io.spine.server.transport

Class Subscriber

java.lang.Object

io.spine.server.transport.AbstractChannel

io.spine.server.transport.Subscriber

All Implemented Interfaces:

MessageChannel, java.lang.AutoCloseable

@SPI
public abstract class Subscriber
extends AbstractChannel

Subscriber for messages of a specific type.

There can be many subscribers per message type.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Subscriber(io.spine.server.transport.ChannelId id)

Method Summary

Modifier and Type	Method and Description
void	addObserver(io.grpc.stub.StreamObserver<io.spine.server.integration.ExternalMessage> observer) Adds an observer to receive the subscription updates.
protected void	callObservers(io.spine.server.integration.ExternalMessage message)
void	close()
boolean	isStale() Allows to understand whether this channel is stale and can be closed.
java.lang.Iterable<io.grpc.stub.StreamObserver<io.spine.server.integration.ExternalMessage>>	observers() Obtains current observers registered in this instance of Subscriber which receive the subscription updates.
void	onMessage(io.spine.server.integration.ExternalMessage message) Passes the given message to observers.
void	removeObserver(io.grpc.stub.StreamObserver<io.spine.server.integration.ExternalMessage> observer) Removes an existing observer and disconnects it from this subscription channel.

Methods inherited from class io.spine.server.transport.AbstractChannel

id

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.spine.server.transport.MessageChannel

channelIdFor, targetType

Constructor Detail

Subscriber

protected Subscriber(io.spine.server.transport.ChannelId id)

Method Detail

observers

public java.lang.Iterable<io.grpc.stub.StreamObserver<io.spine.server.integration.ExternalMessage>> observers()

Obtains current observers registered in this instance of Subscriber which receive the subscription updates.

Returns:

observers for this subscriber

addObserver

public void addObserver(io.grpc.stub.StreamObserver<io.spine.server.integration.ExternalMessage> observer)

Adds an observer to receive the subscription updates.

Parameters:

observer - the observer to register

removeObserver

public void removeObserver(io.grpc.stub.StreamObserver<io.spine.server.integration.ExternalMessage> observer)

Removes an existing observer and disconnects it from this subscription channel.

If the given observer is not registered at the moment, does nothing.

Parameters:

observer - the observer to remove

isStale

public boolean isStale()

Description copied from interface: MessageChannel

Allows to understand whether this channel is stale and can be closed.

Returns:

true if the channel is stale, false otherwise

onMessage

public void onMessage(io.spine.server.integration.ExternalMessage message)

Passes the given message to observers.

Parameters:

message - the subscription update to pass to the observers for this channel

callObservers

protected final void callObservers(io.spine.server.integration.ExternalMessage message)

close

public void close()