001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.io;
018
019 import java.io.ByteArrayInputStream;
020 import java.io.IOException;
021 import java.io.InputStream;
022 import java.io.InputStreamReader;
023 import java.io.OutputStream;
024 import java.io.OutputStreamWriter;
025 import java.io.Reader;
026 import java.io.StringReader;
027 import java.io.Writer;
028
029 /**
030 * This class provides static utility methods for buffered
031 * copying between sources (<code>InputStream</code>, <code>Reader</code>,
032 * <code>String</code> and <code>byte[]</code>) and destinations
033 * (<code>OutputStream</code>, <code>Writer</code>, <code>String</code> and
034 * <code>byte[]</code>).
035 * <p>
036 * Unless otherwise noted, these <code>copy</code> methods do <em>not</em>
037 * flush or close the streams. Often doing so would require making non-portable
038 * assumptions about the streams' origin and further use. This means that both
039 * streams' <code>close()</code> methods must be called after copying. if one
040 * omits this step, then the stream resources (sockets, file descriptors) are
041 * released when the associated Stream is garbage-collected. It is not a good
042 * idea to rely on this mechanism. For a good overview of the distinction
043 * between "memory management" and "resource management", see
044 * <a href="http://www.unixreview.com/articles/1998/9804/9804ja/ja.htm">this
045 * UnixReview article</a>.
046 * <p>
047 * For byte-to-char methods, a <code>copy</code> variant allows the encoding
048 * to be selected (otherwise the platform default is used). We would like to
049 * encourage you to always specify the encoding because relying on the platform
050 * default can lead to unexpected results.
051 * <p
052 * We don't provide special variants for the <code>copy</code> methods that
053 * let you specify the buffer size because in modern VMs the impact on speed
054 * seems to be minimal. We're using a default buffer size of 4 KB.
055 * <p>
056 * The <code>copy</code> methods use an internal buffer when copying. It is
057 * therefore advisable <em>not</em> to deliberately wrap the stream arguments
058 * to the <code>copy</code> methods in <code>Buffered*</code> streams. For
059 * example, don't do the following:
060 * <pre>
061 * copy( new BufferedInputStream( in ), new BufferedOutputStream( out ) );
062 * </pre>
063 * The rationale is as follows:
064 * <p>
065 * Imagine that an InputStream's read() is a very expensive operation, which
066 * would usually suggest wrapping in a BufferedInputStream. The
067 * BufferedInputStream works by issuing infrequent
068 * {@link java.io.InputStream#read(byte[] b, int off, int len)} requests on the
069 * underlying InputStream, to fill an internal buffer, from which further
070 * <code>read</code> requests can inexpensively get their data (until the buffer
071 * runs out).
072 * <p>
073 * However, the <code>copy</code> methods do the same thing, keeping an
074 * internal buffer, populated by
075 * {@link InputStream#read(byte[] b, int off, int len)} requests. Having two
076 * buffers (or three if the destination stream is also buffered) is pointless,
077 * and the unnecessary buffer management hurts performance slightly (about 3%,
078 * according to some simple experiments).
079 * <p>
080 * Behold, intrepid explorers; a map of this class:
081 * <pre>
082 * Method Input Output Dependency
083 * ------ ----- ------ -------
084 * 1 copy InputStream OutputStream (primitive)
085 * 2 copy Reader Writer (primitive)
086 *
087 * 3 copy InputStream Writer 2
088 *
089 * 4 copy Reader OutputStream 2
090 *
091 * 5 copy String OutputStream 2
092 * 6 copy String Writer (trivial)
093 *
094 * 7 copy byte[] Writer 3
095 * 8 copy byte[] OutputStream (trivial)
096 * </pre>
097 * <p>
098 * Note that only the first two methods shuffle bytes; the rest use these
099 * two, or (if possible) copy using native Java copy methods. As there are
100 * method variants to specify the encoding, each row may
101 * correspond to up to 2 methods.
102 * <p>
103 * Origin of code: Excalibur.
104 *
105 * @author Peter Donald
106 * @author Jeff Turner
107 * @author Matthew Hawthorne
108 * @version $Id: CopyUtils.java 659817 2008-05-24 13:23:10Z niallp $
109 * @deprecated Use IOUtils. Will be removed in 2.0.
110 * Methods renamed to IOUtils.write() or IOUtils.copy().
111 * Null handling behaviour changed in IOUtils (null data does not
112 * throw NullPointerException).
113 */
114 @Deprecated
115 public class CopyUtils {
116
117 /**
118 * The default size of the buffer.
119 */
120 private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;
121
122 /**
123 * Instances should NOT be constructed in standard programming.
124 */
125 public CopyUtils() { }
126
127 // ----------------------------------------------------------------
128 // byte[] -> OutputStream
129 // ----------------------------------------------------------------
130
131 /**
132 * Copy bytes from a <code>byte[]</code> to an <code>OutputStream</code>.
133 * @param input the byte array to read from
134 * @param output the <code>OutputStream</code> to write to
135 * @throws IOException In case of an I/O problem
136 */
137 public static void copy(byte[] input, OutputStream output)
138 throws IOException {
139 output.write(input);
140 }
141
142 // ----------------------------------------------------------------
143 // byte[] -> Writer
144 // ----------------------------------------------------------------
145
146 /**
147 * Copy and convert bytes from a <code>byte[]</code> to chars on a
148 * <code>Writer</code>.
149 * The platform's default encoding is used for the byte-to-char conversion.
150 * @param input the byte array to read from
151 * @param output the <code>Writer</code> to write to
152 * @throws IOException In case of an I/O problem
153 */
154 public static void copy(byte[] input, Writer output)
155 throws IOException {
156 ByteArrayInputStream in = new ByteArrayInputStream(input);
157 copy(in, output);
158 }
159
160
161 /**
162 * Copy and convert bytes from a <code>byte[]</code> to chars on a
163 * <code>Writer</code>, using the specified encoding.
164 * @param input the byte array to read from
165 * @param output the <code>Writer</code> to write to
166 * @param encoding The name of a supported character encoding. See the
167 * <a href="http://www.iana.org/assignments/character-sets">IANA
168 * Charset Registry</a> for a list of valid encoding types.
169 * @throws IOException In case of an I/O problem
170 */
171 public static void copy(
172 byte[] input,
173 Writer output,
174 String encoding)
175 throws IOException {
176 ByteArrayInputStream in = new ByteArrayInputStream(input);
177 copy(in, output, encoding);
178 }
179
180
181 // ----------------------------------------------------------------
182 // Core copy methods
183 // ----------------------------------------------------------------
184
185 /**
186 * Copy bytes from an <code>InputStream</code> to an
187 * <code>OutputStream</code>.
188 * @param input the <code>InputStream</code> to read from
189 * @param output the <code>OutputStream</code> to write to
190 * @return the number of bytes copied
191 * @throws IOException In case of an I/O problem
192 */
193 public static int copy(
194 InputStream input,
195 OutputStream output)
196 throws IOException {
197 byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
198 int count = 0;
199 int n = 0;
200 while (-1 != (n = input.read(buffer))) {
201 output.write(buffer, 0, n);
202 count += n;
203 }
204 return count;
205 }
206
207 // ----------------------------------------------------------------
208 // Reader -> Writer
209 // ----------------------------------------------------------------
210
211 /**
212 * Copy chars from a <code>Reader</code> to a <code>Writer</code>.
213 * @param input the <code>Reader</code> to read from
214 * @param output the <code>Writer</code> to write to
215 * @return the number of characters copied
216 * @throws IOException In case of an I/O problem
217 */
218 public static int copy(
219 Reader input,
220 Writer output)
221 throws IOException {
222 char[] buffer = new char[DEFAULT_BUFFER_SIZE];
223 int count = 0;
224 int n = 0;
225 while (-1 != (n = input.read(buffer))) {
226 output.write(buffer, 0, n);
227 count += n;
228 }
229 return count;
230 }
231
232 // ----------------------------------------------------------------
233 // InputStream -> Writer
234 // ----------------------------------------------------------------
235
236 /**
237 * Copy and convert bytes from an <code>InputStream</code> to chars on a
238 * <code>Writer</code>.
239 * The platform's default encoding is used for the byte-to-char conversion.
240 * @param input the <code>InputStream</code> to read from
241 * @param output the <code>Writer</code> to write to
242 * @throws IOException In case of an I/O problem
243 */
244 public static void copy(
245 InputStream input,
246 Writer output)
247 throws IOException {
248 InputStreamReader in = new InputStreamReader(input);
249 copy(in, output);
250 }
251
252 /**
253 * Copy and convert bytes from an <code>InputStream</code> to chars on a
254 * <code>Writer</code>, using the specified encoding.
255 * @param input the <code>InputStream</code> to read from
256 * @param output the <code>Writer</code> to write to
257 * @param encoding The name of a supported character encoding. See the
258 * <a href="http://www.iana.org/assignments/character-sets">IANA
259 * Charset Registry</a> for a list of valid encoding types.
260 * @throws IOException In case of an I/O problem
261 */
262 public static void copy(
263 InputStream input,
264 Writer output,
265 String encoding)
266 throws IOException {
267 InputStreamReader in = new InputStreamReader(input, encoding);
268 copy(in, output);
269 }
270
271
272 // ----------------------------------------------------------------
273 // Reader -> OutputStream
274 // ----------------------------------------------------------------
275
276 /**
277 * Serialize chars from a <code>Reader</code> to bytes on an
278 * <code>OutputStream</code>, and flush the <code>OutputStream</code>.
279 * @param input the <code>Reader</code> to read from
280 * @param output the <code>OutputStream</code> to write to
281 * @throws IOException In case of an I/O problem
282 */
283 public static void copy(
284 Reader input,
285 OutputStream output)
286 throws IOException {
287 OutputStreamWriter out = new OutputStreamWriter(output);
288 copy(input, out);
289 // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
290 // have to flush here.
291 out.flush();
292 }
293
294 // ----------------------------------------------------------------
295 // String -> OutputStream
296 // ----------------------------------------------------------------
297
298 /**
299 * Serialize chars from a <code>String</code> to bytes on an
300 * <code>OutputStream</code>, and
301 * flush the <code>OutputStream</code>.
302 * @param input the <code>String</code> to read from
303 * @param output the <code>OutputStream</code> to write to
304 * @throws IOException In case of an I/O problem
305 */
306 public static void copy(
307 String input,
308 OutputStream output)
309 throws IOException {
310 StringReader in = new StringReader(input);
311 OutputStreamWriter out = new OutputStreamWriter(output);
312 copy(in, out);
313 // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
314 // have to flush here.
315 out.flush();
316 }
317
318 // ----------------------------------------------------------------
319 // String -> Writer
320 // ----------------------------------------------------------------
321
322 /**
323 * Copy chars from a <code>String</code> to a <code>Writer</code>.
324 * @param input the <code>String</code> to read from
325 * @param output the <code>Writer</code> to write to
326 * @throws IOException In case of an I/O problem
327 */
328 public static void copy(String input, Writer output)
329 throws IOException {
330 output.write(input);
331 }
332
333 }