listmessageprocessor.java

jxta-cms-src-2.4.zip 是官网上的比较稳定的CMS源代码。目前是最稳定的高版本。

/*
 *  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 THE APACHE SOFTWARE FOUNDATION 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: ListMessageProcessor.java,v 1.16 2006/02/07 20:43:50 bondolo Exp $
 *
 */
package net.jxta.share;

import java.io.IOException;
import java.util.Vector;

import net.jxta.endpoint.ByteArrayMessageElement;
import net.jxta.endpoint.EndpointAddress;
import net.jxta.endpoint.Messenger;
import net.jxta.endpoint.Message;
import net.jxta.endpoint.MessageElement;
import net.jxta.endpoint.InputStreamMessageElement;

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

/**
 *  This class implements List Message Processor. It handles all List requests
 *  from clients for this service.
 */

public class ListMessageProcessor extends MessageProcessor {

    private Vector listeners = null;
    private String subString = null;
    private final static transient Logger LOG = Logger.getLogger(ListMessageProcessor.class.getName());


    /**
     *  Constructor for the ListMessageProcessor object
     *
     *@param  cms  Description of the Parameter
     */
    public ListMessageProcessor(CMS cms) {
        super(cms);
    }


    /**
     *  Gets the queryParameters attribute of the ListMessageProcessor object
     *
     *@param  message  Description of the Parameter
     */
    protected void getQueryParameters(Message message) {
        try {
            subString = CMS.popString(message, CMS.QUERY_SUBSTRING);
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("substring query " + subString);
            }

            //notify all of the SearchListeners that a new query has been
            // recieved
            if (listeners != null) {
                for (int a = 0; a < listeners.size(); a++) {
                    ((SearchListener) listeners.elementAt(a))
                            .queryReceived(subString);
                }
            }
        } catch (IOException e) {
            if (LOG.isEnabledFor(Level.ERROR)) {
                LOG.error("could not get QUERY_SUBSTRING tag");
            }
        }
        if (subString == null) {
            subString = "";
        }

        subString = subString.toLowerCase();
    }


    /**
     *  Gets the match attribute of the ListMessageProcessor object
     *
     *@param  cadv  Description of the Parameter
     *@return       The match value
     */
    protected boolean isMatch(ContentAdvertisement cadv) {
        if (subString == null) {
            return true;
        }

        // check if the name contains the substring
        String name = cadv.getName();
        if (name != null) {
            name = name.toLowerCase();
            if (name.indexOf(subString) != -1) {
                return true;
            }
        }

        // check if the description contains the substring
        String desc = cadv.getDescription();
        if (desc != null) {
            desc = desc.toLowerCase();
            if (desc.indexOf(subString) != -1) {
                return true;
            }
        }

        return false;
    }


    /**
     *  Add a SearchListener object to monitor the search queries recieved.
     *
     *@param  sl  the SearchListener to add
     *@see        SearchListener
     *@see        CMS#addSearchListener(SearchListener)
     *@see        #removeSearchListener(SearchListener)
     */
    public void addSearchListener(SearchListener sl) {
        if (listeners == null) {
            listeners = new Vector();
        }
        listeners.addElement(sl);
    }


    /**
     *  Description of the Method
     *
     *@param  message  Description of the Parameter
     */
    protected void process(Message message) {
        // get the endpoint messenger for the result Peer
        Messenger messenger = null;
        try {
            String addrStr = CMS.popString(message, CMS.RETURN_ADDRESS);

            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("ListMessageProcessor " + addrStr);
            }
            EndpointAddress endpointAddress = new EndpointAddress(addrStr);

            messenger = getEndpointService().getMessenger(endpointAddress);
        } catch (IOException e) {
            if (LOG.isEnabledFor(Level.ERROR)) {
                LOG.error("could not get endpoint address");
            }
            return;
        }

        // create a new result message
        Message resultMsg = new Message();

        // get the list of shared content
        Content[] clist = getContentManager().getContent();

        // load the query parameters of the list request
        getQueryParameters(message);

        int count = 0;
        ContentAdvertisement adv = null;
        String tag;
        for (int i = 0; i < clist.length; i++) {
            // get the content advertisement
            adv = clist[i].getContentAdvertisement();

            // check if the advertisement matches the query
            if (isMatch(adv)) {
                tag = CMS.CONTENT_ADVERTISEMENT + (count++);

                // set the address for this content
                adv.setAddress(getEndpointAddress());
                try {
                    resultMsg.addMessageElement(
                            new InputStreamMessageElement(tag, CMS.encodeAs
                            , adv.getDocument(CMS.encodeAs).getStream(), null));
                } catch (Exception e) {
                    if (LOG.isEnabledFor(Level.ERROR)) {
                        LOG.error("could not add element to message");
                    }
                }
            }
        }

        resultMsg.addMessageElement(
                new ByteArrayMessageElement(CMS.MESSAGE_TYPE, CMS.encodeAs
                , CMS.LIST_RESULT.getBytes(), null));

        // resultMsg.setBytes(CMS.MESSAGE_TYPE, CMS.LIST_RESULT.getBytes());

        MessageElement elem = null;
        elem = message.getMessageElement(CMS.REQUEST_ID);

        // Remove the element from the original message
        message.removeMessageElement(elem);

        // Add it to the new message
        resultMsg.addMessageElement(elem);

        resultMsg.addMessageElement(
                new ByteArrayMessageElement(CMS.ADVERTISEMENT_COUNT, CMS.encodeAs
                , Integer.toString(count).getBytes(), null));

        // resultMsg.setBytes(CMS.ADVERTISEMENT_COUNT, Integer.toString(count).getBytes());

        // send the result
        try {
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("send results");
            }
            messenger.sendMessage(resultMsg);
        } catch (IOException e) {
            if (LOG.isEnabledFor(Level.ERROR)) {
                LOG.error("could not send message");
            }
        }
    }


    /**
     *@param  sl  the SearchListener object to remove.
     *@see        SearchListener
     *@see        CMS#removeSearchListener(SearchListener)
     *@see        #addSearchListener(SearchListener)
     */
    public void removeSearchListener(SearchListener sl) {
        if (listeners != null) {
            listeners.removeElement(sl);
        }
    }
}