GroovyWarClassLoader.java

/*
 * $Id: GroovyWarClassLoader.java 524 2006-01-08 09:30:40Z jdonnerstag $
 * $Revision: 524 $ $Date: 2006-01-08 01:30:40 -0800 (Sun, 08 Jan 2006) $
 * 
 * ==================================================================== 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 wicket.contrib.groovy;

import groovy.lang.GroovyClassLoader;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.codehaus.groovy.control.CompilationFailedException;

import wicket.util.string.Strings;

/**
 * I had some issues with the GroovyClassLoader (1.0.7-beta) which failed to
 * load a groovy files contained in the same war file. E.g.
 * 
 * <pre>
 *  wicket-examples.war!/web-inf/classes/groovy/A.groovy
 *  wicket-examples.war!/web-inf/classes/groovy/B.groovy
 * 
 *  public class A {
 *     public A() {
 *        B b = new B()
 *     }
 *  }
 * </pre>
 * 
 * GroovyClassLoader did not load Groovy class B.
 * 
 * @author Juergen Donnerstag
 */
public class GroovyWarClassLoader extends GroovyClassLoader
{
	/** Logger */
	final private static Log log = LogFactory.getLog(GroovyWarClassLoader.class);

	/**
	 * Constructor
	 * 
	 * @param loader
	 *            The servlet's class loader
	 */
	public GroovyWarClassLoader(ClassLoader loader)
	{
		super(loader);
	}

	/**
	 * First try parent's implementation. If it fails, it'll throw a
	 * ClassCastException. Catch it and than apply additional means to load the
	 * class.
	 * 
	 * @param name
	 *            Class name incl. package
	 * @return The Class loaded, if found
	 * @throws ClassNotFoundException,
	 *             if class could not be loaded
	 */
	protected Class findClass(final String name) throws ClassNotFoundException
	{
		try
		{
			// Try Groovies default implementation first
			return super.findClass(name);
		}
		catch (ClassNotFoundException ex)
		{
			log.debug("class name: " + name);

			// classname => filename
			String filename = Strings.replaceAll(name, ".", "/") + ".groovy";

			// File exists?
			final URL url = getResource(filename);
			if (url != null)
			{
				try
				{
					// Get Groovy to parse the file and create the Class
					final InputStream in = url.openStream();
					if (in != null)
					{
						Class clazz = parseClass(in);
						if (clazz != null)
						{
							return clazz;
						}
					}
					else
					{
						log.warn("Groovy file not found: " + filename);
					}
				}
				catch (CompilationFailedException e)
				{
					throw new ClassNotFoundException("Error parsing groovy file: "
							+ filename, e);
				}
				catch (IOException e)
				{
					throw new ClassNotFoundException("Error reading groovy file: "
							+ filename, e);
				}
				catch (Throwable e)
				{
					throw new ClassNotFoundException("Error while reading groovy file: "
							+ filename, e);
				}
			}

			throw ex;
		}
	}
}