001 /*
002 * Copyright 1996-2005 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.io;
027
028 import java.util.Arrays;
029
030 /**
031 * This class implements a character buffer that can be used as an Writer.
032 * The buffer automatically grows when data is written to the stream. The data
033 * can be retrieved using toCharArray() and toString().
034 * <P>
035 * Note: Invoking close() on this class has no effect, and methods
036 * of this class can be called after the stream has closed
037 * without generating an IOException.
038 *
039 * @author Herb Jellinek
040 * @version 1.31, 05/05/07
041 * @since JDK1.1
042 */
043 public class CharArrayWriter extends Writer {
044 /**
045 * The buffer where data is stored.
046 */
047 protected char buf[];
048
049 /**
050 * The number of chars in the buffer.
051 */
052 protected int count;
053
054 /**
055 * Creates a new CharArrayWriter.
056 */
057 public CharArrayWriter() {
058 this (32);
059 }
060
061 /**
062 * Creates a new CharArrayWriter with the specified initial size.
063 *
064 * @param initialSize an int specifying the initial buffer size.
065 * @exception IllegalArgumentException if initialSize is negative
066 */
067 public CharArrayWriter(int initialSize) {
068 if (initialSize < 0) {
069 throw new IllegalArgumentException(
070 "Negative initial size: " + initialSize);
071 }
072 buf = new char[initialSize];
073 }
074
075 /**
076 * Writes a character to the buffer.
077 */
078 public void write(int c) {
079 synchronized (lock) {
080 int newcount = count + 1;
081 if (newcount > buf.length) {
082 buf = Arrays.copyOf(buf, Math.max(buf.length << 1,
083 newcount));
084 }
085 buf[count] = (char) c;
086 count = newcount;
087 }
088 }
089
090 /**
091 * Writes characters to the buffer.
092 * @param c the data to be written
093 * @param off the start offset in the data
094 * @param len the number of chars that are written
095 */
096 public void write(char c[], int off, int len) {
097 if ((off < 0) || (off > c.length) || (len < 0)
098 || ((off + len) > c.length) || ((off + len) < 0)) {
099 throw new IndexOutOfBoundsException();
100 } else if (len == 0) {
101 return;
102 }
103 synchronized (lock) {
104 int newcount = count + len;
105 if (newcount > buf.length) {
106 buf = Arrays.copyOf(buf, Math.max(buf.length << 1,
107 newcount));
108 }
109 System.arraycopy(c, off, buf, count, len);
110 count = newcount;
111 }
112 }
113
114 /**
115 * Write a portion of a string to the buffer.
116 * @param str String to be written from
117 * @param off Offset from which to start reading characters
118 * @param len Number of characters to be written
119 */
120 public void write(String str, int off, int len) {
121 synchronized (lock) {
122 int newcount = count + len;
123 if (newcount > buf.length) {
124 buf = Arrays.copyOf(buf, Math.max(buf.length << 1,
125 newcount));
126 }
127 str.getChars(off, off + len, buf, count);
128 count = newcount;
129 }
130 }
131
132 /**
133 * Writes the contents of the buffer to another character stream.
134 *
135 * @param out the output stream to write to
136 * @throws IOException If an I/O error occurs.
137 */
138 public void writeTo(Writer out) throws IOException {
139 synchronized (lock) {
140 out.write(buf, 0, count);
141 }
142 }
143
144 /**
145 * Appends the specified character sequence to this writer.
146 *
147 * <p> An invocation of this method of the form <tt>out.append(csq)</tt>
148 * behaves in exactly the same way as the invocation
149 *
150 * <pre>
151 * out.write(csq.toString()) </pre>
152 *
153 * <p> Depending on the specification of <tt>toString</tt> for the
154 * character sequence <tt>csq</tt>, the entire sequence may not be
155 * appended. For instance, invoking the <tt>toString</tt> method of a
156 * character buffer will return a subsequence whose content depends upon
157 * the buffer's position and limit.
158 *
159 * @param csq
160 * The character sequence to append. If <tt>csq</tt> is
161 * <tt>null</tt>, then the four characters <tt>"null"</tt> are
162 * appended to this writer.
163 *
164 * @return This writer
165 *
166 * @since 1.5
167 */
168 public CharArrayWriter append(CharSequence csq) {
169 String s = (csq == null ? "null" : csq.toString());
170 write(s, 0, s.length());
171 return this ;
172 }
173
174 /**
175 * Appends a subsequence of the specified character sequence to this writer.
176 *
177 * <p> An invocation of this method of the form <tt>out.append(csq, start,
178 * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in
179 * exactly the same way as the invocation
180 *
181 * <pre>
182 * out.write(csq.subSequence(start, end).toString()) </pre>
183 *
184 * @param csq
185 * The character sequence from which a subsequence will be
186 * appended. If <tt>csq</tt> is <tt>null</tt>, then characters
187 * will be appended as if <tt>csq</tt> contained the four
188 * characters <tt>"null"</tt>.
189 *
190 * @param start
191 * The index of the first character in the subsequence
192 *
193 * @param end
194 * The index of the character following the last character in the
195 * subsequence
196 *
197 * @return This writer
198 *
199 * @throws IndexOutOfBoundsException
200 * If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>
201 * is greater than <tt>end</tt>, or <tt>end</tt> is greater than
202 * <tt>csq.length()</tt>
203 *
204 * @since 1.5
205 */
206 public CharArrayWriter append(CharSequence csq, int start, int end) {
207 String s = (csq == null ? "null" : csq).subSequence(start, end)
208 .toString();
209 write(s, 0, s.length());
210 return this ;
211 }
212
213 /**
214 * Appends the specified character to this writer.
215 *
216 * <p> An invocation of this method of the form <tt>out.append(c)</tt>
217 * behaves in exactly the same way as the invocation
218 *
219 * <pre>
220 * out.write(c) </pre>
221 *
222 * @param c
223 * The 16-bit character to append
224 *
225 * @return This writer
226 *
227 * @since 1.5
228 */
229 public CharArrayWriter append(char c) {
230 write(c);
231 return this ;
232 }
233
234 /**
235 * Resets the buffer so that you can use it again without
236 * throwing away the already allocated buffer.
237 */
238 public void reset() {
239 count = 0;
240 }
241
242 /**
243 * Returns a copy of the input data.
244 *
245 * @return an array of chars copied from the input data.
246 */
247 public char toCharArray()[] {
248 synchronized (lock) {
249 return Arrays.copyOf(buf, count);
250 }
251 }
252
253 /**
254 * Returns the current size of the buffer.
255 *
256 * @return an int representing the current size of the buffer.
257 */
258 public int size() {
259 return count;
260 }
261
262 /**
263 * Converts input data to a string.
264 * @return the string.
265 */
266 public String toString() {
267 synchronized (lock) {
268 return new String(buf, 0, count);
269 }
270 }
271
272 /**
273 * Flush the stream.
274 */
275 public void flush() {
276 }
277
278 /**
279 * Close the stream. This method does not release the buffer, since its
280 * contents might still be required. Note: Invoking this method in this class
281 * will have no effect.
282 */
283 public void close() {
284 }
285
286 }
|