ImplClassClassLoader.java

/*******************************************************************************
 * Copyright (c) 2004, 2010 BREDEX GmbH.
 * 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:
 *     BREDEX GmbH - initial API and implementation and/or initial documentation
 *******************************************************************************/
package org.eclipse.jubula.rc.common.classloader;

import java.net.URLClassLoader;

import org.eclipse.jubula.tools.internal.constants.CommandConstants;

/**
 * This Classloader tries to load the classes with the given ClassLoaders.
 *
 * @author BREDEX GmbH
 * @created 04.05.2006
 */
public class ImplClassClassLoader extends JBUrlClassLoader {

    /** The alternative ClassLoader*/ 
    private ClassLoader m_componentCL;
    
    
    /**
     * Constructor.
     * @param autServerCL the ClassLoader of the AUT-Server
     * @param componentCL ClassLoader of the componentCL
     */
    public ImplClassClassLoader(URLClassLoader autServerCL, 
        ClassLoader componentCL) {
        
        super(autServerCL.getURLs(), autServerCL);
        m_componentCL = componentCL;
    }

    /**
     * 
     * {@inheritDoc}
     * @param name
     * @param resolve
     * @return
     * @throws ClassNotFoundException
     */
    protected synchronized Class loadClass(String name, boolean resolve) 
        throws ClassNotFoundException {
        
        Class c = null;
        // in case of c is an ImplClass
        if ((name.indexOf("tester.adapter.") == -1) //$NON-NLS-1$
                && (name.startsWith(CommandConstants.SWING_IMPLCLASS_PACKAGE)
            || name.startsWith(CommandConstants.SWT_IMPLCLASSES_PACKAGE)
            || (name.indexOf(CommandConstants.JUBULA_EXTENSION_PACKAGE) 
                != -1)
            )) { 
            
            return implLoadClass(name, resolve);
        }
        try {
            // in case of any other class not involved with ImplClasses
            c = super.getParent().loadClass(name);
        } catch (ClassNotFoundException e) {
            // e.g. in case of special AUT-component used in ImplClasses
            c = implLoadClass(name, resolve);
        }
        return c;
    }
    
    /**
     * Tries to load the classes with this ClassLoader and then, if not
     * successful, with the alternative ClassLoader.
     * @param name name
     * @param resolve resolve
     * @return Class
     * @throws ClassNotFoundException ClassNotFoundException
     */
    private Class implLoadClass(String name, boolean resolve) 
        throws ClassNotFoundException {
        
        Class c = null;
        try {
            // first try with parent
            c = super.loadClass(name, resolve);
        }  catch (ClassNotFoundException e) {
            // alternative try
            c = m_componentCL.loadClass(name);
        } 
        return c;
    }
    
    
    /**
     * This method tries to load the classes with the ClassLoaders given to the 
     * Constructor.
     * 
     * @param name the name of the Class
     * {@inheritDoc}
     * @return the loaded Class
     * @throws ClassNotFoundException if no class was found.
     */
    public Class loadClass(String name) throws ClassNotFoundException {
        return loadClass(name, false);
    }
    
}