org.eclipse.emf.ecp.internal.core.util.observer

Class ECPObserverBusImpl

java.lang.Object

org.eclipse.emf.ecp.internal.core.util.observer.ECPObserverBusImpl

All Implemented Interfaces:

ECPObserverBus

public class ECPObserverBusImpl
extends Object
implements ECPObserverBus

This is a universal observer bus. This class follows the publish/subscribe pattern, it is a central dispatcher for observers and makes use of generics in order to allow type safety. It can be used as singleton or be injected through DI. Observers have to implement the ECPObserver interface, which is only used as a marker. Future use of Annotations is possible. by using notify(Class) (e.g. bus.notify(MyObserver.class).myObserverMethod()) all registered Observers are notified. This is implemented by using the java Proxy class. By calling notify(Class) a proxy is returned, which then calls all registered observers. The proxy can also be casted into ECPObserverCall, which allows to access all results by the different observers. Example code:

 // A is ESObserver
 A a = new A() {

        public void foo() {
                System.out.println("A says: go!");
        }
 };

 // B extends A and is IObserver
 B b = new B() {

        public void say(String ja) {
                System.out.println("B says: " + ja);
        }

        public void foo() {
                System.out.println("B says: h??");
        }
 };

 // B is registered first
 ObserverBus.register(b);
 ObserverBus.register(a);

 ObserverBus.notify(A.class).foo();

 ObserverBus.notify(B.class).say("w00t");

 // Output:

 // B says: h??
 // A says: go!
 //
 // B says: w00t

 

Author:

wesendon

Constructor Summary

Constructors

Constructor and Description
ECPObserverBusImpl() Default constructor.

Method Summary

Modifier and Type	Method and Description
<T extends ECPObserver> T	notify(Class<T> clazz) This method allows you to notify all observers.
<T extends ECPObserver> T	notify(Class<T> clazz, boolean prioritized) This method allows you to notify all observers.
void	register(ECPObserver observer) Registers an observer for all observer interfaces implemented by the object or its super classes.
void	register(ECPObserver observer, Class<? extends ECPObserver>... classes) Registers an observer for the specified observer interfaces.
void	unregister(ECPObserver observer) Unregisters an observer for all observer interfaces implemented by the object or its super classes.
void	unregister(ECPObserver observer, Class<? extends ECPObserver>... classes) Unregisters an observer for the specified observer interfaces.

Methods inherited from class java.lang.Object

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

Constructor Detail

ECPObserverBusImpl

public ECPObserverBusImpl()

Default constructor.

Method Detail

notify

public <T extends ECPObserver> T notify(Class<T> clazz)

This method allows you to notify all observers.

Specified by:

notify in interface ECPObserverBus

Type Parameters:

T - class of observer

Parameters:

clazz - class of observer

Returns:

call object

notify

public <T extends ECPObserver> T notify(Class<T> clazz,
                                        boolean prioritized)

This method allows you to notify all observers.

Type Parameters:

T - class of observer

Parameters:

clazz - class of observer

prioritized - sort observer after ECPPrioritizedIObserver

Returns:

call object

register

public void register(ECPObserver observer)

Registers an observer for all observer interfaces implemented by the object or its super classes.

Specified by:

register in interface ECPObserverBus

Parameters:

observer - observer object

register

public void register(ECPObserver observer,
                     Class<? extends ECPObserver>... classes)

Registers an observer for the specified observer interfaces.

Parameters:

observer - observer object

classes - set of classes

unregister

public void unregister(ECPObserver observer)

Unregisters an observer for all observer interfaces implemented by the object or its super classes.

Specified by:

unregister in interface ECPObserverBus

Parameters:

observer - observer object

unregister

public void unregister(ECPObserver observer,
                       Class<? extends ECPObserver>... classes)

Unregisters an observer for the specified observer interfaces.

Parameters:

observer - observer object

classes - set of classes