EsperListenerParser.java

/*
 * OpenCredo-Esper - simplifies adopting Esper in Java applications. 
 * Copyright (C) 2010  OpenCredo Ltd.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package org.opencredo.esper.config.xml;

import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.parsing.BeanComponentDefinition;
import org.springframework.beans.factory.support.ManagedSet;
import org.springframework.beans.factory.xml.ParserContext;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

/**
 * Parses the listeners block in the Spring custom namespace support.
 * 
 * @author Russ Miles (russ.miles@opencredo.com)
 * 
 */
public class EsperListenerParser {

    /**
     * Parses out a set of configured esper statement listeners.
     * 
     * @param element
     *            the esper listeners element
     * @param parserContext
     *            the parser's current context
     * @return a list of configured esper statement listeners
     */
    @SuppressWarnings("unchecked")
    public ManagedSet parseListeners(Element element, ParserContext parserContext) {
        ManagedSet listeners = new ManagedSet();
        NodeList childNodes = element.getChildNodes();
        for (int i = 0; i < childNodes.getLength(); i++) {
            Node child = childNodes.item(i);
            if (child.getNodeType() == Node.ELEMENT_NODE) {
                Element childElement = (Element) child;
                String localName = child.getLocalName();
                if ("bean".equals(localName)) {
                    BeanDefinitionHolder holder = parserContext.getDelegate().parseBeanDefinitionElement(childElement);
                    parserContext.registerBeanComponent(new BeanComponentDefinition(holder));
                    listeners.add(new RuntimeBeanReference(holder.getBeanName()));
                } else if ("ref".equals(localName)) {
                    String ref = childElement.getAttribute("bean");
                    listeners.add(new RuntimeBeanReference(ref));
                }
            }
        }
        return listeners;
    }

}