com.hammurapi.eventbus
Class AbstractEventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

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java.lang.Object
  com.hammurapi.eventbus.AbstractEventBus<E,P,C,K,H,S>

Type Parameters:

E - Event type.

P - Priority type.

C - Context type.

K - Handler registration key.

All Implemented Interfaces:

EventBus<E,P,C,K,H,S>

Direct Known Subclasses:

LocalEventBusBase

public abstract class AbstractEventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>
extends Object
implements EventBus<E,P,C,K,H,S>

Event bus dispatches events to event handlers.

Nested Class Summary

protected class	AbstractEventBus.CreateMasterHandleResult
static interface	AbstractEventBus.DerivationEx<K> Helper interface for snapshot taking.
static interface	AbstractEventBus.Handle<E,P extends Comparable<P>,C,K> Event handle.
static interface	AbstractEventBus.Snapshot<E,P extends Comparable<P>,C,K,H extends EventBus.Handle<E,P,C>,S extends EventStore<E,P,C,H,S>> Interface to output bus structure for troubleshooting.
static interface	AbstractEventBus.StateSnapshot<E,P extends Comparable<P>,C,K,H extends EventBus.Handle<E,P,C>,S extends EventStore<E,P,C,H,S>> This snapshot also outputs bus state.
static interface	AbstractEventBus.StoreEntry<E,P extends Comparable<P>,C,K> Store entry complements store handle to provide functionality of event handle.

Field Summary

protected static Logger

logger

Constructor Summary

AbstractEventBus(Class<E> eventType, S store, InferencePolicy inferencePolicy, InferenceFilter<E,P,C,K,H,S> inferenceFilter, StatsCollector statsCollector, TimeUnit statsTimeUnit, Matcher<E,P,C,K,H,S> matcher)

Method Summary

K	addHandler(EventHandler<E,P,C,H,S> eventHandler) Registers event handler with a predicate.
protected abstract TrackingExecutorService	createExecutorService(boolean oneOff, String name) Create a wrapper around the root executor service for task tracking purposes.
protected abstract TrackingExecutorService	createExecutorService(ExecutorService master, boolean oneOff, String name) Creates a wrapper around the master executor service for task tracking purposes.
protected abstract InferenceContext<E,P,C,K,H,S>	createInferenceContext() Creates inference context with zero chain length and no root handle.
protected H	createMasterHandle(PostCommand<E,P,C,K,H,S> postCommand) Creates and returns new master handle.
Collection<Derivation<E,P,C>>	getDerivations(E event)
Class<E>	getEventType()
ExceptionHandler	getExceptionHandler()
protected abstract TrackingExecutorService	getExecutorService() Returns "root" executor service to submit predicate evaluation and handler execution tasks to.
InferencePolicy	getInferencePolicy()
protected abstract Lock	getRtcLock()
S	getStore()
void	join()
boolean	join(long timeout)
void	manageHandlers(Matcher.HandlerManager<E,P,C,K,H,S> handlerManager) This method is used for batch live updates of bus handlers.
protected abstract H	newMasterHandle(PostCommand<E,P,C,K,H,S> postCommand) Instantiates master handle.
protected abstract K	nextId() Generates handler ID.
H	post(E event, ... validators) Posts event to the bus.
protected H	processInferenceCommand(InferenceCommand<E,P,C,K,H,S> command)
protected abstract void	processRemoveCommand(RemoveCommand<E,P,C,K,H,S> command)
void	removeHandlers(Iterable<K> keys) Removes registered handler(s).
void	removeHandlers(K... keys) Removes registered handler(s).
void	reset() Clears join collections and handle map.
void	setExceptionHandler(ExceptionHandler exceptionHandler)
void	takeSnapshot(AbstractEventBus.Snapshot<E,P,C,K,H,S> snapshot)
protected void	workingMemorySnapshot(AbstractEventBus.StateSnapshot<E,P,C,K,H,S> snapshot)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.hammurapi.eventbus.EventBus

remove

Field Detail

logger

protected static final Logger logger

Constructor Detail

AbstractEventBus

public AbstractEventBus(Class<E> eventType,
                        S store,
                        InferencePolicy inferencePolicy,
                        InferenceFilter<E,P,C,K,H,S> inferenceFilter,
                        StatsCollector statsCollector,
                        TimeUnit statsTimeUnit,
                        Matcher<E,P,C,K,H,S> matcher)

Method Detail

getEventType

public Class<E> getEventType()

Specified by:

getEventType in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

getInferencePolicy

public InferencePolicy getInferencePolicy()

Specified by:

getInferencePolicy in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

newMasterHandle

protected abstract H newMasterHandle(PostCommand<E,P,C,K,H,S> postCommand)

Instantiates master handle.

Parameters:

event -

Returns:

getExecutorService

protected abstract TrackingExecutorService getExecutorService()

Returns "root" executor service to submit predicate evaluation and handler execution tasks to.

createExecutorService

protected abstract TrackingExecutorService createExecutorService(ExecutorService master,
                                                                 boolean oneOff,
                                                                 String name)

Creates a wrapper around the master executor service for task tracking purposes.

Parameters:

master - Master executor service

Returns:

createExecutorService

protected abstract TrackingExecutorService createExecutorService(boolean oneOff,
                                                                 String name)

Create a wrapper around the root executor service for task tracking purposes.

Returns:

executor service or null for the synchronous mode.

nextId

protected abstract K nextId()

Generates handler ID.

Returns:

workingMemorySnapshot

protected void workingMemorySnapshot(AbstractEventBus.StateSnapshot<E,P,C,K,H,S> snapshot)

takeSnapshot

public void takeSnapshot(AbstractEventBus.Snapshot<E,P,C,K,H,S> snapshot)

setExceptionHandler

public void setExceptionHandler(ExceptionHandler exceptionHandler)

Specified by:

setExceptionHandler in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

getExceptionHandler

public ExceptionHandler getExceptionHandler()

Specified by:

getExceptionHandler in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

addHandler

public K addHandler(EventHandler<E,P,C,H,S> eventHandler)

Description copied from interface: EventBus

Registers event handler with a predicate.

Specified by:

addHandler in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

Parameters:

eventHandler - Event handler.

Returns:

Registration key object.

removeHandlers

public void removeHandlers(Iterable<K> keys)

Description copied from interface: EventBus

Removes registered handler(s).

Specified by:

removeHandlers in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

removeHandlers

public void removeHandlers(K... keys)

Description copied from interface: EventBus

Removes registered handler(s).

Specified by:

removeHandlers in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

getRtcLock

protected abstract Lock getRtcLock()

post

public H post(E event,
              ... validators)

Description copied from interface: EventBus

Posts event to the bus.

Specified by:

post in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

Parameters:

event - Event to dispatch to handlers.

validators - Predicate(s) which are checked when object is retrieved from the event store. If there is more than one predicate, predicates are connected with AND. If validator(s) evaluate to false, the object handle is considered invalid, i.e. object is considered removed from the store. Once validator(s) evaluate to false, they shall always evaluate to false. One of use of validators can be to expire object in the store, i.e. after some time validator returns false and object is cleared from the database. If validators evaluate to false at put time, object is not put to the store and put() returns null. Validators evaluation result is not cached.

Returns:

Event handle or null if validator(s) evaluate to false.

processInferenceCommand

protected H processInferenceCommand(InferenceCommand<E,P,C,K,H,S> command)

Parameters:

command - command to be processed

executorService - Executor service for asynchronous processing

inferenceCommandsQueue - collector of inference commands for further processing.

processRemoveCommand

protected abstract void processRemoveCommand(RemoveCommand<E,P,C,K,H,S> command)

createMasterHandle

protected H createMasterHandle(PostCommand<E,P,C,K,H,S> postCommand)

Creates and returns new master handle. re-dispatch existing event.

Parameters:

event - Event to add to the store.

joinDelegate -

directPost -

validators -

derivation -

Returns:

Master handle for new event, null for existing.

reset

public void reset()

Description copied from interface: EventBus

Clears join collections and handle map.

Specified by:

reset in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

getDerivations

public Collection<Derivation<E,P,C>> getDerivations(E event)

Specified by:

getDerivations in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

Returns:

Derivations for the event.

join

public void join()
          throws InterruptedException

Throws:

InterruptedException

join

public boolean join(long timeout)
             throws InterruptedException

Throws:

InterruptedException

getStore

public S getStore()

Specified by:

getStore in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

Returns:

event store.

manageHandlers

public void manageHandlers(Matcher.HandlerManager<E,P,C,K,H,S> handlerManager)

Description copied from interface: EventBus

This method is used for batch live updates of bus handlers. The method acquires bus write lock, then invokes bus manager's manageBus() method within a lock and then releases the lock. Therefore, event bus structure update is executed as one logical unit.

Specified by:

manageHandlers in interface EventBus<E,P extends Comparable<P>,C,K,H extends AbstractEventBus.Handle<E,P,C,K>,S extends EventStore<E,P,C,H,S>>

createInferenceContext

protected abstract InferenceContext<E,P,C,K,H,S> createInferenceContext()

Creates inference context with zero chain length and no root handle. Inference queue is supplied with AFTER_EVENT, AFTER_ROOT_EVENT and EXCLUSIVE policies. Use this method to create initial/root inference context.

Returns: