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Java > Open Source Codes > org > apache > commons > httpclient > ChunkedOutputStream


1 /*
2  * $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/ChunkedOutputStream.java,v 1.10.2.1 2004/02/22 18:21:13 olegk Exp $
3  * $Revision: 1.10.2.1 $
4  * $Date: 2004/02/22 18:21:13 $
5  *
6  * ====================================================================
7  *
8  * Copyright 2002-2004 The Apache Software Foundation
9  *
10  * Licensed under the Apache License, Version 2.0 (the "License");
11  * you may not use this file except in compliance with the License.
12  * You may obtain a copy of the License at
13  *
14  * http://www.apache.org/licenses/LICENSE-2.0
15  *
16  * Unless required by applicable law or agreed to in writing, software
17  * distributed under the License is distributed on an "AS IS" BASIS,
18  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19  * See the License for the specific language governing permissions and
20  * limitations under the License.
21  * ====================================================================
22  *
23  * This software consists of voluntary contributions made by many
24  * individuals on behalf of the Apache Software Foundation. For more
25  * information on the Apache Software Foundation, please see
26  * <http://www.apache.org/>.
27  *
28  * [Additional notices, if required by prior licensing conditions]
29  *
30  */
31
32 package org.apache.commons.httpclient;
33
34 import java.io.IOException JavaDoc;
35 import java.io.OutputStream JavaDoc;
36 import org.apache.commons.logging.Log;
37 import org.apache.commons.logging.LogFactory;
38
39 /**
40  * <p>
41  * Wrapper supporting the chunked transfer encoding.
42  * </p>
43  *
44  * @author <a HREF="mailto:remm@apache.org">Remy Maucherat</a>
45  * @author Sean C. Sullivan
46  * @author <a HREF="mailto:dion@apache.org">dIon Gillard</a>
47  * @author <a HREF="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
48  * @author <a HREF="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
49  * @version $Revision: 1.10.2.1 $ $Date: 2004/02/22 18:21:13 $
50  *
51  * @see ChunkedInputStream
52  * @since 2.0
53  *
54  */
55 public class ChunkedOutputStream extends OutputStream JavaDoc {
56
57     // ------------------------------------------------------- Static Variables
58
59     /** <tt>"\r\n"</tt>, as bytes. */
60     private static final byte CRLF[] = new byte[] {(byte) 13, (byte) 10};
61
62     /** End chunk */
63     private static final byte ENDCHUNK[] = CRLF;
64
65     /** 0 */
66     private static final byte ZERO[] = new byte[] {(byte) '0'};
67
68     /** 1 */
69     private static final byte ONE[] = new byte[] {(byte) '1'};
70
71     /** Log object for this class. */
72     private static final Log LOG = LogFactory.getLog(ChunkedOutputStream.class);
73
74     // ----------------------------------------------------- Instance Variables
75
76     /** Has this stream been closed? */
77     private boolean closed = false;
78
79     /** The underlying output stream to which we will write data */
80     private OutputStream JavaDoc stream = null;
81
82     // ----------------------------------------------------------- Constructors
83
84     /**
85      * Construct an output stream wrapping the given stream.
86      * The stream will not use chunking.
87      *
88      * @param stream wrapped output stream. Must be non-null.
89      */
90     public ChunkedOutputStream(OutputStream JavaDoc stream) {
91         if (stream == null) {
92             throw new NullPointerException JavaDoc("stream parameter is null");
93         }
94         this.stream = stream;
95     }
96
97
98     // --------------------------------------------------------- Public Methods
99
100     /**
101      * Writes a <code>String</code> to the client, without a carriage return
102      * line feed (CRLF) character at the end. The platform default encoding is
103      * used!
104      *
105      * @param s the <code>String</code> to send to the client. Must be non-null.
106      * @throws IOException if an input or output exception occurred
107      */
108     public void print(String JavaDoc s) throws IOException JavaDoc {
109         LOG.trace("enter ChunckedOutputStream.print(String)");
110         if (s == null) {
111             s = "null";
112         }
113         write(HttpConstants.getBytes(s));
114     }
115
116     /**
117      * Writes a carriage return-line feed (CRLF) to the client.
118      *
119      * @throws IOException if an input or output exception occurred
120      */
121     public void println() throws IOException JavaDoc {
122         print("\r\n");
123     }
124
125     /**
126      * Writes a <code>String</code> to the client,
127      * followed by a carriage return-line feed (CRLF).
128      *
129      * @param s the </code>String</code> to write to the client
130      * @exception IOException if an input or output exception occurred
131      */
132     public void println(String JavaDoc s) throws IOException JavaDoc {
133         print(s);
134         println();
135     }
136
137     // -------------------------------------------- OutputStream Methods
138
139     /**
140      * Write the specified byte to our output stream.
141      *
142      * @param b The byte to be written
143      * @throws IOException if an input/output error occurs
144      * @throws IllegalStateException if stream already closed
145      */
146     public void write (int b) throws IOException JavaDoc, IllegalStateException JavaDoc {
147         if (closed) {
148             throw new IllegalStateException JavaDoc("Output stream already closed");
149         }
150         //FIXME: If using chunking, the chunks are ONE byte long!
151 stream.write(ONE, 0, ONE.length);
152         stream.write(CRLF, 0, CRLF.length);
153         stream.write(b);
154         stream.write(ENDCHUNK, 0, ENDCHUNK.length);
155         LOG.debug("Writing chunk (length: 1)");
156     }
157
158     /**
159      * Write the specified byte array.
160      *
161      * @param b the byte array to write out
162      * @param off the offset within <code>b</code> to start writing from
163      * @param len the length of data within <code>b</code> to write
164      * @throws IOException when errors occur writing output
165      */
166     public void write (byte[] b, int off, int len) throws IOException JavaDoc {
167         LOG.trace("enter ChunckedOutputStream.write(byte[], int, int)");
168
169         if (closed) {
170             throw new IllegalStateException JavaDoc("Output stream already closed");
171         }
172         byte chunkHeader[] = HttpConstants.getBytes (
173             Integer.toHexString(len) + "\r\n");
174         stream.write(chunkHeader, 0, chunkHeader.length);
175         stream.write(b, off, len);
176         stream.write(ENDCHUNK, 0, ENDCHUNK.length);
177         if (LOG.isDebugEnabled()) {
178             LOG.debug("Writing chunk (length: " + len + ")");
179         }
180     }
181
182     /**
183      * Close this output stream, causing any buffered data to be flushed and
184      * any further output data to throw an IOException. The underlying stream
185      * is not closed!
186      *
187      * @throws IOException if an error occurs closing the stream
188      */
189     public void writeClosingChunk() throws IOException JavaDoc {
190         LOG.trace("enter ChunkedOutputStream.writeClosingChunk()");
191
192         if (!closed) {
193             try {
194                 // Write the final chunk.
195 stream.write(ZERO, 0, ZERO.length);
196                 stream.write(CRLF, 0, CRLF.length);
197                 stream.write(ENDCHUNK, 0, ENDCHUNK.length);
198                 LOG.debug("Writing closing chunk");
199             } catch (IOException JavaDoc e) {
200                 LOG.debug("Unexpected exception caught when closing "
201                     + "output stream", e);
202                 throw e;
203             } finally {
204                 // regardless of what happens, mark the stream as closed.
205 // if there are errors closing it, there's not much we can do
206 // about it
207 closed = true;
208             }
209         }
210     }
211
212     /**
213      * Flushes the underlying stream.
214      * @throws IOException If an IO problem occurs.
215      */
216     public void flush() throws IOException JavaDoc {
217         stream.flush();
218     }
219
220     /**
221      * Close this output stream, causing any buffered data to be flushed and
222      * any further output data to throw an IOException. The underlying stream
223      * is not closed!
224      *
225      * @throws IOException if an error occurs closing the stream
226      */
227     public void close() throws IOException JavaDoc {
228         LOG.trace("enter ChunkedOutputStream.close()");
229         writeClosingChunk();
230         super.close();
231     }
232
233
234 }
235
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