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 437680 2006-08-28 11:57:00Z scolebourne $
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: public class CopyUtils {
115:
116: /**
117: * The default size of the buffer.
118: */
119: private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;
120:
121: /**
122: * Instances should NOT be constructed in standard programming.
123: */
124: public CopyUtils() {
125: }
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: * Copy and convert bytes from a <code>byte[]</code> to chars on a
162: * <code>Writer</code>, using the specified encoding.
163: * @param input the byte array to read from
164: * @param output the <code>Writer</code> to write to
165: * @param encoding The name of a supported character encoding. See the
166: * <a href="http://www.iana.org/assignments/character-sets">IANA
167: * Charset Registry</a> for a list of valid encoding types.
168: * @throws IOException In case of an I/O problem
169: */
170: public static void copy(byte[] input, Writer output, String encoding)
171: throws IOException {
172: ByteArrayInputStream in = new ByteArrayInputStream(input);
173: copy(in, output, encoding);
174: }
175:
176: // ----------------------------------------------------------------
177: // Core copy methods
178: // ----------------------------------------------------------------
179:
180: /**
181: * Copy bytes from an <code>InputStream</code> to an
182: * <code>OutputStream</code>.
183: * @param input the <code>InputStream</code> to read from
184: * @param output the <code>OutputStream</code> to write to
185: * @return the number of bytes copied
186: * @throws IOException In case of an I/O problem
187: */
188: public static int copy(InputStream input, OutputStream output)
189: throws IOException {
190: byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
191: int count = 0;
192: int n = 0;
193: while (-1 != (n = input.read(buffer))) {
194: output.write(buffer, 0, n);
195: count += n;
196: }
197: return count;
198: }
199:
200: // ----------------------------------------------------------------
201: // Reader -> Writer
202: // ----------------------------------------------------------------
203:
204: /**
205: * Copy chars from a <code>Reader</code> to a <code>Writer</code>.
206: * @param input the <code>Reader</code> to read from
207: * @param output the <code>Writer</code> to write to
208: * @return the number of characters copied
209: * @throws IOException In case of an I/O problem
210: */
211: public static int copy(Reader input, Writer output)
212: throws IOException {
213: char[] buffer = new char[DEFAULT_BUFFER_SIZE];
214: int count = 0;
215: int n = 0;
216: while (-1 != (n = input.read(buffer))) {
217: output.write(buffer, 0, n);
218: count += n;
219: }
220: return count;
221: }
222:
223: // ----------------------------------------------------------------
224: // InputStream -> Writer
225: // ----------------------------------------------------------------
226:
227: /**
228: * Copy and convert bytes from an <code>InputStream</code> to chars on a
229: * <code>Writer</code>.
230: * The platform's default encoding is used for the byte-to-char conversion.
231: * @param input the <code>InputStream</code> to read from
232: * @param output the <code>Writer</code> to write to
233: * @throws IOException In case of an I/O problem
234: */
235: public static void copy(InputStream input, Writer output)
236: throws IOException {
237: InputStreamReader in = new InputStreamReader(input);
238: copy(in, output);
239: }
240:
241: /**
242: * Copy and convert bytes from an <code>InputStream</code> to chars on a
243: * <code>Writer</code>, using the specified encoding.
244: * @param input the <code>InputStream</code> to read from
245: * @param output the <code>Writer</code> to write to
246: * @param encoding The name of a supported character encoding. See the
247: * <a href="http://www.iana.org/assignments/character-sets">IANA
248: * Charset Registry</a> for a list of valid encoding types.
249: * @throws IOException In case of an I/O problem
250: */
251: public static void copy(InputStream input, Writer output,
252: String encoding) throws IOException {
253: InputStreamReader in = new InputStreamReader(input, encoding);
254: copy(in, output);
255: }
256:
257: // ----------------------------------------------------------------
258: // Reader -> OutputStream
259: // ----------------------------------------------------------------
260:
261: /**
262: * Serialize chars from a <code>Reader</code> to bytes on an
263: * <code>OutputStream</code>, and flush the <code>OutputStream</code>.
264: * @param input the <code>Reader</code> to read from
265: * @param output the <code>OutputStream</code> to write to
266: * @throws IOException In case of an I/O problem
267: */
268: public static void copy(Reader input, OutputStream output)
269: throws IOException {
270: OutputStreamWriter out = new OutputStreamWriter(output);
271: copy(input, out);
272: // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
273: // have to flush here.
274: out.flush();
275: }
276:
277: // ----------------------------------------------------------------
278: // String -> OutputStream
279: // ----------------------------------------------------------------
280:
281: /**
282: * Serialize chars from a <code>String</code> to bytes on an
283: * <code>OutputStream</code>, and
284: * flush the <code>OutputStream</code>.
285: * @param input the <code>String</code> to read from
286: * @param output the <code>OutputStream</code> to write to
287: * @throws IOException In case of an I/O problem
288: */
289: public static void copy(String input, OutputStream output)
290: throws IOException {
291: StringReader in = new StringReader(input);
292: OutputStreamWriter out = new OutputStreamWriter(output);
293: copy(in, out);
294: // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
295: // have to flush here.
296: out.flush();
297: }
298:
299: // ----------------------------------------------------------------
300: // String -> Writer
301: // ----------------------------------------------------------------
302:
303: /**
304: * Copy chars from a <code>String</code> to a <code>Writer</code>.
305: * @param input the <code>String</code> to read from
306: * @param output the <code>Writer</code> to write to
307: * @throws IOException In case of an I/O problem
308: */
309: public static void copy(String input, Writer output)
310: throws IOException {
311: output.write(input);
312: }
313:
314: }
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