WrappedInvocationHandler.java

package games.strategy.triplea.util;

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

public class WrappedInvocationHandler implements InvocationHandler {
  private final Object m_delegate;

  public WrappedInvocationHandler(final Object delegate) {
    if (delegate == null) {
      throw new IllegalArgumentException("delegate cant be null");
    }
    m_delegate = delegate;
  }

  public boolean wrappedEquals(final Object other) {
    if (other == this) {
      return true;
    }
    if (Proxy.isProxyClass(other.getClass()) && Proxy.getInvocationHandler(other) instanceof WrappedInvocationHandler) {
      final WrappedInvocationHandler otherWrapped = (WrappedInvocationHandler) Proxy.getInvocationHandler(other);
      return otherWrapped.m_delegate.equals(m_delegate);
    }
    return false;
  }

  public boolean shouldHandle(final Method method, final Object[] args) {
    if (method.getName().equals("equals") && args != null && args.length == 1) {
      return true;
    } else if (method.getName().equals("hashCode") && args == null) {
      return true;
    }
    return false;
  }

  public Object handle(final Method method, final Object[] args) {
    if (method.getName().equals("equals") && args != null && args.length == 1) {
      return wrappedEquals(args[0]);
    } else if (method.getName().equals("hashCode") && args == null) {
      return wrappedashCode();
    } else {
      throw new IllegalStateException("how did we get here");
    }
  }

  public int wrappedashCode() {
    return m_delegate.hashCode();
  }

  @Override
  public Object invoke(final Object arg0, final Method arg1, final Object[] arg2) throws Throwable {
    if (shouldHandle(arg1, arg2)) {
      return handle(arg1, arg2);
    }
    throw new IllegalStateException("not configured");
  }
}