srdimessage.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:
 *
 *  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: SrdiMessage.java,v 1.15 2005/09/01 18:00:31 bondolo Exp $
 */
package net.jxta.protocol;


import java.util.Collection;
import java.util.ArrayList;
import java.util.HashSet;

import net.jxta.document.Document;
import net.jxta.document.MimeMediaType;
import net.jxta.peer.PeerID;


/**
 *  A generic message that can be used by services to push shared resources to
 *  other peers on the network
 */
public abstract class SrdiMessage {
    private final Collection entries = new HashSet();

    private PeerID peerid = null;
    private String primaryKey = null;
    
    /**
     *  Time to live of SrdiMesage
     */
    private int ttl = 0;

    /**
     *  Write advertisement into a document. asMimeType is a mime media-type
     *  specification and provides the form of the document which is being
     *  requested. Two standard document forms are defined. 'text/text' encodes
     *  the document in a form nice for printing out and 'text/xml' which
     *  provides an XML format.
     *
     *@param  asMimeType  mime-type requested representation for the returned
     *      document
     *@return             Document document representing the advertisement
     */

    public abstract Document getDocument(MimeMediaType asMimeType);

    /**
     *  returns the source peerid
     *
     *@return    PeerID
     */

    public PeerID getPeerID() {
        return peerid;
    }

    /**
     *  get the primary key
     *
     *@return    primaryKey
     */

    public String getPrimaryKey() {
        return this.primaryKey;
    }

    /**
     *  Returns the current TTL value.
     *
     *@return The current TTL value.
     */

    public int getTTL() {
        return ttl;
    }

    /**
     *  sets the ttl
     *
     *  @param newTTL The new TTL value.
     */

    public void setTTL(int newTTL) {
        ttl = newTTL;
    }

    /**
     *  Decrements TTL
     */

    public void decrementTTL() {

        if (this.ttl > 0) {
            this.ttl--;
        }
    }

    /**
     * Returns the entries of this SrdiMessage
     *
     * @return the entries of this SrdiMessage
     */

    public Collection getEntries() {
        return new ArrayList(entries);
    }

    public void addEntry(String key, String value, long expiration) {
        addEntry(new SrdiMessage.Entry(key, value, expiration));
    }
    
    public void addEntry(SrdiMessage.Entry entry) {
        entries.add(entry);
    }

    /**
     *  Set the Entries for this SrdiMessage.
     *
     *  @param newEntries The entries to be included in this message.
     */

    public void setEntries(Collection newEntries) {
        entries.clear();
        entries.addAll(newEntries);
    }

    /**
     *  Set the source peerid
     *
     *  @param  peerid  the source PeerID
     */

    public void setPeerID(PeerID peerid) {
        this.peerid = peerid;
    }

    /**
     *  Set the primary key
     *
     *  @param  pkey  the primary key
     */

    public void setPrimaryKey(String pkey) {
        this.primaryKey = pkey;
    }

    /**
     *  All messages have a type (in xml this is !doctype) which identifies the
     *  message, if no expiration is defined Default expiration infinite for
     *  entries. This is the amount of time which an entry will live in cache.
     *  After this time, the entry is garbage collected, it also worthy to note
     *  that it is up to the peer caching these entries to honor the lifetime of
     *  the entry, and peer may choose to garbage collect entries based on
     *  quotas, relationship with other peers, etc. *
     *
     *@return    String "jxta:GenSRDI"
     */

    public static String getMessageType() {
        return "jxta:GenSRDI";
    }

    /**
     *  Entries object, which describes each entry described by this message
     *  
     */
    public final static class Entry {

        /**
         *  Entry Expiration expressed in relative time in ms
         */
        public long expiration;

        /**
         *  Entry key attribute
         */
        public String key;

        /**
         *  Entry key value
         */
        public String value;

        /**
         *  {@inheritDoc}
         *
         *  <p/>Expiration time is not considered in calculation.
         **/
        public boolean equals(Object target) {
            
            if (this == target) {
                return true;
            }
            
            if (target instanceof Entry) {
                Entry likeMe = (Entry) target;
                
                return key.equals(likeMe.key) && value.equals(likeMe.value);
            }
            
            return false;
        }
        
        /**
         *  {@inheritDoc}
         *
         *  <p/>Expiration time is not considered in calculation.
         **/
        public int hashCode() {
            int result = 0;
            
            if (null != key) {
                result ^= key.hashCode();
            }
            
            if (null != value) {
                result ^= value.hashCode();
            }
            
            return result;
        }

        /**
         *  Creates a Entry with key, value, and expiration
         *
         *@param  key key attribute
         *@param  value key value
         *@param  expiration expressed in relative time in ms
         */

        public Entry(String key, String value, long expiration) {
            this.key = key;
            this.value = value;
            this.expiration = expiration;
        }
    }
}