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comparison dwtx/jface/text/link/TabStopIterator.d @ 129:eb30df5ca28b

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Added JFace Text sources
author Frank Benoit <benoit@tionex.de>
date Sat, 23 Aug 2008 19:10:48 +0200
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128:8df1d4193877 129:eb30df5ca28b
1 /*******************************************************************************
2 * Copyright (c) 2000, 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.text.link.TabStopIterator;
14
15 import dwt.dwthelper.utils;
16
17 import java.util.ArrayList;
18 import java.util.Collections;
19 import java.util.Comparator;
20 import java.util.Iterator;
21 import java.util.List;
22 import java.util.NoSuchElementException;
23
24 import dwtx.core.runtime.Assert;
25 import dwtx.jface.text.Position;
26
27
28
29 /**
30 * Iterator that leaps over the double occurrence of an element when switching from forward
31 * to backward iteration that is shown by <code>ListIterator</code>.
32 * <p>
33 * Package private, only for use by LinkedModeUI.
34 * </p>
35 * @since 3.0
36 */
37 class TabStopIterator {
38 /**
39 * Comparator for <code>LinkedPosition</code>s. If the sequence number of two positions is equal, the
40 * offset is used.
41 */
42 private static class SequenceComparator : Comparator {
43
44 /**
45 * {@inheritDoc}
46 *
47 * <p><code>o1</code> and <code>o2</code> are required to be instances
48 * of <code>LinkedPosition</code>.</p>
49 */
50 public int compare(Object o1, Object o2) {
51 LinkedPosition p1= (LinkedPosition)o1;
52 LinkedPosition p2= (LinkedPosition)o2;
53 int i= p1.getSequenceNumber() - p2.getSequenceNumber();
54 if (i !is 0)
55 return i;
56 return p1.getOffset() - p2.getOffset();
57 }
58
59 }
60
61 /** The comparator to sort the list of positions. */
62 private static final Comparator fComparator= new SequenceComparator();
63
64 /** The iteration sequence. */
65 private final ArrayList fList;
66 /** The size of <code>fList</code>. */
67 private int fSize;
68 /** Index of the current element, to the first one initially. */
69 private int fIndex;
70 /** Cycling property. */
71 private bool fIsCycling= false;
72
73 TabStopIterator(List positionSequence) {
74 Assert.isNotNull(positionSequence);
75 fList= new ArrayList(positionSequence);
76 Collections.sort(fList, fComparator);
77 fSize= fList.size();
78 fIndex= -1;
79 Assert.isTrue(fSize > 0);
80 }
81
82 bool hasNext(LinkedPosition current) {
83 return getNextIndex(current) !is fSize;
84 }
85
86 private int getNextIndex(LinkedPosition current) {
87 if (current !is null && fList.get(fIndex) !is current)
88 return findNext(current);
89 else if (fIsCycling && fIndex is fSize - 1)
90 return 0;
91 else
92 // default: increase
93 return fIndex + 1;
94 }
95
96 /**
97 * Finds the closest position in the iteration set that follows after
98 * <code>current</code> and sets <code>fIndex</code> accordingly. If <code>current</code>
99 * is in the iteration set, the next in turn is chosen.
100 *
101 * @param current the current position
102 * @return <code>true</code> if there is a next position, <code>false</code> otherwise
103 */
104 private int findNext(LinkedPosition current) {
105 Assert.isNotNull(current);
106 // if the position is in the iteration set, jump to the next one
107 int index= fList.indexOf(current);
108 if (index !is -1) {
109 if (fIsCycling && index is fSize - 1)
110 return 0;
111 return index + 1;
112 }
113
114 // index is -1
115
116 // find the position that follows closest to the current position
117 LinkedPosition found= null;
118 for (Iterator it= fList.iterator(); it.hasNext(); ) {
119 LinkedPosition p= (LinkedPosition) it.next();
120 if (p.offset > current.offset)
121 if (found is null || found.offset > p.offset)
122 found= p;
123 }
124
125 if (found !is null) {
126 return fList.indexOf(found);
127 } else if (fIsCycling) {
128 return 0;
129 } else
130 return fSize;
131 }
132
133 bool hasPrevious(LinkedPosition current) {
134 return getPreviousIndex(current) !is -1;
135 }
136
137 private int getPreviousIndex(LinkedPosition current) {
138 if (current !is null && fList.get(fIndex) !is current)
139 return findPrevious(current);
140 else if (fIsCycling && fIndex is 0)
141 return fSize - 1;
142 else
143 return fIndex - 1;
144 }
145
146 /**
147 * Finds the closest position in the iteration set that precedes
148 * <code>current</code>. If <code>current</code>
149 * is in the iteration set, the previous in turn is chosen.
150 *
151 * @param current the current position
152 * @return the index of the previous position
153 */
154 private int findPrevious(LinkedPosition current) {
155 Assert.isNotNull(current);
156 // if the position is in the iteration set, jump to the next one
157 int index= fList.indexOf(current);
158 if (index !is -1) {
159 if (fIsCycling && index is 0)
160 return fSize - 1;
161 return index - 1;
162 }
163
164 // index is -1
165
166 // find the position that follows closest to the current position
167 LinkedPosition found= null;
168 for (Iterator it= fList.iterator(); it.hasNext(); ) {
169 LinkedPosition p= (LinkedPosition) it.next();
170 if (p.offset < current.offset)
171 if (found is null || found.offset < p.offset)
172 found= p;
173 }
174 if (found !is null) {
175 return fList.indexOf(found);
176 } else if (fIsCycling) {
177 return fSize - 1;
178 } else
179 return -1;
180 }
181
182 LinkedPosition next(LinkedPosition current) {
183 if (!hasNext(current))
184 throw new NoSuchElementException();
185 return (LinkedPosition) fList.get(fIndex= getNextIndex(current));
186 }
187
188 LinkedPosition previous(LinkedPosition current) {
189 if (!hasPrevious(current))
190 throw new NoSuchElementException();
191 return (LinkedPosition) fList.get(fIndex= getPreviousIndex(current));
192 }
193
194 void setCycling(bool mode) {
195 fIsCycling= mode;
196 }
197
198 void addPosition(Position position) {
199 fList.add(fSize++, position);
200 Collections.sort(fList, fComparator);
201 }
202
203 void removePosition(Position position) {
204 if (fList.remove(position))
205 fSize--;
206 }
207
208 /**
209 * @return Returns the isCycling.
210 */
211 bool isCycling() {
212 return fIsCycling;
213 }
214
215 LinkedPosition[] getPositions() {
216 return (LinkedPosition[]) fList.toArray(new LinkedPosition[fSize]);
217 }
218 }