codat.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *0
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL SUN MICROSYSTEMS OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: Codat.java,v 1.16 2005/12/09 00:53:59 bondolo Exp $
 */

package net.jxta.codat;

import java.io.IOException;

import net.jxta.id.ID;
import net.jxta.id.IDFactory;
import net.jxta.peergroup.PeerGroupID;
import net.jxta.document.Document;

/**
 *  The common container for managing content within JXTA. A Codat consists of:
 *  <ul>
 *      <li>Content data for the Codat in the form of a JXTA 
 *      {@link net.jxta.document.Document}.</li>
 *      <li>A persistent canonical identifier for the Codat in the form of a 
 *      {@link net.jxta.codat.CodatID}.</li>
 *      <li>An optional CodatID for an associated Codat for which this Codat is 
 *      metadata.</li>
 *  </ul>
 *
 * @see net.jxta.codat.CodatID
 * @see net.jxta.document.Document
 **/
public class Codat {
    
    /**
     *  CodatID of this Codat. A persistent canonical identifier for this Codat.
     **/
    private final CodatID id;
    
    /**
     *  CodatID for an associated Codat for which this Codat is metadata. This 
     *  may be the CodatId of another Codat in the same Peer Group or 
     *  <tt>null</tt>.
     **/
    private final CodatID metaId;
    
    /**
     *  Contains the data of this Codat.
     **/
    private final Document doc;
    
    /**
     *  Constructs a Codat instance with a new CodatId given a PeerGroupID and 
     *  a Document.
     *
     *  @param groupID The peer group to which this Codat will belong.
     *  @param about The CodatID of an associated Codat for which this Codat is
     *  metadata or <tt>null</tt> if there is no associated Codat.
     *  @param document Document which contains the content data for this Codat.
     *  @throws IOException if there is an error accessing the document.
     **/
    public Codat( PeerGroupID groupID, CodatID about, Document document) throws IOException {        
        this( IDFactory.newCodatID( groupID, document.getStream() ), about, document );
    }
    
    /**
     *  Constructs a Codat instance for an existing Codat given it's
     *  CodatID and a document.
     *
     *  <p/>This implementation does not verify that the CodatID matches the
     *  provided Document.
     *
     *  @param id CodatId of the new Codat.
     *  @param about CodatID of an associated Codat for which this Codat is metadata.
     *  @param document Document which contains the content data for this Codat.
     **/
    public Codat( CodatID id, CodatID about, Document document) {
        if( null == id ) {
            throw new IllegalArgumentException( "CodatID may not be null.");
        }
        
        if( null == document ) {
            throw new IllegalArgumentException( "Document may not be null.");
        }
        
        this.id = id;
        this.metaId = about;
        this.doc = document;
    }
    
    /**
     *  Returns the CodatID of this Codat.
     *
     *  @return The CodatID of this Codat.
     **/
    public ID getCodatID() {
        return id;
    }
    
    /**
     *  Returns the CodatID of an associated Codat for which this Codat is 
     *  metadata or <tt>null</tt> if there is no associated Codat.
     *
     *  @return CodatID The CodatID of an associated Codat for which this Codat 
     *  is metadata or <tt>null</tt> if there is no associated Codat.
     **/
    public ID getMetaID() {
        return metaId;
    }
    
    /**
     *  Returns a Document containing the data of this Codat.
     *
     *  @return A Document containing the data of this Codat.
     **/
    public Document getDocument() {
        return doc;
    }
}