http://xmlgraphics.apache.org/batik/batik-awt-util/: Batik AWT utilities (Apache Software Foundation) 
/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
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 */
package org.apache.batik.ext.awt.image.spi;

import java.io.InputStream;
import java.io.StreamCorruptedException;

import org.apache.batik.ext.awt.image.renderable.Filter;
import org.apache.batik.util.ParsedURL;


This type of Image tag registy entry is used for most normal image
file formats.  You are given a markable stream and an opportunity
to check if it is "compatible" if you return true then you will
likely be asked to provide the decoded image next.

See Also:
  • MagicNumberRegistryEntry
Version:$Id: StreamRegistryEntry.java 1733416 2016-03-03 07:07:13Z gadams $
/**
 * This type of Image tag registy entry is used for most normal image
 * file formats.  You are given a markable stream and an opportunity
 * to check if it is "compatible" if you return true then you will
 * likely be asked to provide the decoded image next.
 * @see MagicNumberRegistryEntry
 *
 * @version $Id: StreamRegistryEntry.java 1733416 2016-03-03 07:07:13Z gadams $
 */
public interface StreamRegistryEntry extends RegistryEntry {

    
returns the number of bytes that need to be
supported by mark on the InputStream for this
to check the stream for compatibility.

/**
     * returns the number of bytes that need to be
     * supported by mark on the InputStream for this
     * to check the stream for compatibility.
     */
    int getReadlimit();

    
Check if the Stream references an image that can be handled by
this format handler.  The input stream passed in should be
assumed to support mark and reset.
If this method throws a StreamCorruptedException then the
InputStream will be closed and a new one opened (if possible).
This method should only throw a StreamCorruptedException if it
is unable to restore the state of the InputStream
(i.e. mark/reset fails basically).

/**
     * Check if the Stream references an image that can be handled by
     * this format handler.  The input stream passed in should be
     * assumed to support mark and reset.
     *
     * If this method throws a StreamCorruptedException then the
     * InputStream will be closed and a new one opened (if possible).
     *
     * This method should only throw a StreamCorruptedException if it
     * is unable to restore the state of the InputStream
     * (i.e. mark/reset fails basically).
     */
    boolean isCompatibleStream(InputStream is)
        throws StreamCorruptedException;

    
Decode the Stream into a Filter.  If the stream turns out not to
be of a format this RegistryEntry can handle you should attempt
to reset the stream, then return null.

This should only return a broken link image when the image is
clearly of this format, but is unreadable for some reason.

Params:
  • is – The input stream that contains the image.
  • origURL – The original URL, if any, for documentation
               purposes only.  This may be null.
  • needRawData – If true the image returned should not have
                   any default color correction the file may
                   specify applied.
/**
     * Decode the Stream into a Filter.  If the stream turns out not to
     * be of a format this RegistryEntry can handle you should attempt
     * to reset the stream, then return null.<P>
     *
     * This should only return a broken link image when the image is
     * clearly of this format, but is unreadable for some reason.
     *
     * @param is The input stream that contains the image.
     * @param origURL The original URL, if any, for documentation
     *                purposes only.  This may be null.
     * @param needRawData If true the image returned should not have
     *                    any default color correction the file may
     *                    specify applied.
     */
    Filter handleStream(InputStream is,
                               ParsedURL   origURL,
                               boolean     needRawData);
}