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 */
017package org.apache.commons.io;
018
019import java.io.ByteArrayInputStream;
020import java.io.IOException;
021import java.io.InputStream;
022import java.io.InputStreamReader;
023import java.io.OutputStream;
024import java.io.OutputStreamWriter;
025import java.io.Reader;
026import java.io.StringReader;
027import java.io.Writer;
028import java.nio.charset.Charset;
029
030/**
031 * This class provides static utility methods for buffered
032 * copying between sources (<code>InputStream</code>, <code>Reader</code>,
033 * <code>String</code> and <code>byte[]</code>) and destinations
034 * (<code>OutputStream</code>, <code>Writer</code>, <code>String</code> and
035 * <code>byte[]</code>).
036 * <p>
037 * Unless otherwise noted, these <code>copy</code> methods do <em>not</em>
038 * flush or close the streams. Often doing so would require making non-portable
039 * assumptions about the streams' origin and further use. This means that both
040 * streams' <code>close()</code> methods must be called after copying. if one
041 * omits this step, then the stream resources (sockets, file descriptors) are
042 * released when the associated Stream is garbage-collected. It is not a good
043 * idea to rely on this mechanism. For a good overview of the distinction
044 * between "memory management" and "resource management", see
045 * <a href="http://www.unixreview.com/articles/1998/9804/9804ja/ja.htm">this
046 * UnixReview article</a>.
047 * <p>
048 * For byte-to-char methods, a <code>copy</code> variant allows the encoding
049 * to be selected (otherwise the platform default is used). We would like to
050 * encourage you to always specify the encoding because relying on the platform
051 * default can lead to unexpected results.
052 * <p>
053 * We don't provide special variants for the <code>copy</code> methods that
054 * let you specify the buffer size because in modern VMs the impact on speed
055 * seems to be minimal. We're using a default buffer size of 4 KB.
056 * <p>
057 * The <code>copy</code> methods use an internal buffer when copying. It is
058 * therefore advisable <em>not</em> to deliberately wrap the stream arguments
059 * to the <code>copy</code> methods in <code>Buffered*</code> streams. For
060 * example, don't do the following:
061 * <pre>
062 *  copy( new BufferedInputStream( in ), new BufferedOutputStream( out ) );
063 *  </pre>
064 * The rationale is as follows:
065 * <p>
066 * Imagine that an InputStream's read() is a very expensive operation, which
067 * would usually suggest wrapping in a BufferedInputStream. The
068 * BufferedInputStream works by issuing infrequent
069 * {@link java.io.InputStream#read(byte[] b, int off, int len)} requests on the
070 * underlying InputStream, to fill an internal buffer, from which further
071 * <code>read</code> requests can inexpensively get their data (until the buffer
072 * runs out).
073 * <p>
074 * However, the <code>copy</code> methods do the same thing, keeping an
075 * internal buffer, populated by
076 * {@link InputStream#read(byte[] b, int off, int len)} requests. Having two
077 * buffers (or three if the destination stream is also buffered) is pointless,
078 * and the unnecessary buffer management hurts performance slightly (about 3%,
079 * according to some simple experiments).
080 * <p>
081 * Behold, intrepid explorers; a map of this class:
082 * <pre>
083 *       Method      Input               Output          Dependency
084 *       ------      -----               ------          -------
085 * 1     copy        InputStream         OutputStream    (primitive)
086 * 2     copy        Reader              Writer          (primitive)
087 *
088 * 3     copy        InputStream         Writer          2
089 *
090 * 4     copy        Reader              OutputStream    2
091 *
092 * 5     copy        String              OutputStream    2
093 * 6     copy        String              Writer          (trivial)
094 *
095 * 7     copy        byte[]              Writer          3
096 * 8     copy        byte[]              OutputStream    (trivial)
097 * </pre>
098 * <p>
099 * Note that only the first two methods shuffle bytes; the rest use these
100 * two, or (if possible) copy using native Java copy methods. As there are
101 * method variants to specify the encoding, each row may
102 * correspond to up to 2 methods.
103 * <p>
104 * Origin of code: Excalibur.
105 *
106 * @version $Id: CopyUtils.java 1680650 2015-05-20 18:36:40Z britter $
107 * @deprecated Use IOUtils. Will be removed in 2.0.
108 *  Methods renamed to IOUtils.write() or IOUtils.copy().
109 *  Null handling behaviour changed in IOUtils (null data does not
110 *  throw NullPointerException).
111 */
112@Deprecated
113public class CopyUtils {
114
115    /**
116     * The default size of the buffer.
117     */
118    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;
119
120    /**
121     * Instances should NOT be constructed in standard programming.
122     */
123    public CopyUtils() { }
124
125    // ----------------------------------------------------------------
126    // byte[] -> OutputStream
127    // ----------------------------------------------------------------
128
129    /**
130     * Copy bytes from a <code>byte[]</code> to an <code>OutputStream</code>.
131     * @param input the byte array to read from
132     * @param output the <code>OutputStream</code> to write to
133     * @throws IOException In case of an I/O problem
134     */
135    public static void copy(final byte[] input, final OutputStream output)
136            throws IOException {
137        output.write(input);
138    }
139
140    // ----------------------------------------------------------------
141    // byte[] -> Writer
142    // ----------------------------------------------------------------
143
144    /**
145     * Copy and convert bytes from a <code>byte[]</code> to chars on a
146     * <code>Writer</code>.
147     * The platform's default encoding is used for the byte-to-char conversion.
148     * @param input the byte array to read from
149     * @param output the <code>Writer</code> to write to
150     * @throws IOException In case of an I/O problem
151     * @deprecated 2.5 use {@link #copy(byte[], Writer, String)} instead
152     */
153    @Deprecated
154    public static void copy(final byte[] input, final Writer output)
155            throws IOException {
156        final 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            final byte[] input,
173            final Writer output,
174            final String encoding)
175                throws IOException {
176        final 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            final InputStream input,
195            final OutputStream output)
196                throws IOException {
197        final 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            final Reader input,
220            final Writer output)
221                throws IOException {
222        final 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     * @deprecated 2.5 use {@link #copy(InputStream, Writer, String)} instead
244     */
245    @Deprecated
246    public static void copy(
247            final InputStream input,
248            final Writer output)
249                throws IOException {
250        // make explicit the dependency on the default encoding
251        final InputStreamReader in = new InputStreamReader(input, Charset.defaultCharset());
252        copy(in, output);
253    }
254
255    /**
256     * Copy and convert bytes from an <code>InputStream</code> to chars on a
257     * <code>Writer</code>, using the specified encoding.
258     * @param input the <code>InputStream</code> to read from
259     * @param output the <code>Writer</code> to write to
260     * @param encoding The name of a supported character encoding. See the
261     * <a href="http://www.iana.org/assignments/character-sets">IANA
262     * Charset Registry</a> for a list of valid encoding types.
263     * @throws IOException In case of an I/O problem
264     */
265    public static void copy(
266            final InputStream input,
267            final Writer output,
268            final String encoding)
269                throws IOException {
270        final InputStreamReader in = new InputStreamReader(input, encoding);
271        copy(in, output);
272    }
273
274
275    // ----------------------------------------------------------------
276    // Reader -> OutputStream
277    // ----------------------------------------------------------------
278
279    /**
280     * Serialize chars from a <code>Reader</code> to bytes on an
281     * <code>OutputStream</code>, and flush the <code>OutputStream</code>.
282     * Uses the default platform encoding.
283     * @param input the <code>Reader</code> to read from
284     * @param output the <code>OutputStream</code> to write to
285     * @throws IOException In case of an I/O problem
286     * @deprecated 2.5 use {@link #copy(Reader, OutputStream, String)} instead
287     */
288    @Deprecated
289    public static void copy(
290            final Reader input,
291            final OutputStream output)
292                throws IOException {
293        // make explicit the dependency on the default encoding
294        final OutputStreamWriter out = new OutputStreamWriter(output, Charset.defaultCharset());
295        copy(input, out);
296        // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
297        // have to flush here.
298        out.flush();
299    }
300
301    /**
302     * Serialize chars from a <code>Reader</code> to bytes on an
303     * <code>OutputStream</code>, and flush the <code>OutputStream</code>.
304     * @param input the <code>Reader</code> to read from
305     * @param output the <code>OutputStream</code> to write to
306     * @param encoding The name of a supported character encoding. See the
307     * <a href="http://www.iana.org/assignments/character-sets">IANA
308     * Charset Registry</a> for a list of valid encoding types.
309     * @throws IOException In case of an I/O problem
310     * @since 2.5
311     */
312    public static void copy(
313            final Reader input,
314            final OutputStream output,
315            final String encoding)
316                throws IOException {
317        final OutputStreamWriter out = new OutputStreamWriter(output, encoding);
318        copy(input, out);
319        // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
320        // have to flush here.
321        out.flush();
322    }
323
324    // ----------------------------------------------------------------
325    // String -> OutputStream
326    // ----------------------------------------------------------------
327
328    /**
329     * Serialize chars from a <code>String</code> to bytes on an
330     * <code>OutputStream</code>, and
331     * flush the <code>OutputStream</code>.
332     * Uses the platform default encoding.
333     * @param input the <code>String</code> to read from
334     * @param output the <code>OutputStream</code> to write to
335     * @throws IOException In case of an I/O problem
336     * @deprecated 2.5 use {@link #copy(String, OutputStream, String)} instead
337     */
338    @Deprecated
339    public static void copy(
340            final String input,
341            final OutputStream output)
342                throws IOException {
343        final StringReader in = new StringReader(input);
344        // make explicit the dependency on the default encoding
345        final OutputStreamWriter out = new OutputStreamWriter(output, Charset.defaultCharset());
346        copy(in, out);
347        // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
348        // have to flush here.
349        out.flush();
350    }
351
352    /**
353     * Serialize chars from a <code>String</code> to bytes on an
354     * <code>OutputStream</code>, and
355     * flush the <code>OutputStream</code>.
356     * @param input the <code>String</code> to read from
357     * @param output the <code>OutputStream</code> to write to
358     * @param encoding The name of a supported character encoding. See the
359     * <a href="http://www.iana.org/assignments/character-sets">IANA
360     * Charset Registry</a> for a list of valid encoding types.
361     * @throws IOException In case of an I/O problem
362     * @since 2.5
363     */
364    public static void copy(
365            final String input,
366            final OutputStream output,
367            final String encoding)
368                throws IOException {
369        final StringReader in = new StringReader(input);
370        final OutputStreamWriter out = new OutputStreamWriter(output, encoding);
371        copy(in, out);
372        // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
373        // have to flush here.
374        out.flush();
375    }
376
377    // ----------------------------------------------------------------
378    // String -> Writer
379    // ----------------------------------------------------------------
380
381    /**
382     * Copy chars from a <code>String</code> to a <code>Writer</code>.
383     * @param input the <code>String</code> to read from
384     * @param output the <code>Writer</code> to write to
385     * @throws IOException In case of an I/O problem
386     */
387    public static void copy(final String input, final Writer output)
388                throws IOException {
389        output.write(input);
390    }
391
392}