org.aspectj/weaver/src/org/aspectj/weaver/ExtensibleURLClassLoader.java

/* *******************************************************************
 * Copyright (c) 2004 IBM Corporation
 * 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: 
 *     Matthew Webster, Adrian Colyer, 
 *     Martin Lippert     initial implementation 
 * ******************************************************************/

package org.aspectj.weaver;

import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.security.CodeSource;

import org.aspectj.util.FileUtil;
import org.aspectj.weaver.bcel.ClassPathManager;

public abstract class ExtensibleURLClassLoader extends URLClassLoader {
	
	private ClassPathManager classPath;
	
	public ExtensibleURLClassLoader (URL[] urls, ClassLoader parent) {
		super(urls,parent);

//		System.err.println("? ExtensibleURLClassLoader.<init>() path=" + WeavingAdaptor.makeClasspath(urls));
		try {
			classPath = new ClassPathManager(FileUtil.makeClasspath(urls),null);
		}
		catch (ExceptionInInitializerError ex) {
			ex.printStackTrace(System.out);
			throw ex;
		}
	}

	protected void addURL(URL url) {
		super.addURL(url);  // amc - this call was missing and is needed in
		                 // WeavingURLClassLoader chains
		classPath.addPath(url.getPath(),null);
	}
	
	protected Class findClass(String name) throws ClassNotFoundException {
//		System.err.println("? ExtensibleURLClassLoader.findClass(" + name + ")");
		try {
			byte[] bytes = getBytes(name);
			if (bytes != null) {
				return defineClass(name,bytes);
			}
			else {
				throw new ClassNotFoundException(name);
			}
		}
		catch (IOException ex) {
			throw new ClassNotFoundException(name);
		}
	}

	protected Class defineClass(String name, byte[] b, CodeSource cs) throws IOException {
//		System.err.println("? ExtensibleURLClassLoader.defineClass(" + name + ",[" + b.length + "])");
		return defineClass(name, b, 0, b.length, cs);
	}

	protected byte[] getBytes (String name) throws IOException {
		byte[] b = null;
		ClassPathManager.ClassFile classFile = classPath.find(UnresolvedType.forName(name));
		if (classFile != null) {
			b = FileUtil.readAsByteArray(classFile.getInputStream());
		}
		return b;
	}

	private Class defineClass(String name, byte[] bytes /*ClassPathManager.ClassFile classFile*/) throws IOException {
		String packageName = getPackageName(name);
		if (packageName != null) {
			Package pakkage = getPackage(packageName);
			if (pakkage == null) {
				definePackage(packageName,null,null,null,null,null,null,null);
			}
		}
		
		return defineClass(name, bytes, null);
	}

	private String getPackageName (String className) {
		int offset = className.lastIndexOf('.');
		return (offset == -1)? null : className.substring(0,offset);  
	}

}