001    /*
002     * JBoss, Home of Professional Open Source.
003     * Copyright 2008, Red Hat Middleware LLC, and individual contributors
004     * as indicated by the @author tags. See the copyright.txt file in the
005     * distribution for a full listing of individual contributors. 
006     *
007     * This is free software; you can redistribute it and/or modify it
008     * under the terms of the GNU Lesser General Public License as
009     * published by the Free Software Foundation; either version 2.1 of
010     * the License, or (at your option) any later version.
011     *
012     * This software is distributed in the hope that it will be useful,
013     * but WITHOUT ANY WARRANTY; without even the implied warranty of
014     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015     * Lesser General Public License for more details.
016     *
017     * You should have received a copy of the GNU Lesser General Public
018     * License along with this software; if not, write to the Free
019     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
020     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
021     */
022    package org.jboss.dna.graph.properties;
023    
024    import java.io.InputStream;
025    import java.io.Serializable;
026    import java.security.MessageDigest;
027    import net.jcip.annotations.Immutable;
028    
029    /**
030     * Value holder for binary data. Binary instances are not mutable.
031     * 
032     * @author Randall Hauch
033     */
034    @Immutable
035    public interface Binary extends Comparable<Binary>, Serializable {
036    
037        /**
038         * Get the length of this binary data.
039         * 
040         * @return the number of bytes in this binary data
041         * @see #acquire()
042         */
043        public long getSize();
044    
045        /**
046         * Get the SHA-1 hash of the contents. This hash can be used to determine whether two Binary instances contain the same
047         * content.
048         * <p>
049         * Repeatedly calling this method should generally be efficient, as it most implementations will compute the hash only once.
050         * </p>
051         * 
052         * @return the hash of the contents as a byte array, or an empty array if the hash could not be computed.
053         * @see #acquire()
054         * @see MessageDigest#digest(byte[])
055         * @see MessageDigest#getInstance(String)
056         */
057        public byte[] getHash();
058    
059        /**
060         * Get the contents of this data as a stream.
061         * 
062         * @return the stream to this data's contents
063         * @see #acquire()
064         */
065        public InputStream getStream();
066    
067        /**
068         * Get the contents of this data as a byte array.
069         * 
070         * @return the data as an array
071         * @see #acquire()
072         */
073        public byte[] getBytes();
074    
075        /**
076         * Acquire any resources for this data. This method must be called before any other method on this object.
077         * 
078         * @see #release()
079         */
080        public void acquire();
081    
082        /**
083         * Release any acquired resources. This method must be called after a client is finished with this value.
084         * 
085         * @see #acquire()
086         */
087        public void release();
088    
089    }