org.wso2.siddhi.core.stream.output.sink.distributed

Class DistributionStrategy

java.lang.Object

org.wso2.siddhi.core.stream.output.sink.distributed.DistributionStrategy

Direct Known Subclasses:

BroadcastDistributionStrategy, PartitionedDistributionStrategy, RoundRobinDistributionStrategy

public abstract class DistributionStrategy
extends Object

Parent class for the Distributed publishing strategy extensions. Note that destinationId of the each destination is implied by the order which @destination annotations appear in @sink annotation. Therefore, when implementing a strategy, if the implementation wants refer to a certain @destination the ID can be derived by looking at the listing order of @destination

Constructor Summary

Constructors

Constructor and Description
DistributionStrategy()

Method Summary

Modifier and Type	Method and Description
void	destinationAvailable(Integer destinationId) Remove a destination to available set of destination IDs.
void	destinationFailed(Integer destinationId) Remove a given destination from available set of destination IDs.
int	getActiveDestinationCount() Get the active number of destinations
abstract List<Integer>	getDestinationsToPublish(Object payload, DynamicOptions transportOptions) This method tells the ID(s) of the destination(s) to which a given messages should be sent.
abstract void	init(org.wso2.siddhi.query.api.definition.StreamDefinition streamDefinition, OptionHolder transportOptionHolder, OptionHolder distributionOptionHolder, List<OptionHolder> destinationOptionHolders, ConfigReader configReader) Initialize the Distribution strategy with the information it will require to make decisions.

Methods inherited from class java.lang.Object

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

Constructor Detail

DistributionStrategy

public DistributionStrategy()

Method Detail

init

public abstract void init(org.wso2.siddhi.query.api.definition.StreamDefinition streamDefinition,
                          OptionHolder transportOptionHolder,
                          OptionHolder distributionOptionHolder,
                          List<OptionHolder> destinationOptionHolders,
                          ConfigReader configReader)

Initialize the Distribution strategy with the information it will require to make decisions.

Parameters:

streamDefinition - The stream attached to the sink this DistributionStrategy is used in

transportOptionHolder - Sink options of the sink which uses this DistributionStrategy

distributionOptionHolder - The option under @destination of the relevant sink.

destinationOptionHolders - The list of options under @destination of the relevant sink.

configReader - This hold the DistributionStrategy extensions configuration reader.

getDestinationsToPublish

public abstract List<Integer> getDestinationsToPublish(Object payload,
                                                       DynamicOptions transportOptions)

This method tells the ID(s) of the destination(s) to which a given messages should be sent. There can be cases where a given message is only sent to a specific destination(e.g., partition based) and message is sent to multiple endpoints(e.g., broadcast)

Parameters:

payload - payload of the message

transportOptions - Dynamic transport options of the sink

Returns:

Set of IDs of the destination to which the event should be sent

destinationFailed

public void destinationFailed(Integer destinationId)

Remove a given destination from available set of destination IDs. Once this method is called for a given destination ID, that particular destination ID will not included in the return value of subsequent getDestinationsToPublish() is calls

Parameters:

destinationId - the ID of the destination to be removed

destinationAvailable

public void destinationAvailable(Integer destinationId)

Remove a destination to available set of destination IDs. Once this method is called for a given destination ID, that particular destination ID will be considered when getDestinationsToPublish() is called

Parameters:

destinationId - the ID of the destination to be check for availability.

getActiveDestinationCount

public int getActiveDestinationCount()

Get the active number of destinations

Returns:

The active number of destinations