com.tangosol.util.fsm

Class NonBlockingFiniteStateMachine.CoalescedEvent<S extends Enum<S>>

java.lang.Object

com.tangosol.util.fsm.NonBlockingFiniteStateMachine.CoalescedEvent<S>

Type Parameters:

S - the type of the state for the FiniteStateMachine

All Implemented Interfaces:

Event<S>, LifecycleAwareEvent<S>

Enclosing class:

NonBlockingFiniteStateMachine<S extends Enum<S>>

public static class NonBlockingFiniteStateMachine.CoalescedEvent<S extends Enum<S>>
extends Object
implements LifecycleAwareEvent<S>

A NonBlockingFiniteStateMachine.CoalescedEvent is a LifecycleAwareEvent that coalesces other (wrapped) Events with the same discriminator so that only one Event actually executes.

For example: Given 10 Events submitted to a NonBlockingFiniteStateMachine with the same discriminator, only one of the said Events will be processed. All others will be discarded. Once the NonBlockingFiniteStateMachine.CoalescedEvent has been processed, a new batch may be created when another NonBlockingFiniteStateMachine.CoalescedEvent of the same discriminator is submitted.

The actual Event processed depends on the mode of coalescing required. The first NonBlockingFiniteStateMachine.CoalescedEvent submitted to a NonBlockingFiniteStateMachine for a specific discriminator effectively starts the coalescing of Events for the said discriminator. When the mode is set to Process#FIRST, then the first Event (starting the coalescing) will be processed and others will be discarded. When the mode is set of Process#MOST_RECENT then the most recently submitted Event will be processed and likewise, all others for the same discriminator will be discarded.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	NonBlockingFiniteStateMachine.CoalescedEvent.Discriminator A NonBlockingFiniteStateMachine.CoalescedEvent.Discriminator is an object that is used to uniquely differentiate events to be coalesced, scoped by a NonBlockingFiniteStateMachine.
static class	NonBlockingFiniteStateMachine.CoalescedEvent.Process The NonBlockingFiniteStateMachine.CoalescedEvent to process.

Constructor Summary

Constructors

Constructor and Description
CoalescedEvent(Event<S> event) Constructs a NonBlockingFiniteStateMachine.CoalescedEvent of the specified Event type using Process#FIRST.
CoalescedEvent(Event<S> event, NonBlockingFiniteStateMachine.CoalescedEvent.Process mode) Constructs a NonBlockingFiniteStateMachine.CoalescedEvent of the specified Event type.
CoalescedEvent(Event<S> event, NonBlockingFiniteStateMachine.CoalescedEvent.Process mode, Object discriminator) Constructs a NonBlockingFiniteStateMachine.CoalescedEvent with the specified discriminator and Event.

Method Summary

Modifier and Type	Method and Description
S	getDesiredState(S state, ExecutionContext context) Determines the desired state of the FiniteStateMachine for the Event given the current state of the FiniteStateMachine.
boolean	onAccept(ExecutionContext context) Called by a FiniteStateMachine when the LifecycleAwareEvent is initially about to be accepted for processing.
void	onProcessed(ExecutionContext context) Called by a FiniteStateMachine when the LifecycleAwareEvent has been processed.
void	onProcessing(ExecutionContext context) Called by a FiniteStateMachine when the LifecycleAwareEvent is about to be processed.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

CoalescedEvent

public CoalescedEvent(Event<S> event)

Constructs a NonBlockingFiniteStateMachine.CoalescedEvent of the specified Event type using Process#FIRST.

Parameters:

event - the Event to be executed when coalesced

CoalescedEvent

public CoalescedEvent(Event<S> event,
                      NonBlockingFiniteStateMachine.CoalescedEvent.Process mode)

Constructs a NonBlockingFiniteStateMachine.CoalescedEvent of the specified Event type.

Parameters:

event - the Event to be coalesced

mode - which NonBlockingFiniteStateMachine.CoalescedEvents to process

CoalescedEvent

public CoalescedEvent(Event<S> event,
                      NonBlockingFiniteStateMachine.CoalescedEvent.Process mode,
                      Object discriminator)

Constructs a NonBlockingFiniteStateMachine.CoalescedEvent with the specified discriminator and Event.

Parameters:

event - the Event to be coalesced

mode - which NonBlockingFiniteStateMachine.CoalescedEvents to process

discriminator - the descriminator used to uniquely coalesce the Event

Method Detail

getDesiredState

public S getDesiredState(S state,
                         ExecutionContext context)

Determines the desired state of the FiniteStateMachine for the Event given the current state of the FiniteStateMachine.

Specified by:

getDesiredState in interface Event<S extends Enum<S>>

Parameters:

state - the current state of the FiniteStateMachine

context - the ExecutionContext for the Event

Returns:

the desired state of the FiniteStateMachine or null if no transition is required

onAccept

public boolean onAccept(ExecutionContext context)

Called by a FiniteStateMachine when the LifecycleAwareEvent is initially about to be accepted for processing.

Specified by:

onAccept in interface LifecycleAwareEvent<S extends Enum<S>>

Parameters:

context - the ExecutionContext for the Event

Returns:

true if the Event should be accepted, or false if the FiniteStateMachine should ignore the LifecycleAwareEvent

onProcessed

public void onProcessed(ExecutionContext context)

Called by a FiniteStateMachine when the LifecycleAwareEvent has been processed.

Specified by:

onProcessed in interface LifecycleAwareEvent<S extends Enum<S>>

Parameters:

context - the ExecutionContext for the Event

onProcessing

public void onProcessing(ExecutionContext context)

Called by a FiniteStateMachine when the LifecycleAwareEvent is about to be processed.

Specified by:

onProcessing in interface LifecycleAwareEvent<S extends Enum<S>>

Parameters:

context - the ExecutionContext for the Event

toString

public String toString()

Overrides:

toString in class Object