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package javax.mail.internet;

import java.io.*;

An InputStream that is backed by data that can be shared by multiple
readers may implement this interface.  This allows users of such an
InputStream to determine the current position in the InputStream, and
to create new InputStreams representing a subset of the data in the
original InputStream.  The new InputStream will access the same
underlying data as the original, without copying the data. 

Note that implementations of this interface must ensure that the
close method does not close any underlying stream
that might be shared by multiple instances of SharedInputStream
until all shared instances have been closed.
Author:
 Bill Shannon
Since:
JavaMail 1.2/**
 * An InputStream that is backed by data that can be shared by multiple
 * readers may implement this interface.  This allows users of such an
 * InputStream to determine the current position in the InputStream, and
 * to create new InputStreams representing a subset of the data in the
 * original InputStream.  The new InputStream will access the same
 * underlying data as the original, without copying the data. <p>
 *
 * Note that implementations of this interface must ensure that the
 * <code>close</code> method does not close any underlying stream
 * that might be shared by multiple instances of <code>SharedInputStream</code>
 * until all shared instances have been closed.
 *
 * @author  Bill Shannon
 * @since JavaMail 1.2
 */

public interface SharedInputStream {
    
Return the current position in the InputStream, as an
offset from the beginning of the InputStream.
Returns:
	the current position/**
     * Return the current position in the InputStream, as an
     * offset from the beginning of the InputStream.
     *
     * @return	the current position
     */
    public long getPosition();

    
Return a new InputStream representing a subset of the data
from this InputStream, starting at start (inclusive)
up to end (exclusive).  start must be
non-negative.  If end is -1, the new stream ends
at the same place as this stream.  The returned InputStream
will also implement the SharedInputStream interface.
Params:
start – 	the starting position
end – 	the ending position + 1
Returns:
		the new stream/**
     * Return a new InputStream representing a subset of the data
     * from this InputStream, starting at <code>start</code> (inclusive)
     * up to <code>end</code> (exclusive).  <code>start</code> must be
     * non-negative.  If <code>end</code> is -1, the new stream ends
     * at the same place as this stream.  The returned InputStream
     * will also implement the SharedInputStream interface.
     *
     * @param	start	the starting position
     * @param	end	the ending position + 1
     * @return		the new stream
     */
    public InputStream newStream(long start, long end);
}