Module it.rebirthproject.ufoeb

Package it.rebirthproject.ufoeb.architecture.eventbus

Class EventBusInfrastructure

java.lang.Object

it.rebirthproject.ufoeb.architecture.eventbus.EventBusInfrastructure

final class EventBusInfrastructure
extends Object

The data structures composing the infrastructure of the EventBus.

Field Summary

Fields

Modifier and Type	Field	Description
private final Thread	busMemoryStateManagerThread	A Thread used by the BusMemoryStateManager to work asynchronously.
private final CountDownLatch	countDownLatch	During the shutdown phase the EventBusInfrastructure will send a shutdown message to each EventExecutor's worker and to the BusMemoryStateManager.
private static final org.slf4j.Logger	logger	The logger used by this class.
private final BlockingQueue<Message>	messageQueue	A blocking queue used to communicate internal messages to other EventBus's components.
private final int	numberOfWorkers	The number of workers (EventExecutors) used by the bus behind the scenes to deliver events.
private final ExecutorService	workersPoolExecutor	An ExecutorService used as a thread pool of EventExecutor workers.

Constructor Summary

Constructors

Constructor	Description
EventBusInfrastructure(ListenerMethodFinder listenerMethodFinder, InheritancePolicy inheritancePolicy, int queueLength, int numberOfWorkers, boolean safeRegistrationsListNeeded, boolean throwNoRegistrationsWarning, boolean verboseLogging)	The constructor used to build the EventBusInfrastructure

Method Summary

Modifier and Type	Method	Description
(package private) void	sendMessage(Message message)	The method used to send messages to other internal components
private void	sendShutdownStateManagerMessage()	Private utility method to send a ShutdownStateManagerMessage to the BusMemoryStateManager
(package private) void	shutdown()	The method used to shut down the EventBus.
(package private) void	startup()	The method used to start up the EventBusInfrastructure

Methods inherited from class java.lang.Object

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

Field Details

logger

private static final org.slf4j.Logger logger

The logger used by this class.

workersPoolExecutor

private final ExecutorService workersPoolExecutor

An ExecutorService used as a thread pool of EventExecutor workers.

busMemoryStateManagerThread

private final Thread busMemoryStateManagerThread

A Thread used by the BusMemoryStateManager to work asynchronously.

countDownLatch

private final CountDownLatch countDownLatch

During the shutdown phase the EventBusInfrastructure will send a shutdown message to each EventExecutor's worker and to the BusMemoryStateManager. This CountDownLatch is used to wait until each eventbus component is being shutdown.

messageQueue

private final BlockingQueue<Message> messageQueue

A blocking queue used to communicate internal messages to other EventBus's components.

numberOfWorkers

private final int numberOfWorkers

The number of workers (EventExecutors) used by the bus behind the scenes to deliver events.

Constructor Details

EventBusInfrastructure

EventBusInfrastructure(ListenerMethodFinder listenerMethodFinder,
 InheritancePolicy inheritancePolicy,
 int queueLength,
 int numberOfWorkers,
 boolean safeRegistrationsListNeeded,
 boolean throwNoRegistrationsWarning,
 boolean verboseLogging)

The constructor used to build the EventBusInfrastructure

Parameters:

listenerMethodFinder - The ListenerMethodFinder is a service used to retrieve registered listeners methods annotated with Listen and to store them inside the MemoryState

inheritancePolicy - The event InheritancePolicy used by the bus

numberOfWorkers - The number of workers (EventExecutors) used by the bus behind the scenes to deliver events.

safeRegistrationsListNeeded - is used when you want to use inheritance over a listener and all its superclasses. Enabling it will let the bus look for all listeners' methods considering also all their superclasses methods.

throwNoRegistrationsWarning - A boolean which defines if it's needed to throw warnings when no registrations are found for a specific event

verboseLogging - Boolean parameter set to true if a more verbose logging is needed

See Also:

• EventBusBuilder
• ListenerMethodFinder
• InheritancePolicy

Method Details

startup

void startup()

The method used to start up the EventBusInfrastructure

sendMessage

void sendMessage(Message message)
          throws EventBusException

The method used to send messages to other internal components

Parameters:

message - The command/query message to send to other internal components

Throws:

EventBusException - if something goes wrong sending an internal message

shutdown

void shutdown()

The method used to shut down the EventBus. The EventBusInfrastructure will dispose his data structures and send a message to all the others internal components (like EventExecutors workers and BusMemoryStateManager) in order to shut down.

sendShutdownStateManagerMessage

private void sendShutdownStateManagerMessage()

Private utility method to send a ShutdownStateManagerMessage to the BusMemoryStateManager