javataskflowletclassloader.java

一个java写的business process management系统

/*
 * Copyright (c) 2003, Alexander Greif
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Flow4J-Eclipse project nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

package net.orthanc.flow4j.designer.core;

import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLStreamHandlerFactory;
import java.util.List;

import net.orthanc.flow4j.runtime.ITaskFlowlet;

/**
 * This classloader can find a task flowlet instance in the current 
 * flow4j project.
 * @author agreif
 */
public class JavaTaskFlowletClassLoader extends URLClassLoader {

	/**
	 * TODO
	 * @param urls
	 * @param parent
	 */
	public JavaTaskFlowletClassLoader(URL[] urls, ClassLoader parent) {
		super(urls, parent);
		// TODO Auto-generated constructor stub
	}

	/**
	 * TODO
	 * @param urls
	 */
	public JavaTaskFlowletClassLoader(URL[] urls) {
		super(urls);
		// TODO Auto-generated constructor stub
	}

	/**
	 * TODO
	 * @param urls
	 * @param parent
	 * @param factory
	 */
	public JavaTaskFlowletClassLoader(
		URL[] urls,
		ClassLoader parent,
		URLStreamHandlerFactory factory) {
		super(urls, parent, factory);
		// TODO Auto-generated constructor stub
	}

	/**
	 * @param classpathEntries
	 * @param parent
	 */
	public JavaTaskFlowletClassLoader(List classpathEntries, ClassLoader parent) {
		super(
			(URL[]) classpathEntries.toArray(new URL[classpathEntries.size()]),
			parent);
	}

	/**
	 * Returns a task flowlet instance or throws
	 * a ClassNotFoundException if it was not found.
	 * @param taskClassName
	 * @return
	 * @throws ClassNotFoundException
	 */
	public ITaskFlowlet getTaskInstance(String taskClassName)
		throws
			ClassNotFoundException,
			Throwable {
		try {
			ITaskFlowlet taskInstance =
				(ITaskFlowlet) Class
					.forName(taskClassName, true, this)
					.newInstance();
			return taskInstance;
		} catch (InstantiationException e) {
			//Flow4JPlugin.log(e);
			throw e;
		} catch (IllegalAccessException e) {
			//Flow4JPlugin.log(e);
			throw e;
		} catch (ClassNotFoundException e) {
			// do nothing
		} catch (Throwable e) {
			//Flow4JPlugin.log(e);
			throw e;
		}

		throw new ClassNotFoundException();
	}

}