org.streamingpool.core.service

Interface StreamFactory

All Known Subinterfaces:

TypedStreamFactory<X,T>

All Known Implementing Classes:

AkkaStreamFactory, CombineWithLatestStreamFactory, CompositionStreamFactory, CreatorStreamFactory, DelayedStreamFactory, DerivedStreamFactory, FilteredStreamFactory, OverlapBufferStreamFactory

public interface StreamFactory

This interface represents a factory for Publishers. An implementation of this interface is able to create a stream given an implementation of StreamId and a DiscoveryService. During the creation of a stream it is allowed to discover other streams. This allow the possibility to create streams that merge other streams while performing transformations.

NOTE: it is not allowed to discover other streams using the provided DiscoveryService in multiple threads. In other words, do not use new threads inside the stream creation. The provided DiscoveryService checks that subsequent discoveries are performed on the same thread, otherwise an exception is risen. It is not possible to enforce the single thread execution in the create(StreamId, DiscoveryService) method, but using the DiscoveryService from different threads may lead to unpredictable behavior and can cause deadlocks.

Method Summary

Modifier and Type	Method and Description
<T> ErrorStreamPair<T>	create(StreamId<T> id, DiscoveryService discoveryService) Given an implementation of StreamId and a DiscoveryService this method creates a Publisher.

Method Detail

create

<T> ErrorStreamPair<T> create(StreamId<T> id,
                              DiscoveryService discoveryService)

Given an implementation of StreamId and a DiscoveryService this method creates a Publisher. The provided DiscoveryService can be used to discover other streams that are needed in the creation process (stream combination, transformation, etc.)

NOTE: it is strongly discouraged the use of multiple threads inside this method (see TypedStreamFactory documentation).

Parameters:

id - the id of the stream to create

discoveryService - DiscoveryService which can be used by the factory to look up other streams ('upstream' of the one it will create)

Returns:

the newly created stream or null if this factory cannot create the stream of the given id