discoidentityhandler.java

一款即时通讯软件

/*
 *   License
 *
 * The contents of this file are subject to the Jabber Open Source License
 * Version 1.0 (the "License").  You may not copy or use this file, in either
 * source code or executable form, except in compliance with the License.  You
 * may obtain a copy of the License at http://www.jabber.com/license/ or at
 * http://www.opensource.org/.  
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 *   Copyrights
 *
 * Portions created by or assigned to Jabber.com, Inc. are 
 * Copyright (c) 2000 Jabber.com, Inc.  All Rights Reserved.  Contact
 * information for Jabber.com, Inc. is available at http://www.jabber.com/.
 *
 * Portions Copyright (c) 1999-2000 David Waite 
 *
 *   Acknowledgements
 * 
 * Special thanks to the Jabber Open Source Contributors for their
 * suggestions and support of Jabber.
 * 
 *   Changes
 *
 * @author  $Author: chris $
 *
 * j.komzak
 * Changed to DiscoIdentityHandler
 *
 */

package edu.ou.kmi.buddyspace.plugins.disco.xml;

import org.jabber.jabberbeans.*;
import org.jabber.jabberbeans.sax.*;

import org.xml.sax.AttributeList;
import org.xml.sax.SAXException;

/**
 * Handler class to build DiscoIdentity objects. This creates xml structure.
 */
public class DiscoIdentityHandler
    extends SubHandler
{
    /** used to capture data between element tags */
    private StringBuffer elementChars;

    /** builder for DiscoIdentity objects */
    private DiscoIdentityBuilder builder;

    /**
     * Creates a new <code>DiscoIdentityHandler</code> instance.
     */
    public DiscoIdentityHandler() {
	super();
	builder = new DiscoIdentityBuilder();
    };

    /**
     * Gets called when the underlying engine decides to pass an entity and
     * all sub-entities off to your subhandler.<p>
     *
     * Upon seeing the element that this subhandler handles, we call this
     * constructor, passing in the attributes.
     *
     * @param attributes a value of type 'AttributeList'
     */
    public void startHandler(String name, AttributeList attributes)
	throws SAXException
    {
	elementChars = new StringBuffer();
        builder.reset();
        
	builder.setAttributes(attributes);
    };
    
    /**
     * This is an exact copy of the start element in the main handler.
     *
     * @param name string that holds the element name
     * @param attributes AttributeList of attributes going with this element
     * @exception SAXException thrown on error (unexpected element)
     */
    public void handleStartElement(String name, AttributeList attributes)
	throws SAXException
    {
	elementChars=new StringBuffer();
    }
    
    /**
     * This is an exact copy of the end element in the main handler
     *
     * @param name string holding the element name
     * @exception SAXException thrown on error
     */
    public void handleEndElement(String name)
	throws SAXException
    { }

    /**
     * This is an exact copy of the characters function in the main handler
     *
     * @param ch character string detected
     * @param start start position
     * @param length length of string
     * @exception SAXException thrown on error
     */
    public void characters(char[] ch, int start, int length)
	throws SAXException
    {
	elementChars.append(ch, start, length);
    }
    
    /**
     * Stophandler is the same as end element, except that it is called saying
     * that the subhandler is no longer in scope.
     *
     * @param nil a value of type ''
     */
    public Object stopHandler(String name)
	throws SAXException
    {
        try {
            return builder.build();
        }
        catch (InstantiationException e) {
            e.fillInStackTrace();
            throw new SAXException(e);
        }
    }

    /**
     * received data handler from subobjects. Ignored since this
     * handler never creates child handlers
     *
     * @param subHandler child subhandler which is returning
     * @param child Object which the child is returning
     */
    public void receiveChildData(SubHandler subHandler, Object child) {
        //Add the returned object to the child vector
    }
}