org.cg.dao.webcontainer.tomcat.WebAppClassLoader.java Source code

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Here is the source code for org.cg.dao.webcontainer.tomcat.WebAppClassLoader.java

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/*******************************************************************************
    
 * Copyright (c) 2000, 2004 IBM Corporation and others. All rights reserved.
    
 * This program and the accompanying materials are made available under the
    
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
    
 * and is available at http://www.eclipse.org/legal/epl-v10.html
    
 * 
    
 * Contributors: IBM Corporation - initial API and implementation
    
 ******************************************************************************/

package org.cg.dao.webcontainer.tomcat;

import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Enumeration;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 
 * A class loader that combines a plugin class loader with the tomcat class
 * 
 * loader
 */

public class WebAppClassLoader extends URLClassLoader {

    private final static Log logger = LogFactory.getLog(WebAppClassLoader.class);

    private ClassLoader myPluginLoader;

    private DaoBundleURLClassLoader tomcatPluginLoader;

    public WebAppClassLoader(ClassLoader pluginLoader) {

        super(new URL[0]);

        this.myPluginLoader = pluginLoader;

        this.tomcatPluginLoader = new DaoBundleURLClassLoader(Activator.PLUGIN_ID);

    }

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        return super.findClass(name);
    }

    @Override
    public URL findResource(String resource) {
        logger.debug("finding resource " + resource);
        logger.debug(myPluginLoader.toString() + " is finding resource " + resource);
        URL url = myPluginLoader.getResource(resource);
        if (url != null)
            return url;
        logger.debug("tomcat classloader finding resource " + resource);
        url = tomcatPluginLoader.getResource(resource);
        if (url != null)
            return url;
        logger.debug("defer to super classloader to find" + resource);
        return super.findResource(resource);
    }

    @Override
    public Enumeration<URL> findResources(String resources) throws IOException {
        logger.debug("finding resources " + resources);
        logger.debug(myPluginLoader.toString() + " is finding resourced" + resources);

        Enumeration<URL> urls = myPluginLoader.getResources(resources);
        if (urls != null && urls.hasMoreElements())
            return urls;
        logger.debug("tomcat classloader finding resources " + resources);
        urls = tomcatPluginLoader.getResources(resources);
        if (urls != null && urls.hasMoreElements())
            return urls;
        logger.debug("defer to super classloader to find resources " + resources);
        return super.findResources(resources);
    }

    @Override
    public URL getResource(String resName) {
        logger.debug("getting resource: " + resName);

        // 1. check the plugin loader, 2. current loader
        logger.debug(myPluginLoader.toString() + " is loading resource " + resName);
        URL url = myPluginLoader.getResource(resName);
        if (url == null) {
            logger.debug("tomcat classloader is loading resource " + resName);
            return tomcatPluginLoader.getResource(resName);
        }
        return url;

    }

    @Override
    public Enumeration<URL> getResources(String name) throws IOException {
        logger.debug("getting resources " + name);
        logger.debug(myPluginLoader.toString() + " is loading, resource is " + name);
        Enumeration<URL> urls = myPluginLoader.getResources(name);
        if (urls == null) {
            logger.debug("tomcat classloader is loading resource " + name);
            return tomcatPluginLoader.getResources(name);
        }
        return urls;
    }

    public URL[] getURLs() {

        URL[] pluginLoaderURLs;

        if (myPluginLoader instanceof URLClassLoader)
            pluginLoaderURLs = ((URLClassLoader) myPluginLoader).getURLs();
        else
            pluginLoaderURLs = new URL[0];

        URL[] tomcatPluginLoaderURLs = tomcatPluginLoader.getURLs();

        URL[] urls = new URL[pluginLoaderURLs.length + tomcatPluginLoaderURLs.length];

        System.arraycopy(pluginLoaderURLs, 0, urls, 0, pluginLoaderURLs.length);

        System.arraycopy(tomcatPluginLoaderURLs, 0, urls,

                pluginLoaderURLs.length, tomcatPluginLoaderURLs.length);

        return urls;

    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    public Class loadClass(String className) throws ClassNotFoundException {
        logger.debug("loading class : " + className);
        // 1. check tomcat plugin loader, 2. the webapp plugin loader
        Class myClass = null;
        try {
            logger.debug("tomcat classloader is loading class " + className);
            myClass = tomcatPluginLoader.loadClass(className);
        } catch (ClassNotFoundException e) {
            myClass = myPluginLoader.loadClass(className);
            logger.debug("Fail to load class " + className, e);
        } finally {
        }
        return myClass;
    }

}