Package com.reallifedeveloper.common.domain.event

Class SimpleDomainEventPublisher

java.lang.Object

com.reallifedeveloper.common.domain.event.SimpleDomainEventPublisher

All Implemented Interfaces:

DomainEventPublisher

public final class SimpleDomainEventPublisher
extends Object
implements DomainEventPublisher

A publisher of domain events that holds subscribers in a list. Publishing is handled synchronously; to handle events asynchronously, a subscriber could send a message to a message queue or store the event for later processing.

The idea behind this publisher is that it will be configured once and for all, for example using Spring:

   <bean class="th.co.edge.domain.event.SimpleDomainEventPublisher">
     <constructor-arg>
       <list>
         <bean class="com.foo.FooSubscriber" />
         <bean class="com.foo.BarSubscriber" />
       </list>
     </constructor-arg>
   </bean>
 

The publisher can then be injected in the classes that need to publish events:

   @Autowired
   private DomainEventSubscriber eventSubscriber;
 

Used this way in a normal enterprise application, several threads may call the publish(DomainEvent) method simultaneously, so the subscribers should be thread safe.

Author:

RealLifeDeveloper

Constructor Summary

Constructors

Constructor	Description
SimpleDomainEventPublisher()	Creates a new SimpleDomainEventPublisher with no subscribers registered.
SimpleDomainEventPublisher(List<DomainEventSubscriber<? extends DomainEvent>> subscribers)	Creates a new SimpleDomainEventPublisher with a number of subscribers registered to be notified when events are published.

Method Summary

Modifier and Type	Method	Description
void	publish(DomainEvent event)	Publishes a domain event, i.e., calls the DomainEventSubscriber.handleEvent(DomainEvent) method for each registered subscriber.
void	subscribe(DomainEventSubscriber<? extends DomainEvent> subscriber)	Registers an event handler with this publisher.

Methods inherited from class java.lang.Object

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

Constructor Details

SimpleDomainEventPublisher

public SimpleDomainEventPublisher()

Creates a new SimpleDomainEventPublisher with no subscribers registered.

Use the subscribe(DomainEventSubscriber) to add subscribers.

SimpleDomainEventPublisher

public SimpleDomainEventPublisher(List<DomainEventSubscriber<? extends DomainEvent>> subscribers)

Creates a new SimpleDomainEventPublisher with a number of subscribers registered to be notified when events are published.

Parameters:

subscribers - a list of subscribers to notify when events are published

Throws:

IllegalArgumentException - if subscribers is null

Method Details

publish

public void publish(DomainEvent event)

Publishes a domain event, i.e., calls the DomainEventSubscriber.handleEvent(DomainEvent) method for each registered subscriber.

Specified by:

publish in interface DomainEventPublisher

Parameters:

event - the domain event to publish

Throws:

IllegalArgumentException - if event is null

subscribe

public void subscribe(DomainEventSubscriber<? extends DomainEvent> subscriber)

Registers an event handler with this publisher.

Specified by:

subscribe in interface DomainEventPublisher

Parameters:

subscriber - the event handler to register

Throws:

IllegalArgumentException - if subscriber is null