffEntry entry = differences[i];
60 int position = entry.getPosition();
61 Object element = entry.getElement();
62 bool addition = entry.isAddition();
63
64 if (!addition && i + 1 < differences.length) {
65 ListDiffEntry entry2 = differences[i + 1];
66 if (entry2.isAddition()) {
67 int position2 = entry2.getPosition();
68 Object element2 = entry2.getElement();
69 if (position is position2) {
70 visitor.handleReplace(position, element, element2);
71 i++;
72 continue;
73 }
74 if (Util.equals(element, element2)) {
75 visitor.handleMove(position, position2, element);
76 i++;
77 continue;
78 }
79 }
80 }
81 if (addition)
82 visitor.handleAdd(position, element);
83 else
84 visitor.handleRemove(position, element);
85 }
86 }
87
88 /**
89 * @see java.lang.Object#toString()
90 */
91 public String toString() {
92 ListDiffEntry[] differences = getDifferences();
93 StringBuffer buffer = new StringBuffer();
94 buffer.append(getClass().getName());
95
96 if (differences is null || differences.length is 0) {
97 buffer
98 .append("{}"); //$NON-NLS-1$
99 } else {
100 buffer
101 .append("{"); //$NON-NLS-1$
102
103 for (int i = 0; i < differences.length; i++) {
104 if (i > 0)
105 buffer.append(", "); //$NON-NLS-1$
106
107 buffer
108 .append("difference[") //$NON-NLS-1$
109 .append(i)
110 .append("] [") //$NON-NLS-1$
111 .append(differences[i] !is null ? differences[i].toString() : "null") //$NON-NLS-1$
112 .append("]"); //$NON-NLS-1$
113 }
114 buffer.append("}"); //$NON-NLS-1$
115 }
116
117 return buffer.toString();
118 }
119 }