org.romaframework.core.classloader.RomaClassLoader.java Source code

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Here is the source code for org.romaframework.core.classloader.RomaClassLoader.java

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/*
 * Copyright 2006-2007 Luca Garulli (luca.garulli--at--assetdata.it)
 *
 * Licensed under the Apache 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.apache.org/licenses/LICENSE-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.romaframework.core.classloader;

import java.net.URL;
import java.net.URLClassLoader;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.romaframework.core.flow.Controller;

/**
 * Roma Class Loader. It overrides default class loading by reloading Roma annotation if any.
 * 
 * @author Luca Garulli (luca.garulli--at--assetdata.it)
 */
public class RomaClassLoader extends URLClassLoader {

    private Log log = LogFactory.getLog(RomaClassLoader.class);
    // private boolean classPathSetted = false;
    private static Map<String, Class<?>> reloadedClasses;

    public RomaClassLoader() {
        super(new URL[] {});
    }

    public RomaClassLoader(URL[] urls) {
        super(urls);
    }

    /**
     * Try to find the class between reloaded class, otherwise delegate the loading to the superclass.
     * 
     * @param name
     *          Class name
     * @return Class if found
     */
    @Override
    public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (reloadedClasses == null) {
            return super.loadClass(name);
        }

        Class<?> cls = null;
        synchronized (reloadedClasses) {
            cls = reloadedClasses.get(name);
        }

        if (cls == null) {
            cls = super.loadClass(name);
        }

        return cls;
    }

    /**
     * Explicit reload a class
     * 
     * @param iClassName
     * @return
     * @throws ClassNotFoundException
     */
    public Class<?> reloadClass(String iClassName) throws ClassNotFoundException {
        init();

        Class<?> cls;

        synchronized (this) {
            if (reloadedClasses == null) {
                reloadedClasses = new HashMap<String, Class<?>>();
            }
        }

        synchronized (reloadedClasses) {
            // LOAD CLASS FOR REAL
            cls = super.findClass(iClassName);
            reloadedClasses.put(iClassName, cls);

            signalToAllListeners(cls);
        }

        log.warn("[RomaClassLoader.reloadClass] Reloaded class: " + cls + ", hash: " + cls.hashCode());

        return cls;
    }

    private void init() {
        /*
         * if (!classPathSetted) { synchronized (this) { if (!classPathSetted) { classPathSetted = true; String classPaths[] =
         * Roma.component(ResourceResolver.class).getClassPaths(); for (String classPath : classPaths) { for (String item :
         * classPath.split(File.pathSeparator)) { try { addURL(new File(item).toURI().toURL()); } catch (MalformedURLException e) {
         * log.error("[RomaClassLoader.init] Bad url setting classpath: " + item); } } } } } }
         */
    }

    /**
     * Signal to all registered listeners the class loading event.
     * 
     * @param cls
     *          Just loaded class
     */
    private void signalToAllListeners(Class<?> cls) {
        if (Controller.getInstance().getListeners(ClassLoaderListener.class) != null) {
            for (Object obj : Controller.getInstance().getListeners(ClassLoaderListener.class)) {
                ClassLoaderListener l = (ClassLoaderListener) obj;
                if (l != null) {
                    l.onClassLoading(cls);
                }
            }
        }
    }
}