AbstractInvocationHandler.java

/*
 * Copyright 2014 mango.jfaster.org
 *
 * The Mango Project licenses this file to you 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 org.jfaster.mango.util.reflect;


import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public abstract class AbstractInvocationHandler implements InvocationHandler {

  private static final Object[] NO_ARGS = {};

  @Override
  public final Object invoke(Object proxy, Method method, Object[] args)
      throws Throwable {
    if (args == null) {
      args = NO_ARGS;
    }
    if (args.length == 0 && method.getName().equals("hashCode")) {
      return hashCode();
    }
    if (args.length == 1
        && method.getName().equals("equals")
        && method.getParameterTypes()[0] == Object.class) {
      Object arg = args[0];
      return proxy.getClass().isInstance(arg) && equals(Proxy.getInvocationHandler(arg));
    }
    if (args.length == 0 && method.getName().equals("toString")) {
      return toString();
    }
    return handleInvocation(proxy, method, args);
  }

  protected abstract Object handleInvocation(Object proxy, Method method, Object[] args)
      throws Throwable;

  @Override
  public boolean equals(Object obj) {
    return super.equals(obj);
  }

  @Override
  public int hashCode() {
    return super.hashCode();
  }

  @Override
  public String toString() {
    return super.toString();
  }
}