org.occurrent.subscription.blocking.durable.catchup

Class CatchupSubscriptionModel

java.lang.Object

org.occurrent.subscription.blocking.durable.catchup.CatchupSubscriptionModel

All Implemented Interfaces:

DelegatingSubscriptionModel, Subscribable, SubscriptionModel, SubscriptionModelLifeCycle

public class CatchupSubscriptionModel
extends Object
implements SubscriptionModel, DelegatingSubscriptionModel

A SubscriptionModel that reads historic cloud events from the all event streams (see EventStoreQueries.all()) until caught up with the PositionAwareSubscriptionModel.globalSubscriptionPosition() of the subscription (you probably want to narrow the historic set events of events by using a Filter when subscribing). It'll automatically switch over to the supplied subscription when all history events are read and the subscription has caught-up.

Note that the implementation uses an in-memory cache (default size is but this can be configured using a CatchupSubscriptionModelConfig) to reduce the number of duplicate event when switching from historic events to the current cloud event position. It's highly recommended that the application logic is idempotent if the cache size doesn't cover all duplicate events.

Also note that the if a the subscription crashes during catch-up mode it'll continue where it left-off on restart, given the no specific `StartAt` position is supplied. For this to work, the subscription must store the subscription position in a SubscriptionPositionStorage implementation periodically. It's possible to configure how often this should happen in the CatchupSubscriptionModelConfig.

Constructor Summary

Constructors

Constructor and Description
CatchupSubscriptionModel(PositionAwareSubscriptionModel subscriptionModel, EventStoreQueries eventStoreQueries) Create a new instance of CatchupSubscriptionModel the uses a default CatchupSubscriptionModelConfig with a cache size of but store the subscription position during the catch-up phase (i.e.
CatchupSubscriptionModel(PositionAwareSubscriptionModel subscriptionModel, EventStoreQueries eventStoreQueries, CatchupSubscriptionModelConfig config) Create a new instance of CatchupSubscriptionModel the uses the supplied CatchupSubscriptionModelConfig.

Method Summary

Modifier and Type	Method and Description
void	cancelSubscription(String subscriptionId)
SubscriptionModel	getDelegatedSubscriptionModel()
boolean	isPaused(String subscriptionId)
boolean	isRunning()
boolean	isRunning(String subscriptionId)
static boolean	isTimeBasedSubscriptionPosition(org.occurrent.subscription.StartAt startAt)
static boolean	isTimeBasedSubscriptionPosition(org.occurrent.subscription.SubscriptionPosition subscriptionPosition)
void	pauseSubscription(String subscriptionId)
Subscription	resumeSubscription(String subscriptionId)
void	shutdown()
void	start()
void	stop()
Subscription	subscribe(String subscriptionId, org.occurrent.subscription.SubscriptionFilter filter, org.occurrent.subscription.StartAt startAt, Consumer<io.cloudevents.CloudEvent> action)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.occurrent.subscription.api.blocking.Subscribable

subscribe, subscribe, subscribe

Methods inherited from interface org.occurrent.subscription.api.blocking.DelegatingSubscriptionModel

getDelegatedSubscriptionModelRecursively

Constructor Detail

CatchupSubscriptionModel

public CatchupSubscriptionModel(PositionAwareSubscriptionModel subscriptionModel,
                                EventStoreQueries eventStoreQueries)

Create a new instance of CatchupSubscriptionModel the uses a default CatchupSubscriptionModelConfig with a cache size of but store the subscription position during the catch-up phase (i.e. if the application crashes or is shutdown during the catch-up phase then the subscription will start from the beginning on application restart). After the catch-up phase has completed, the PositionAwareSubscriptionModel will dictate how often the subscription position is stored.

Parameters:

subscriptionModel - The subscription that'll be used to subscribe to new events after catch-up is completed.

eventStoreQueries - The API that will be used for catch-up

CatchupSubscriptionModel

public CatchupSubscriptionModel(PositionAwareSubscriptionModel subscriptionModel,
                                EventStoreQueries eventStoreQueries,
                                CatchupSubscriptionModelConfig config)

Create a new instance of CatchupSubscriptionModel the uses the supplied CatchupSubscriptionModelConfig. After catch-up mode has completed, the PositionAwareSubscriptionModel will dictate how often the subscription position is stored.

Parameters:

subscriptionModel - The subscription that'll be used to subscribe to new events after catch-up is completed.

eventStoreQueries - The API that will be used for catch-up

config - The configuration to use

Method Detail

subscribe

public Subscription subscribe(String subscriptionId,
                              org.occurrent.subscription.SubscriptionFilter filter,
                              org.occurrent.subscription.StartAt startAt,
                              Consumer<io.cloudevents.CloudEvent> action)

Specified by:

subscribe in interface Subscribable

stop

public void stop()

Specified by:

stop in interface SubscriptionModelLifeCycle

start

public void start()

Specified by:

start in interface SubscriptionModelLifeCycle

isRunning

public boolean isRunning()

Specified by:

isRunning in interface SubscriptionModelLifeCycle

isRunning

public boolean isRunning(String subscriptionId)

Specified by:

isRunning in interface SubscriptionModelLifeCycle

isPaused

public boolean isPaused(String subscriptionId)

Specified by:

isPaused in interface SubscriptionModelLifeCycle

resumeSubscription

public Subscription resumeSubscription(String subscriptionId)

Specified by:

resumeSubscription in interface SubscriptionModelLifeCycle

pauseSubscription

public void pauseSubscription(String subscriptionId)

Specified by:

pauseSubscription in interface SubscriptionModelLifeCycle

cancelSubscription

public void cancelSubscription(String subscriptionId)

Specified by:

cancelSubscription in interface SubscriptionModelLifeCycle

shutdown

@PreDestroy
public void shutdown()

Specified by:

shutdown in interface SubscriptionModelLifeCycle

isTimeBasedSubscriptionPosition

public static boolean isTimeBasedSubscriptionPosition(org.occurrent.subscription.StartAt startAt)

isTimeBasedSubscriptionPosition

public static boolean isTimeBasedSubscriptionPosition(org.occurrent.subscription.SubscriptionPosition subscriptionPosition)

getDelegatedSubscriptionModel

public SubscriptionModel getDelegatedSubscriptionModel()

Specified by:

getDelegatedSubscriptionModel in interface DelegatingSubscriptionModel