uk.ac.starlink.util

Class MultiplexInvocationHandler<T>

java.lang.Object

uk.ac.starlink.util.MultiplexInvocationHandler<T>

All Implemented Interfaces:

InvocationHandler

public class MultiplexInvocationHandler<T>
extends Object
implements InvocationHandler

Used to generate a proxy instance which implements a given interface and delegates its calls to each of a given list of target implementations. The content of the list of targets may be changed during the lifetime of this object, but it's not a good idea to do it while a method is being invoked.

Since:

6 Jul 2011

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
MultiplexInvocationHandler(T[] targets) Constructor.

Method Summary

Modifier and Type	Method and Description
T	createMultiplexer(Class<T> clazz) Returns a new proxy instance which implements the given interface type, and which uses this handler to execute its methods.
T[]	getTargets() Returns the list of delegate implementations.
Object	invoke(Object proxy, Method method, Object[] args) Invokes a method by invoking the same method on each of this handler's target instances.
void	setTargets(T[] targets) Sets the list of delegate implementations.

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiplexInvocationHandler

public MultiplexInvocationHandler(T[] targets)

Constructor.

Parameters:

targets - target instances

Method Detail

setTargets

public void setTargets(T[] targets)

Sets the list of delegate implementations.

Parameters:

targets - target instances

getTargets

public T[] getTargets()

Returns the list of delegate implementations.

Returns:

target instances

invoke

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

Invokes a method by invoking the same method on each of this handler's target instances. If any invocation throws an exception, it is thrown from this method and the method is not invoked on later targets. If the method terminates normally, the return value is the return value of the invocation from the first target.

Specified by:

invoke in interface InvocationHandler

Throws:

Throwable

createMultiplexer

public T createMultiplexer(Class<T> clazz)

Returns a new proxy instance which implements the given interface type, and which uses this handler to execute its methods.

Parameters:

clazz - interface the return value will implement

Returns:

multiplexing proxy instance