org.jboss.aerogear.unifiedpush.message.serviceHolder

Class AbstractServiceHolder<T>

java.lang.Object

org.jboss.aerogear.unifiedpush.message.serviceHolder.AbstractServiceHolder<T>

Type Parameters:

T - the type of the service

Direct Known Subclasses:

ApnsServiceHolder

public abstract class AbstractServiceHolder<T>
extends Object

Holds instances of given service <T> and allows their instantiation, reuse and disposal. Leverages JMS queue to store number of messages corresponding to limit of how many services can be created for given push network. The message is borrowed from this queue when new service is created.The message is returned to this queue when service is destroyed. That ensures that there won't be created more service instances in entire cluster of servers than given limit.

Constructor Summary

Constructors

Constructor and Description
AbstractServiceHolder(int instanceLimit, long instanceAcquiringTimeoutInMillis, long serviceDisposalDelayInMillis) Creates new service instance

Method Summary

Modifier and Type	Method and Description
protected Object	borrowServiceSlotFromQueue(String pushMessageInformationId, String variantID)
T	dequeue(String pushMessageInformationId, String variantID) Dequeues the service instance if there is one available, otherwise returns null
T	dequeueOrCreateNewService(String pushMessageInformationId, String variantID, ServiceConstructor<T> constructor) Holder returns a service for given parameters or uses service constructor to instantiate new service.
void	destroy(String pushMessageInformationId, String variantID)
void	freeUpSlot(String pushMessageInformationId, String variantID) Allows to free up a counter of created services and thus allowing waiting consumers to create new services within the limits.
abstract javax.jms.Queue	getFreeServiceSlotQueue() Returns the Queue used as a counter of free services.
void	initialize(String pushMessageInformationId, String variantID)
void	queueFreedUpService(String pushMessageInformationId, String variantID, T service, ServiceDestroyer<T> destroyer) Allows to queue used and freed up service into cache so that can be reused by another consumer.
protected void	returnServiceSlotToQueue(String pushMessageInformationId, String variantID)

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractServiceHolder

public AbstractServiceHolder(int instanceLimit,
                             long instanceAcquiringTimeoutInMillis,
                             long serviceDisposalDelayInMillis)

Creates new service instance

Parameters:

instanceLimit - how many instances can be created

instanceAcquiringTimeoutInMillis - what is a timeout before the holder can return null

serviceDisposalDelayInMillis - how long the service instance will be held until it is disposed for inactivity

Method Detail

getFreeServiceSlotQueue

public abstract javax.jms.Queue getFreeServiceSlotQueue()

Returns the Queue used as a counter of free services. This queue is populated with number of messages corresponding to limit of how many services can be created for given push network. The message is borrowed from this queue when new service is created. The message is returned to this queue when service is destroyed. That ensures that there won't be created more service instances in entire cluster of servers than given limit.

Returns:

the Queue used as a counter of free services.

initialize

public void initialize(String pushMessageInformationId,
                       String variantID)

destroy

public void destroy(String pushMessageInformationId,
                    String variantID)

dequeueOrCreateNewService

public T dequeueOrCreateNewService(String pushMessageInformationId,
                                   String variantID,
                                   ServiceConstructor<T> constructor)

Holder returns a service for given parameters or uses service constructor to instantiate new service. Number of created or queued services is limited up to configured instanceLimit. The service blocks until a service is available or configured instanceAcquiringTimeoutInMillis. In case the service is not available when times out, holder returns null.

Parameters:

pushMessageInformationId - the push message id

variantID - the variant

constructor - the service constructor

Returns:

the service instance; or null in case too much services were created and no services are queued for reuse

dequeue

public T dequeue(String pushMessageInformationId,
                 String variantID)

Dequeues the service instance if there is one available, otherwise returns null

Parameters:

pushMessageInformationId - the push message id

variantID - the variant

Returns:

the service instance or null if no instance is queued

queueFreedUpService

public void queueFreedUpService(String pushMessageInformationId,
                                String variantID,
                                T service,
                                ServiceDestroyer<T> destroyer)

Allows to queue used and freed up service into cache so that can be reused by another consumer.

Parameters:

pushMessageInformationId - the push message

variantID - the variant

service - the used and freed up service

destroyer - the instance of ServiceDestroyer used to destroy service instance

freeUpSlot

public void freeUpSlot(String pushMessageInformationId,
                       String variantID)

Allows to free up a counter of created services and thus allowing waiting consumers to create new services within the limits. Freed up service is a service that died, disconnected or similar and can no longer be used.

Parameters:

pushMessageInformationId - the push message

variantID - the variant

borrowServiceSlotFromQueue

protected Object borrowServiceSlotFromQueue(String pushMessageInformationId,
                                            String variantID)

returnServiceSlotToQueue

protected void returnServiceSlotToQueue(String pushMessageInformationId,
                                        String variantID)