libjava/javax/imageio/spi/ImageOutputStreamSpi.java

   1 /* ImageOutputStreamSpi.java -- Service provider for image output streams.
   2    Copyright (C) 2004, 2005  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package javax.imageio.spi;
  40
  41 import java.io.File;
  42 import java.io.IOException;
  43
  44 import javax.imageio.stream.ImageOutputStream;
  45
  46 /**
  47  * An abstract superclass for service providers that create
  48  * {@linkplain javax.imageio.stream.ImageOutputStream image output
  49  * streams} for a file, URL, byte array or any other target.
  50  *
  51  * @since 1.4
  52  *
  53  * @author Sascha Brawer (brawer@dandelis.ch)
  54  */
  55 public abstract class ImageOutputStreamSpi
  56   extends IIOServiceProvider
  57 {
  58   /**
  59    * Indicates which kind of output is produced by the streams
  60    * created by {@link #createOutputStreamInstance(Object)}.
  61    */
  62   protected Class outputClass;
  63
  64
  65   /**
  66    * Constructs a service provider for image output streams, given no
  67    * parameters. It is up to the sub-class to set {@link #vendorName},
  68    * {@link #version} and {@link #outputClass} to non-null values.
  69    */
  70   protected ImageOutputStreamSpi()
  71   {
  72   }
  73
  74
  75   /**
  76    * Constructs a service provider for image output streams, given the
  77    * vendor name, a version string and the kind of producable output.
  78    *
  79    * @throws IllegalArgumentException if <code>vendorName</code>
  80    * or <code>version</code> is <code>null</code>.
  81    */
  82   public ImageOutputStreamSpi(String vendorName, String version,
  83                               Class outputClass)
  84   {
  85     super(vendorName, version);
  86     this.outputClass = outputClass;
  87   }
  88
  89
  90   /**
  91    * Determines which kind of output is produced by the streams
  92    * created by {@link #createOutputStreamInstance(Object)}.
  93    */
  94   public Class getOutputClass()
  95   {
  96     return outputClass;
  97   }
  98
  99
 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 }