LocalClassLoader.java

package com.avaje.ebean.enhance.agent;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;

/**
 * This class loader is used to load any classes (typically super classes)
 * during enhancement process (avoiding the application class loaders).
 */
public class LocalClassLoader extends URLClassLoader {

	public LocalClassLoader(URL[] urls, ClassLoader loader) {
		super(urls, loader);
	}

	protected synchronized Class<?> loadClass(String name, boolean resolve)
			throws ClassNotFoundException {
		
		if (name.startsWith("java.")) {
			// we cannot reload these classes due to security constraints
			return super.loadClass(name, resolve);
		}
		Class<?> c = super.findLoadedClass(name);
		if (c != null) {
			return c;
		}
		String resource = name.replace('.', '/') + ".class";

		
		try {
			// read the class bytes, and define the class
			URL url = super.getResource(resource);
			if (url == null) {
				throw new ClassNotFoundException(name);
			}
			
			File f = new File("build/bin/"+resource);
			System.out.println("FileLen:"+f.length()+"  "+f.getName());
			
			InputStream is = url.openStream();
			try {
				ByteArrayOutputStream os = new ByteArrayOutputStream();
				byte[] b = new byte[2048];
				int count;
				while ((count = is.read(b, 0, 2048)) != -1) {
					os.write(b, 0, count);
				}
				byte[] bytes = os.toByteArray();
				System.err.println("bytes: "+bytes.length+" "+resource);
				return defineClass(name, bytes, 0, bytes.length);
			} finally {
				if (is != null) {
					is.close();
				}
			}
		} catch (SecurityException e) {
			return super.loadClass(name, resolve);
		} catch (IOException e) {
			throw new ClassNotFoundException(name, e);
		}
	}

}