/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 * 
 * Portions Copyright Apache Software Foundation.
 * 
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License. You can obtain
 * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
 * or glassfish/bootstrap/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
 * Sun designates this particular file as subject to the "Classpath" exception
 * as provided by Sun in the GPL Version 2 section of the License file that
 * accompanied this code.  If applicable, add the following below the License
 * Header, with the fields enclosed by brackets [] replaced by your own
 * identifying information: "Portions Copyrighted [year]
 * [name of copyright owner]"
 * 
 * Contributor(s):
 * 
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */


package org.apache.catalina.startup;


import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleListener;
import com.sun.org.apache.commons.digester.Digester;
import com.sun.org.apache.commons.digester.Rule;
import org.xml.sax.Attributes;


/**
 * <p>Rule that creates a new <code>LifecycleListener</code> instance,
 * and associates it with the top object on the stack (which must
 * implement <code>LifecycleListener</code>).</p>
 */

public class LifecycleListenerRule extends Rule {


    // ----------------------------------------------------------- Constructors


    /**
     * Construct a new instance of this Rule.
     *
     * @param digester Digester we are associated with
     * @param listenerClass Default name of the LifecycleListener
     *  implementation class to be created
     * @param attributeName Name of the attribute that optionally
     *  includes an override name of the LifecycleListener class
     */
    public LifecycleListenerRule(Digester digester, String listenerClass,
                                 String attributeName) {

        super(digester);
        this.listenerClass = listenerClass;
        this.attributeName = attributeName;

    }


    // ----------------------------------------------------- Instance Variables


    /**
     * The attribute name of an attribute that can override the
     * implementation class name.
     */
    private String attributeName;


    /**
     * The name of the <code>LifecycleListener</code> implementation class.
     */
    private String listenerClass;


    // --------------------------------------------------------- Public Methods


    /**
     * Handle the beginning of an XML element.
     *
     * @param attributes The attributes of this element
     *
     * @exception Exception if a processing error occurs
     */
    public void begin(Attributes attributes) throws Exception {

        // Instantiate a new LifecyleListener implementation object
        String className = listenerClass;
        if (attributeName != null) {
            String value = attributes.getValue(attributeName);
            if (value != null)
                className = value;
        }
        Class clazz = Class.forName(className);
        LifecycleListener listener =
            (LifecycleListener) clazz.newInstance();

        // Add this LifecycleListener to our associated component
        Lifecycle lifecycle = (Lifecycle) digester.peek();
        lifecycle.addLifecycleListener(listener);

    }


}