com.clican.pluto.orm.dynamic.impl.DynamicClassLoader.java Source code

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Here is the source code for com.clican.pluto.orm.dynamic.impl.DynamicClassLoader.java

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/**
 * The Clican-Pluto software suit is Copyright 2009, Clican Company
 * and individual contributors, and is licensed under the GNU LGPL.
 *
 * @author clican
 *
 */
package com.clican.pluto.orm.dynamic.impl;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Collection;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;

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

import com.clican.pluto.orm.dynamic.inter.IDirectory;

/**
 * This class extends <code>URLClassLoader</code>. It can be used to dynamically
 * load class and override exist class with new definition. The caller must
 * replace the
 * <code>Thread.currentThread().setContextClassLoader(ClassLoader classLoader)</code>
 * with this class.
 * <p>
 * Because the Hibernate will use the
 * <code>Thread.currentThread().getContextClassLoader()</code> as the class
 * loader for POJO loading.
 * <p>
 * For the Spring we also need set the beanClassLoader for
 * LocalSessionFactoryBean to replace the default ResourceClassLoader.
 * 
 * For details, please refer to <code>LocalWrapSessionFactoryBean</code>
 * 
 * @since 0.0.1
 * @author clican
 * 
 */
public class DynamicClassLoader extends ClassLoader {
    /**
     * Logger for this class
     */
    private static final Log log = LogFactory.getLog(DynamicClassLoader.class);

    private String tempORMCfgPojoFolder;

    private URLClassLoader urlClassLoader;

    private Map<String, Class<?>> loadedDynamicClasses = new HashMap<String, Class<?>>();

    private ClassLoader parent;

    public DynamicClassLoader() {
        this.parent = Thread.currentThread().getContextClassLoader();
        log.debug(parent.toString());
        try {
            this.parent.loadClass(IDirectory.class.getName());
        } catch (Exception e) {
            log.error("", e);
        }

    }

    public void setTempORMCfgPojoFolder(String tempORMCfgPojoFolder) {
        this.tempORMCfgPojoFolder = tempORMCfgPojoFolder;
    }

    public Collection<Class<?>> getLoadedDynamicClasses() {
        return loadedDynamicClasses.values();
    }

    /**
     * This will be initialize by Spring Framework.
     * 
     * @throws MalformedURLException
     * @throws ClassNotFoundException
     */
    public void init() throws MalformedURLException, ClassNotFoundException {
        File file = new File(tempORMCfgPojoFolder);
        if (!file.exists()) {
            file.mkdirs();
        }
        urlClassLoader = new URLClassLoader(new URL[] { file.toURI().toURL() }, parent);
        loadAllClasses(file);
    }

    private void loadAllClasses(File dir) throws ClassNotFoundException {
        if (dir.isDirectory()) {
            for (File file : dir.listFiles()) {
                loadAllClasses(file);
            }
        } else {
            if (dir.getName().contains("class")) {
                String clazz = dir.getAbsolutePath().replaceAll("\\\\", "/")
                        .replaceAll(new File(tempORMCfgPojoFolder).getAbsolutePath().replaceAll("\\\\", "/") + "/",
                                "")
                        .replaceAll("/", "\\.").replaceAll("\\.class", "");
                if (log.isDebugEnabled()) {
                    log.debug("class=" + clazz);
                }
                Class<?> c = urlClassLoader.loadClass(clazz);
                loadedDynamicClasses.put(c.getName(), c);
            }
        }
    }

    public synchronized void refreshClasses() throws ClassNotFoundException {
        URL[] urls = urlClassLoader.getURLs();
        urlClassLoader = new URLClassLoader(urls, urlClassLoader.getParent());
        File file = new File(tempORMCfgPojoFolder);
        if (!file.exists()) {
            file.mkdirs();
        }
        loadedDynamicClasses.clear();
        loadAllClasses(file);
    }

    @Override
    public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (loadedDynamicClasses.containsKey(name)) {
            return loadedDynamicClasses.get(name);
        } else {
            return urlClassLoader.loadClass(name);
        }
    }

    @Override
    public Enumeration<URL> findResources(String name) throws IOException {
        if (urlClassLoader == null) {
            return super.findResources(name);
        } else {
            return urlClassLoader.findResources(name);
        }

    }

}

// $Id: DynamicClassLoader.java 700 2010-02-10 02:50:12Z clican $