001 /* ImageOutputStreamSpi.java -- Service provider for image output streams.
002 Copyright (C) 2004, 2005 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package javax.imageio.spi;
040
041 import java.io.File;
042 import java.io.IOException;
043
044 import javax.imageio.stream.ImageOutputStream;
045
046 /**
047 * An abstract superclass for service providers that create
048 * {@linkplain javax.imageio.stream.ImageOutputStream image output
049 * streams} for a file, URL, byte array or any other target.
050 *
051 * @since 1.4
052 *
053 * @author Sascha Brawer (brawer@dandelis.ch)
054 */
055 public abstract class ImageOutputStreamSpi
056 extends IIOServiceProvider
057 {
058 /**
059 * Indicates which kind of output is produced by the streams
060 * created by {@link #createOutputStreamInstance(Object)}.
061 */
062 protected Class<?> outputClass;
063
064
065 /**
066 * Constructs a service provider for image output streams, given no
067 * parameters. It is up to the sub-class to set {@link #vendorName},
068 * {@link #version} and {@link #outputClass} to non-null values.
069 */
070 protected ImageOutputStreamSpi()
071 {
072 }
073
074
075 /**
076 * Constructs a service provider for image output streams, given the
077 * vendor name, a version string and the kind of producable output.
078 *
079 * @throws IllegalArgumentException if <code>vendorName</code>
080 * or <code>version</code> is <code>null</code>.
081 */
082 public ImageOutputStreamSpi(String vendorName, String version,
083 Class<?> outputClass)
084 {
085 super(vendorName, version);
086 this.outputClass = outputClass;
087 }
088
089
090 /**
091 * Determines which kind of output is produced by the streams
092 * created by {@link #createOutputStreamInstance(Object)}.
093 */
094 public Class<?> getOutputClass()
095 {
096 return outputClass;
097 }
098
099
100 /**
101 * Determines whether <code>ImageOutputStreams</code> created
102 * by this service provider benefit from using a cache file.
103 *
104 * <p>The default behavior is to return <code>false</code>.
105 *
106 * @return <code>true</code> if the created streams are faster or
107 * need less memory when a cache file is being used;
108 * <code>false</code> if no positive effect results from the cache
109 * file.
110 */
111 public boolean canUseCacheFile()
112 {
113 return false;
114 }
115
116
117 /**
118 * Determines whether <code>ImageOutputStreams</code> created
119 * by this service provider require the use of a cache file.
120 *
121 * <p>The default behavior is to return <code>false</code>.
122 *
123 * @return <code>true</code> if the created streams can only work
124 * when a cache file is being used; <code>false</code> if no cache
125 * file is needed.
126 */
127 public boolean needsCacheFile()
128 {
129 return false;
130 }
131
132
133 public abstract ImageOutputStream createOutputStreamInstance(
134 Object output, boolean useCache, File cacheDir)
135 throws IOException;
136
137
138 public ImageOutputStream createOutputStreamInstance(Object output)
139 throws IOException
140 {
141 return createOutputStreamInstance(output, canUseCacheFile(), null);
142 }
143 }