1 /*
2 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 /*
27 * (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
28 * (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
29 *
30 * The original version of this source code and documentation
31 * is copyrighted and owned by Taligent, Inc., a wholly-owned
32 * subsidiary of IBM. These materials are provided under terms
33 * of a License Agreement between Taligent and Sun. This technology
34 * is protected by multiple US and International patents.
35 *
36 * This notice and attribution to Taligent may not be removed.
37 * Taligent is a registered trademark of Taligent, Inc.
38 *
39 */
40
41 package java.text;
42
43 /**
44 * <code>StringCharacterIterator</code> implements the
45 * <code>CharacterIterator</code> protocol for a <code>String</code>.
46 * The <code>StringCharacterIterator</code> class iterates over the
47 * entire <code>String</code>.
48 *
49 * @see CharacterIterator
50 */
51
52 public final class StringCharacterIterator implements CharacterIterator
53 {
54 private String text;
55 private int begin;
56 private int end;
57 // invariant: begin <= pos <= end
58 private int pos;
59
60 /**
61 * Constructs an iterator with an initial index of 0.
62 *
63 * @param text the {@code String} to be iterated over
64 */
65 public StringCharacterIterator(String text)
66 {
67 this(text, 0);
68 }
69
70 /**
71 * Constructs an iterator with the specified initial index.
72 *
73 * @param text The String to be iterated over
74 * @param pos Initial iterator position
75 */
76 public StringCharacterIterator(String text, int pos)
77 {
78 this(text, 0, text.length(), pos);
79 }
80
81 /**
82 * Constructs an iterator over the given range of the given string, with the
83 * index set at the specified position.
84 *
85 * @param text The String to be iterated over
86 * @param begin Index of the first character
87 * @param end Index of the character following the last character
88 * @param pos Initial iterator position
89 */
90 public StringCharacterIterator(String text, int begin, int end, int pos) {
91 if (text == null)
92 throw new NullPointerException();
93 this.text = text;
94
95 if (begin < 0 || begin > end || end > text.length())
96 throw new IllegalArgumentException("Invalid substring range");
97
98 if (pos < begin || pos > end)
99 throw new IllegalArgumentException("Invalid position");
100
101 this.begin = begin;
102 this.end = end;
103 this.pos = pos;
104 }
105
106 /**
107 * Reset this iterator to point to a new string. This package-visible
108 * method is used by other java.text classes that want to avoid allocating
109 * new StringCharacterIterator objects every time their setText method
110 * is called.
111 *
112 * @param text The String to be iterated over
113 * @since 1.2
114 */
115 public void setText(String text) {
116 if (text == null)
117 throw new NullPointerException();
118 this.text = text;
119 this.begin = 0;
120 this.end = text.length();
121 this.pos = 0;
122 }
123
124 /**
125 * Implements CharacterIterator.first() for String.
126 * @see CharacterIterator#first
127 */
128 public char first()
129 {
130 pos = begin;
131 return current();
132 }
133
134 /**
135 * Implements CharacterIterator.last() for String.
136 * @see CharacterIterator#last
137 */
138 public char last()
139 {
140 if (end != begin) {
141 pos = end - 1;
142 } else {
143 pos = end;
144 }
145 return current();
146 }
147
148 /**
149 * Implements CharacterIterator.setIndex() for String.
150 * @see CharacterIterator#setIndex
151 */
152 public char setIndex(int p)
153 {
154 if (p < begin || p > end)
155 throw new IllegalArgumentException("Invalid index");
156 pos = p;
157 return current();
158 }
159
160 /**
161 * Implements CharacterIterator.current() for String.
162 * @see CharacterIterator#current
163 */
164 public char current()
165 {
166 if (pos >= begin && pos < end) {
167 return text.charAt(pos);
168 }
169 else {
170 return DONE;
171 }
172 }
173
174 /**
175 * Implements CharacterIterator.next() for String.
176 * @see CharacterIterator#next
177 */
178 public char next()
179 {
180 if (pos < end - 1) {
181 pos++;
182 return text.charAt(pos);
183 }
184 else {
185 pos = end;
186 return DONE;
187 }
188 }
189
190 /**
191 * Implements CharacterIterator.previous() for String.
192 * @see CharacterIterator#previous
193 */
194 public char previous()
195 {
196 if (pos > begin) {
197 pos--;
198 return text.charAt(pos);
199 }
200 else {
201 return DONE;
202 }
203 }
204
205 /**
206 * Implements CharacterIterator.getBeginIndex() for String.
207 * @see CharacterIterator#getBeginIndex
208 */
209 public int getBeginIndex()
210 {
211 return begin;
212 }
213
214 /**
215 * Implements CharacterIterator.getEndIndex() for String.
216 * @see CharacterIterator#getEndIndex
217 */
218 public int getEndIndex()
219 {
220 return end;
221 }
222
223 /**
224 * Implements CharacterIterator.getIndex() for String.
225 * @see CharacterIterator#getIndex
226 */
227 public int getIndex()
228 {
229 return pos;
230 }
231
232 /**
233 * Compares the equality of two StringCharacterIterator objects.
234 * @param obj the StringCharacterIterator object to be compared with.
235 * @return true if the given obj is the same as this
236 * StringCharacterIterator object; false otherwise.
237 */
238 public boolean equals(Object obj)
239 {
240 if (this == obj)
241 return true;
242 if (!(obj instanceof StringCharacterIterator))
243 return false;
244
245 StringCharacterIterator that = (StringCharacterIterator) obj;
246
247 if (hashCode() != that.hashCode())
248 return false;
249 if (!text.equals(that.text))
250 return false;
251 if (pos != that.pos || begin != that.begin || end != that.end)
252 return false;
253 return true;
254 }
255
256 /**
257 * Computes a hashcode for this iterator.
258 * @return A hash code
259 */
260 public int hashCode()
261 {
262 return text.hashCode() ^ pos ^ begin ^ end;
263 }
264
265 /**
266 * Creates a copy of this iterator.
267 * @return A copy of this
268 */
269 public Object clone()
270 {
271 try {
272 StringCharacterIterator other
273 = (StringCharacterIterator) super.clone();
274 return other;
275 }
276 catch (CloneNotSupportedException e) {
277 throw new InternalError(e);
278 }
279 }
280
281 }