ImageOutputStreamSpi.java

/* ImageOutputStreamSpi.java -- Service provider for image output streams.
   Copyright (C) 2004, 2005  Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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this exception to your version of the library, but you are not
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package javax.imageio.spi;

import java.io.File;
import java.io.IOException;

import javax.imageio.stream.ImageOutputStream;

/**
 * An abstract superclass for service providers that create
 * {@linkplain javax.imageio.stream.ImageOutputStream image output
 * streams} for a file, URL, byte array or any other target.
 *
 * @since 1.4
 *
 * @author Sascha Brawer (brawer@dandelis.ch)
 */
public abstract class ImageOutputStreamSpi
  extends IIOServiceProvider
{
  /**
   * Indicates which kind of output is produced by the streams
   * created by {@link #createOutputStreamInstance(Object)}.
   */
  protected Class<?> outputClass;


  /**
   * Constructs a service provider for image output streams, given no
   * parameters. It is up to the sub-class to set {@link #vendorName},
   * {@link #version} and {@link #outputClass} to non-null values.
   */
  protected ImageOutputStreamSpi()
  {
  }


  /**
   * Constructs a service provider for image output streams, given the
   * vendor name, a version string and the kind of producable output.
   *
   * @throws IllegalArgumentException if <code>vendorName</code>
   * or <code>version</code> is <code>null</code>.
   */
  public ImageOutputStreamSpi(String vendorName, String version,
                              Class<?> outputClass)
  {
    super(vendorName, version);
    this.outputClass = outputClass;
  }


  /**
   * Determines which kind of output is produced by the streams
   * created by {@link #createOutputStreamInstance(Object)}.
   */
  public Class<?> getOutputClass()
  {
    return outputClass;
  }


  /**
   * Determines whether <code>ImageOutputStreams</code> created
   * by this service provider benefit from using a cache file.
   *
   * <p>The default behavior is to return <code>false</code>.
   *
   * @return <code>true</code> if the created streams are faster or
   * need less memory when a cache file is being used;
   * <code>false</code> if no positive effect results from the cache
   * file.
   */
  public boolean canUseCacheFile()
  {
    return false;
  }


  /**
   * Determines whether <code>ImageOutputStreams</code> created
   * by this service provider require the use of a cache file.
   *
   * <p>The default behavior is to return <code>false</code>.
   *
   * @return <code>true</code> if the created streams can only work
   * when a cache file is being used; <code>false</code> if no cache
   * file is needed.
   */
  public boolean needsCacheFile()
  {
    return false;
  }


  public abstract ImageOutputStream createOutputStreamInstance(
    Object output, boolean useCache, File cacheDir)
    throws IOException;


  public ImageOutputStream createOutputStreamInstance(Object output)
    throws IOException
  {
    return createOutputStreamInstance(output, canUseCacheFile(), null);
  }
}