idformat.java

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

/************************************************************************
 *
 * $Id: IDFormat.java,v 1.9 2005/12/08 20:32:51 bondolo Exp $
 *
 * 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:
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 * 1. Redistributions of source code must retain the above copyright
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 * 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",
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ====================================================================
 *
 * 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.
 *********************************************************************************/

package net.jxta.impl.id.UUID;

import org.apache.log4j.Logger;
import org.apache.log4j.Level;

import net.jxta.id.ID;
import net.jxta.id.IDFactory;

/**
 *  A general purpose JXTA ID Format implementing all of the six standard ID
 *  Types. It was originally created for the Java 2 SE reference implementation.
 *  The 'uuid' format uses (IETF version 4) randomly generated UUIDs as the  
 *  mechanism for generating canonical values for the ids it provides.
 *
 *  <p/>For IDs constructed using "seed" varient constructors, the first 16
 *  bytes of the seed are used literally as the UUID value. The value is masked
 *  to make it a valid version 4 IETF varient UUID.
 *
 *  @see net.jxta.id.ID
 *  @see <a href="http://spec.jxta.org/nonav/v1.0/docbook/JXTAProtocols.html#ids" target="_blank">JXTA Protocols Specification : IDs</a>
 *  @see <a href="http://spec.jxta.org/nonav/v1.0/docbook/JXTAProtocols.html#refimpls-ids-jiuft" target="_blank">JXTA Protocols Specification : UUID ID Format</a>
 **/
public class IDFormat {
    
    /**
     *  Log4J Logger
     **/
    private static final transient Logger LOG = Logger.getLogger( IDFormat.class.getName());
    
    /**
     *  number of bytes in the byte array
     **/
    public final static int IdByteArraySize = 64;
    
    /**
     *  The size of a UUID in bytes
     **/
    public final static int uuidSize = 16;
    
    /**
     *  The size of the flags field
     **/
    public final static int flagsSize = 1;
    
    /**
     *  Location of the type field within the flags field
     **/
    public final static int flagsIdTypeOffset = IDFormat.flagsSize - 1;
    
    /**
     *  Type value for Codat
     **/
    public final static byte flagCodatID = 0x01;
    
    /**
     *  Type value for PeerGroup
     **/
    public final static byte flagPeerGroupID = 0x02;
    
    /**
     *  Type value for Peer
     **/
    public final static byte flagPeerID = 0x03;
    
    /**
     *  Type value for Pipe
     **/
    public final static byte flagPipeID = 0x04;
    
    /**
     *  Type value for ModuleClass
     **/
    public final static byte flagModuleClassID = 0x05;
    
    /**
     *  Type value for ModuleSpec
     **/
    public final static byte flagModuleSpecID = 0x06;
    
    /**
     *  Location of ID flags within byte array.
     **/
    public final static int flagsOffset = IDFormat.IdByteArraySize - IDFormat.flagsSize;
    
    /**
     *  Our local version of the world Peer Group ID. We need this for cases
     *  where we have to make ids which are in the world peer group. We only
     *  use this ID for those cases and never return this ID.
     **/
    public static final PeerGroupID worldPeerGroupID = new PeerGroupID(
            new UUID( 0x5961626164616261L, 0x4A78746150325033L ) ); //YabadabaJXTAP2P!
    
    /**
     *  Our local version of the net Peer Group ID. We need this for cases
     *  where we have to make ids which are in the net peer group. We only
     *  use this ID for those cases and never return this ID.
     **/
    public static final PeerGroupID defaultNetPeerGroupID = new PeerGroupID(
            new UUID( 0x5961626164616261L, 0x4E50472050325033L ) ); //YabadabaNPG P2P!
    
    /**
     *  This table maps our local private versions of the well known ids to the
     *  globally known version.
     **/
    private final static Object[] [] wellKnownIDs = {
        { net.jxta.peergroup.PeerGroupID.worldPeerGroupID, worldPeerGroupID },
        { net.jxta.peergroup.PeerGroupID.defaultNetPeerGroupID, defaultNetPeerGroupID }
    };
    
    /**
     * The instantiator for this ID Format which is used by the IDFactory.
     **/
    public static final IDFactory.Instantiator INSTANTIATOR = new Instantiator();
    
    /**
     *  This class cannot be instantiated.
     **/
    protected IDFormat() {
    }
    
    /**
     *  Translate from well known ID to our locally encoded versions.
     *
     *  @param input    the id to be translated.
     *  @return the translated ID or the input ID if no translation was needed.
     **/
    static ID translateFromWellKnown(ID input) {
        for( int eachWellKnown = 0; eachWellKnown < wellKnownIDs.length; eachWellKnown++ ) {
            ID aWellKnown = (ID) wellKnownIDs[eachWellKnown][0];
            
            if( aWellKnown.equals( input ) ) {
                return (ID) wellKnownIDs[eachWellKnown][1];
            }
        }
        
        return input;
    }
    
    /**
     *  Translate from locally encoded versions to the well known versions.
     *
     *  @param input    the id to be translated.
     *  @return the translated ID or the input ID if no translation was needed.
     **/
    static ID translateToWellKnown(ID input) {
        for( int eachWellKnown = 0; eachWellKnown < wellKnownIDs.length; eachWellKnown++ ) {
            ID aLocalEncoding = (ID) wellKnownIDs[eachWellKnown][1];
            
            if( aLocalEncoding.equals( input ) ) {
                return (ID) wellKnownIDs[eachWellKnown][0];
            }
        }
        
        return input;
    }
}