com.linecorp.armeria.common.stream

Interface StreamMessageDuplicator<T>

Type Parameters:

T - the type of elements

All Superinterfaces:

AutoCloseable, SafeCloseable

All Known Subinterfaces:

HttpRequestDuplicator, HttpResponseDuplicator

All Known Implementing Classes:

DefaultStreamMessageDuplicator

public interface StreamMessageDuplicator<T>
extends SafeCloseable

A duplicator that duplicates a StreamMessage into one or more StreamMessages, which publish the same elements.

Only one subscriber can subscribe to a StreamMessage. If you want to subscribe to it multiple times, use StreamMessageDuplicator which is returned by calling StreamMessage.toDuplicator().

 StreamMessage<String> streamMessage = ...
 try (StreamMessageDuplicator<String> duplicator = streamMessage.toDuplicator()) {
     // streamMessage.subscribe(...) will throw an exception. You cannot subscribe to streamMessage anymore.

     // Duplicate the stream as many as you want to subscribe.
     StreamMessage<String> duplicatedStreamMessage1 = duplicator.duplicate();
     StreamMessage<String> duplicatedStreamMessage2 = duplicator.duplicate();

     duplicatedStreamMessage1.subscribe(...);
     duplicatedStreamMessage2.subscribe(...);
 }
 

Use the try-with-resources block or call close() manually to clean up the resources after all subscriptions are done. If you want to stop publishing and clean up the resources immediately, call abort(). If you do none of these, memory leak might happen.

If you subscribe to the duplicated stream message with the SubscriptionOption.WITH_POOLED_OBJECTS, the published elements can be shared across Subscribers. So do not manipulate the data unless you copy them.

Method Summary

Modifier and Type	Method and Description
void	abort() Closes this duplicator and aborts all stream messages returned by duplicate().
void	abort(Throwable cause) Closes this duplicator and aborts all stream messages returned by duplicate() with the specified Throwable.
void	close() Closes this duplicator and prevents it from further duplication.
StreamMessage<T>	duplicate() Returns a new StreamMessage that publishes the same elements as the StreamMessage that this duplicator is created from.

Method Detail

duplicate

StreamMessage<T> duplicate()

Returns a new StreamMessage that publishes the same elements as the StreamMessage that this duplicator is created from.

close

void close()

Closes this duplicator and prevents it from further duplication. duplicate() will raise an IllegalStateException after this method is invoked.

Note that the previously duplicated streams will not be closed but will continue publishing data until the original StreamMessage is closed. All the data published from the original StreamMessage are cleaned up when all duplicated streams are complete. If you want to stop publishing and clean up the resources immediately, call abort().

Specified by:

close in interface AutoCloseable

Specified by:

close in interface SafeCloseable

abort

void abort()

Closes this duplicator and aborts all stream messages returned by duplicate(). This will also clean up the data published from the original StreamMessage.

abort

void abort(Throwable cause)

Closes this duplicator and aborts all stream messages returned by duplicate() with the specified Throwable. This will also clean up the data published from the original StreamMessage.