idformat.java

jxta平台的开发包

/************************************************************************
 *
 * $Id: IDFormat.java,v 1.6 2006/07/20 19:23:35 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:
 *
 * 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,
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 * 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.
 *********************************************************************************/

package net.jxta.impl.id.binaryID;

import java.net.URL;

import java.security.NoSuchAlgorithmException;

import net.jxta.id.IDFactory;

import net.jxta.impl.id.UUID.UUID;
import org.apache.log4j.Logger;
import org.apache.log4j.Level;

/**
 *  The 'BinaryID' format is a general purpose JXTA ID Format. It implements all of
 *  the six standard ID types. It was originally created for the Java 2 SE
 *  reference implementation. The 'BinaryID' format uses randomly generated BinaryIDs
 *  as the mechanism for generating canonical values for the ids it provides.
 *
 * @author Daniel Brookshier <a HREF="mailto:[e-mail]">[e-mail]</a>
 *
 **/
public class IDFormat {
    /** 
     * LOG4J Logger 
     */
    private final static transient Logger LOG = Logger.getLogger(IDFormat.class.getName());    

    /**
     *  This table maps our local private versions of the well known ids to the
     *  globally known version.
     **/
    
    final static Object[] [] wellKnownIDs = {
        { net.jxta.peergroup.PeerGroupID.worldPeerGroupID, net.jxta.impl.id.UUID.IDFormat.worldPeerGroupID },
        { net.jxta.peergroup.PeerGroupID.defaultNetPeerGroupID, net.jxta.impl.id.UUID.IDFormat.defaultNetPeerGroupID }
    };
    
    /**
     * The instantiator for this ID Format which is used by the IDFactory.
     *
     **/
    public static final net.jxta.impl.id.binaryID.Instantiator INSTANTIATOR = new net.jxta.impl.id.binaryID.Instantiator();
    
    /** 
     *  Private Constructor. This class cannot be instantiated.
     **/
    private 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 net.jxta.id.ID translateFromWellKnown( net.jxta.id.ID input ) {
        for( int eachWellKnown = 0; eachWellKnown < wellKnownIDs.length; eachWellKnown++ ) {
            net.jxta.id.ID aWellKnown = (net.jxta.id.ID) wellKnownIDs[eachWellKnown][0];
            if( aWellKnown.equals( input ) )
                return (net.jxta.id.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 net.jxta.id.ID translateToWellKnown( net.jxta.id.ID input ) {
        for( int eachWellKnown = 0; eachWellKnown < wellKnownIDs.length; eachWellKnown++ ) {
            net.jxta.id.ID aLocalEncoding = (net.jxta.id.ID) wellKnownIDs[eachWellKnown][1];
            if( aLocalEncoding.equals( input ) )
                return (net.jxta.id.ID) wellKnownIDs[eachWellKnown][0];
        }
        
        return input;
    }
    
    /**
     * Utility method used to strip only the most significant peer group ID.
     * This prevents us from continiously appending grandparents to each child.
     *
     * <p>
     * This method is used in PipeID and PeerID.
     * </p>
     *
     * @param peerGroupID Peer group ID to pull the child from.
     *
     * @return Child of the peer group.
     *
     */
    public static String childGroup(net.jxta.peergroup.PeerGroupID peerGroupID) {
        String parentStr = (String) peerGroupID.getUniqueValue();
        // Child is the first ID
        int first = parentStr.indexOf('.');
        String child = null;
        if (first != -1){
            child =  parentStr.substring(0,first);
            
        }else{
            child =  parentStr;
        }
        return child;
    }
}