CglibProxyBytecodeGenerator.java

package org.hotswap.agent.plugin.proxy.hscglib;

import java.lang.reflect.Method;

import org.hotswap.agent.plugin.proxy.ProxyBytecodeGenerator;

/**
 * Creates new bytecode for a Cglib proxy. Changed Classes have to be loaded alreadyin the App classloader.
 * 
 * @author Erki Ehtla
 * 
 */
public class CglibProxyBytecodeGenerator implements ProxyBytecodeGenerator {
	private GeneratorParams params;
	
	public CglibProxyBytecodeGenerator(GeneratorParams params) {
		super();
		this.params = params;
	}
	
	public byte[] generate() throws Exception {
		Method genMethod = getGenerateMethod(params.getGenerator());
		if (genMethod == null)
			throw new RuntimeException("No generation Method found for redefinition!");
		return (byte[]) genMethod.invoke(params.getGenerator(), params.getParam());
	}
	
	/**
	 * Retrieves the actual Method that generates and returns the bytecode
	 * 
	 * @param generator
	 *            GeneratorStrategy instance
	 * @return Method that generates and returns the bytecode
	 */
	private Method getGenerateMethod(Object generator) {
		Method[] methods = generator.getClass().getMethods();
		for (Method method : methods) {
			if (method.getName().equals("generate") && method.getReturnType().getSimpleName().equals("byte[]")
					&& method.getParameterTypes().length == 1) {
				return method;
			}
		}
		return null;
	}
}