org.apache.commons.proxy.invoker
Class DuckTypingInvoker

java.lang.Object
  org.apache.commons.proxy.invoker.DuckTypingInvoker

All Implemented Interfaces:

Invoker

public class DuckTypingInvoker
extends Object
implements Invoker

An invoker which supports "duck typing", meaning that it finds a matching method on the object returned from the target provider and invokes it. This class is useful for adapting an existing class to an interface it does not implement.

Example:

 public class LegacyDuck // Does not implement interface!
 {
   public void quack()
   {
     // Quacking logic...
   }
 }
 

 public interface Duck
 {
   public void quack();
 }
 

 ObjectProvider targetProvider = new ConstantProvider(new LegacyDuck()); // Always returns a "legacy" duck
 DuckTypingInvoker invoker = new DuckTypingInvoker(targetProvider);
 Duck duck = ( Duck )proxyFactory.createInvokerProxy( invoker, new Class[] { Duck.class } );
 

Constructor Summary

DuckTypingInvoker(ObjectProvider targetProvider)

Method Summary

Object

invoke(Object proxy, Method method, Object[] arguments) "Invokes" the method.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DuckTypingInvoker

public DuckTypingInvoker(ObjectProvider targetProvider)

Method Detail

invoke

public Object invoke(Object proxy,
                     Method method,
                     Object[] arguments)
              throws Throwable

Description copied from interface: Invoker

"Invokes" the method. Implementation should throw a InvokerException if problems arise while trying to invoke the method.

Specified by:

invoke in interface Invoker

Parameters:

proxy - the proxy object

method - the method being invoked

arguments - the arguments

Returns:

the return value

Throws:

Throwable - thrown by the implementation