org.aspectj.weaver.bcel.ExtensibleURLClassLoader.java Source code

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Here is the source code for org.aspectj.weaver.bcel.ExtensibleURLClassLoader.java

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/* *******************************************************************
 * 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 
 *     Andy Clement
 *     Roy Varghese - Bug 473555
 * ******************************************************************/

package org.aspectj.weaver.bcel;

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.BCException;
import org.aspectj.weaver.UnresolvedType;

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;
        UnresolvedType unresolvedType = null;
        try {
            unresolvedType = UnresolvedType.forName(name);
        } catch (BCException bce) {
            if (bce.getMessage().indexOf("nameToSignature") == -1) {
                bce.printStackTrace(System.err);
            }
            return null;
        }
        ClassPathManager.ClassFile classFile = classPath.find(unresolvedType);
        if (classFile != null) {
            try {
                b = FileUtil.readAsByteArray(classFile.getInputStream());
            } finally {
                classFile.close();
            }
        }
        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);
    }

    @Override
    public void close() throws IOException {
        super.close();
        classPath.closeArchives();
    }

}