org.sakaiproject.util.DefaultEntityHandler.java Source code

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Here is the source code for org.sakaiproject.util.DefaultEntityHandler.java

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/**********************************************************************************
 * $URL: https://source.sakaiproject.org/svn/kernel/trunk/kernel-util/src/main/java/org/sakaiproject/util/DefaultEntityHandler.java $
 * $Id: DefaultEntityHandler.java 51317 2008-08-24 04:38:02Z csev@umich.edu $
 ***********************************************************************************
 *
 * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008 Sakai Foundation
 *
 * Licensed under the Educational Community License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.opensource.org/licenses/ECL-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 **********************************************************************************/

package org.sakaiproject.util;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.sakaiproject.entity.api.Entity;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * This class is required by the SAX parser to parse into. Rather than use the ContentHandler interface
 * this class and the underlying DefautlHandler implements all the required methods of ContentHandler
 * and others, removing most of the implementation load from those producing extensions.
 * 
 * DefaultEntityHandlers are create by SAXReaders and consume SAXEvents building an Entity, which is then
 * retrieved once parsing is complete with the getEntity() method.
 * 
 * @author ieb
 */
public class DefaultEntityHandler extends DefaultHandler implements SAXEntityHandler {

    private static final Log log = LogFactory.getLog(DefaultEntityHandler.class);

    protected ContentHandler ch;

    protected int remove = -1;

    protected int nesting = 0;

    protected Entity entity;

    protected Entity container;

    /**
     * 
     */
    public DefaultEntityHandler() {
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.xml.sax.helpers.DefaultHandler#endElement(java.lang.String,
     *      java.lang.String, java.lang.String)
     */
    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (ch != null) {
            ch.endElement(uri, localName, qName);
        }
        if (remove == nesting) {
            ch = null;
        }
        nesting--;
    }

    public boolean doStartElement(String uri, String localName, String qName, Attributes attributes)
            throws SAXException {

        nesting++;
        if (ch != null) {
            ch.startElement(uri, localName, qName, attributes);
            return false;
        } else {
            if ("properties".equals(qName)) {
                ch = entity.getProperties().getContentHander();
                ch.startElement(uri, localName, qName, attributes);
                remove = nesting;
                return false;
            }
            return true;
        }

    }

    /*
     * (non-Javadoc)
     * 
     * @see org.xml.sax.helpers.DefaultHandler#startElement(java.lang.String,
     *      java.lang.String, java.lang.String, org.xml.sax.Attributes)
     */
    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes)
            throws SAXException {
        if (!doStartElement(uri, localName, qName, attributes)) {
            super.startElement(uri, localName, qName, attributes);
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.sakaiproject.util.DefaultEntityHandler#getEntity()
     */
    public Entity getEntity() {
        return entity;
    }

    /**
     * @param contentHandler
     * @throws SAXException 
     */
    protected void setContentHandler(ContentHandler contentHandler, String uri, String localName, String qName,
            Attributes attributes) throws SAXException {
        if (ch == null) {
            ch = contentHandler;
            remove = nesting;
            ch.startElement(uri, localName, qName, attributes);
        } else {
            log.warn("Attempted to reset child content handler ");
        }

    }

    /**
     * @param container2
     */
    public void setContainer(Entity container) {
        this.container = container;
    }

}