Source Code Cross Referenced for FileCacheImageOutputStream.java in  » 6.0-JDK-Core » image » javax » imageio » stream » Java Source Code / Java DocumentationJava Source Code and Java Documentation

Home
Java Source Code / Java Documentation
1.6.0 JDK Core
2.6.0 JDK Modules
3.6.0 JDK Modules com.sun
4.6.0 JDK Modules com.sun.java
5.6.0 JDK Modules sun
6.6.0 JDK Platform
7.Ajax
8.Apache Harmony Java SE
9.Aspect oriented
10.Authentication Authorization
11.Blogger System
12.Build
13.Byte Code
14.Cache
15.Chart
16.Chat
17.Code Analyzer
18.Collaboration
19.Content Management System
20.Database Client
21.Database DBMS
22.Database JDBC Connection Pool
23.Database ORM
24.Development
25.EJB Server
26.ERP CRM Financial
27.ESB
28.Forum
29.Game
30.GIS
31.Graphic 3D
32.Graphic Library
33.Groupware
34.HTML Parser
35.IDE
36.IDE Eclipse
37.IDE Netbeans
38.Installer
39.Internationalization Localization
40.Inversion of Control
41.Issue Tracking
42.J2EE
43.J2ME
44.JBoss
45.JMS
46.JMX
47.Library
48.Mail Clients
49.Music
50.Net
51.Parser
52.PDF
53.Portal
54.Profiler
55.Project Management
56.Report
57.RSS RDF
58.Rule Engine
59.Science
60.Scripting
61.Search Engine
62.Security
63.Sevlet Container
64.Source Control
65.Swing Library
66.Template Engine
67.Test Coverage
68.Testing
69.UML
70.Web Crawler
71.Web Framework
72.Web Mail
73.Web Server
74.Web Services
75.Web Services apache cxf 2.2.6
76.Web Services AXIS2
77.Wiki Engine
78.Workflow Engines
79.XML
80.XML UI
Java Source Code / Java Documentation » 6.0 JDK Core » image » javax.imageio.stream 
Source Cross Referenced  Class Diagram Java Document (Java Doc) 


001        /*
002         * Copyright 2000-2006 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 javax.imageio.stream;
027
028        import java.io.DataInput;
029        import java.io.File;
030        import java.io.FileNotFoundException;
031        import java.io.IOException;
032        import java.io.OutputStream;
033        import java.io.RandomAccessFile;
034        import com.sun.imageio.stream.StreamCloser;
035
036        /**
037         * An implementation of <code>ImageOutputStream</code> that writes its
038         * output to a regular <code>OutputStream</code>.  A file is used to
039         * cache data until it is flushed to the output stream.
040         *
041         * @version 0.5
042         */
043        public class FileCacheImageOutputStream extends ImageOutputStreamImpl {
044
045            private OutputStream stream;
046
047            private File cacheFile;
048
049            private RandomAccessFile cache;
050
051            // Pos after last (rightmost) byte written
052            private long maxStreamPos = 0L;
053
054            /**
055             * Constructs a <code>FileCacheImageOutputStream</code> that will write
056             * to a given <code>outputStream</code>.
057             *
058             * <p> A temporary file is used as a cache.  If
059             * <code>cacheDir</code>is non-<code>null</code> and is a
060             * directory, the file will be created there.  If it is
061             * <code>null</code>, the system-dependent default temporary-file
062             * directory will be used (see the documentation for
063             * <code>File.createTempFile</code> for details).
064             *
065             * @param stream an <code>OutputStream</code> to write to.
066             * @param cacheDir a <code>File</code> indicating where the 
067             * cache file should be created, or <code>null</code> to use the
068             * system directory.
069             *
070             * @exception IllegalArgumentException if <code>stream</code>
071             * is <code>null</code>.
072             * @exception IllegalArgumentException if <code>cacheDir</code> is
073             * non-<code>null</code> but is not a directory.
074             * @exception IOException if a cache file cannot be created.
075             */
076            public FileCacheImageOutputStream(OutputStream stream, File cacheDir)
077                    throws IOException {
078                if (stream == null) {
079                    throw new IllegalArgumentException("stream == null!");
080                }
081                if ((cacheDir != null) && !(cacheDir.isDirectory())) {
082                    throw new IllegalArgumentException("Not a directory!");
083                }
084                this .stream = stream;
085                this .cacheFile = File.createTempFile("imageio", ".tmp",
086                        cacheDir);
087                this .cache = new RandomAccessFile(cacheFile, "rw");
088                StreamCloser.addToQueue(this );
089            }
090
091            public int read() throws IOException {
092                checkClosed();
093                bitOffset = 0;
094                int val = cache.read();
095                if (val != -1) {
096                    ++streamPos;
097                }
098                return val;
099            }
100
101            public int read(byte[] b, int off, int len) throws IOException {
102                checkClosed();
103
104                if (b == null) {
105                    throw new NullPointerException("b == null!");
106                }
107                if (off < 0 || len < 0 || off + len > b.length || off + len < 0) {
108                    throw new IndexOutOfBoundsException(
109                            "off < 0 || len < 0 || off+len > b.length || off+len < 0!");
110                }
111
112                bitOffset = 0;
113
114                if (len == 0) {
115                    return 0;
116                }
117
118                int nbytes = cache.read(b, off, len);
119                if (nbytes != -1) {
120                    streamPos += nbytes;
121                }
122                return nbytes;
123            }
124
125            public void write(int b) throws IOException {
126                flushBits(); // this will call checkClosed() for us
127                cache.write(b);
128                ++streamPos;
129                maxStreamPos = Math.max(maxStreamPos, streamPos);
130            }
131
132            public void write(byte[] b, int off, int len) throws IOException {
133                flushBits(); // this will call checkClosed() for us
134                cache.write(b, off, len);
135                streamPos += len;
136                maxStreamPos = Math.max(maxStreamPos, streamPos);
137            }
138
139            public long length() {
140                try {
141                    checkClosed();
142                    return cache.length();
143                } catch (IOException e) {
144                    return -1L;
145                }
146            }
147
148            /**
149             * Sets the current stream position and resets the bit offset to
150             * 0.  It is legal to seek past the end of the file; an
151             * <code>EOFException</code> will be thrown only if a read is
152             * performed.  The file length will not be increased until a write
153             * is performed.
154             *
155             * @exception IndexOutOfBoundsException if <code>pos</code> is smaller
156             * than the flushed position.
157             * @exception IOException if any other I/O error occurs.
158             */
159            public void seek(long pos) throws IOException {
160                checkClosed();
161
162                if (pos < flushedPos) {
163                    throw new IndexOutOfBoundsException();
164                }
165
166                cache.seek(pos);
167                this .streamPos = cache.getFilePointer();
168                maxStreamPos = Math.max(maxStreamPos, streamPos);
169                this .bitOffset = 0;
170            }
171
172            /**
173             * Returns <code>true</code> since this
174             * <code>ImageOutputStream</code> caches data in order to allow
175             * seeking backwards.
176             *
177             * @return <code>true</code>.
178             *
179             * @see #isCachedMemory
180             * @see #isCachedFile
181             */
182            public boolean isCached() {
183                return true;
184            }
185
186            /**
187             * Returns <code>true</code> since this
188             * <code>ImageOutputStream</code> maintains a file cache.
189             *
190             * @return <code>true</code>.
191             *
192             * @see #isCached
193             * @see #isCachedMemory
194             */
195            public boolean isCachedFile() {
196                return true;
197            }
198
199            /**
200             * Returns <code>false</code> since this
201             * <code>ImageOutputStream</code> does not maintain a main memory
202             * cache.
203             *
204             * @return <code>false</code>.
205             *
206             * @see #isCached
207             * @see #isCachedFile
208             */
209            public boolean isCachedMemory() {
210                return false;
211            }
212
213            /**
214             * Closes this <code>FileCacheImageOututStream</code>.  All
215             * pending data is flushed to the output, and the cache file
216             * is closed and removed.  The destination <code>OutputStream</code>
217             * is not closed.
218             *
219             * @exception IOException if an error occurs.
220             */
221            public void close() throws IOException {
222                maxStreamPos = cache.length();
223
224                seek(maxStreamPos);
225                flushBefore(maxStreamPos);
226                super .close();
227                cache.close();
228                cache = null;
229                cacheFile.delete();
230                cacheFile = null;
231                stream.flush();
232                stream = null;
233                StreamCloser.removeFromQueue(this );
234            }
235
236            public void flushBefore(long pos) throws IOException {
237                long oFlushedPos = flushedPos;
238                super .flushBefore(pos); // this will call checkClosed() for us
239
240                long flushBytes = flushedPos - oFlushedPos;
241                if (flushBytes > 0) {
242                    int bufLen = 512;
243                    byte[] buf = new byte[bufLen];
244                    cache.seek(oFlushedPos);
245                    while (flushBytes > 0) {
246                        int len = (int) Math.min(flushBytes, bufLen);
247                        cache.readFully(buf, 0, len);
248                        stream.write(buf, 0, len);
249                        flushBytes -= len;
250                    }
251                    stream.flush();
252                }
253            }
254        }
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.