com.cookingfox.lapasse.impl.message.bus

Class AbstractMessageBus<M extends Message,H extends MessageHandler<M>>

java.lang.Object

com.cookingfox.lapasse.impl.message.bus.AbstractMessageBus<M,H>

Type Parameters:

M - The concrete message type.

H - The concrete message handler type.

All Implemented Interfaces:

Disposable, MessageBus<M,H>

Direct Known Subclasses:

DefaultCommandBus, DefaultEventBus

public abstract class AbstractMessageBus<M extends Message,H extends MessageHandler<M>>
extends Object
implements MessageBus<M,H>

Abstract message bus implementation.

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<Class<M>,Set<H>>	messageHandlerMap A map of message types to a set of message handlers.
protected MessageStore	messageStore Stores messages.
protected OnMessageAdded	onMessageAddedToStore Listener for when a new message is added to the store.

Constructor Summary

Constructors

Constructor and Description
AbstractMessageBus(MessageStore messageStore)

Method Summary

Modifier and Type	Method and Description
void	dispose() Hook for cleaning up: remove listeners, shutdown threads, etc.
protected abstract void	executeHandler(M message, H messageHandler) Actually execute the message handler for this message.
protected Set<H>	getMessageHandlers(Class<? extends Message> messageClass) Get mapped handlers for this message class.
void	handleMessage(M message) Execute the message handler that is mapped to this message type.
void	mapMessageHandler(Class<M> messageClass, H messageHandler) Map a message handler for a concrete message type.
protected abstract boolean	shouldHandleMessageType(Message message) Returns whether this message bus implementation should handle the concrete message object.

Methods inherited from class java.lang.Object

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

Field Detail

messageHandlerMap

protected final Map<Class<M extends Message>,Set<H extends MessageHandler<M>>> messageHandlerMap

A map of message types to a set of message handlers.

messageStore

protected final MessageStore messageStore

Stores messages.

onMessageAddedToStore

protected final OnMessageAdded onMessageAddedToStore

Listener for when a new message is added to the store.

Constructor Detail

AbstractMessageBus

public AbstractMessageBus(MessageStore messageStore)

Method Detail

dispose

public void dispose()

Description copied from interface: Disposable

Hook for cleaning up: remove listeners, shutdown threads, etc.

Specified by:

dispose in interface Disposable

handleMessage

public void handleMessage(M message)

Description copied from interface: MessageBus

Execute the message handler that is mapped to this message type. Throws if no handler is mapped yet.

Specified by:

handleMessage in interface MessageBus<M extends Message,H extends MessageHandler<M>>

Parameters:

message - The message to handle.

See Also:

MessageBus.mapMessageHandler(Class, MessageHandler)

mapMessageHandler

public void mapMessageHandler(Class<M> messageClass,
                              H messageHandler)

Description copied from interface: MessageBus

Map a message handler for a concrete message type.

Specified by:

mapMessageHandler in interface MessageBus<M extends Message,H extends MessageHandler<M>>

Parameters:

messageClass - The concrete message type.

messageHandler - The handler that is executed when MessageBus.handleMessage(Message) is called.

executeHandler

protected abstract void executeHandler(M message,
                                       H messageHandler)

Actually execute the message handler for this message.

Parameters:

message - The message to handle.

messageHandler - The message handler that is associated with this message.

shouldHandleMessageType

protected abstract boolean shouldHandleMessageType(Message message)

Returns whether this message bus implementation should handle the concrete message object. Typically this returns the result of an `instanceof` check for the concrete message type `M`.

Parameters:

message - The concrete message object.

Returns:

Whether the message should be handled by this message bus.

See Also:

M

getMessageHandlers

protected Set<H> getMessageHandlers(Class<? extends Message> messageClass)

Get mapped handlers for this message class.

Parameters:

messageClass - The message class to get handlers for.

Returns:

The handlers for this message class.

Throws:

NoMessageHandlersException - when no handlers are mapped for this message.