io.vertx.rx.java

Class ReadStreamSubscriber<R,J>

java.lang.Object

rx.Subscriber<R>

io.vertx.rx.java.ReadStreamSubscriber<R,J>

All Implemented Interfaces:

ReadStream<J>, StreamBase, Observer<R>, Subscription

public class ReadStreamSubscriber<R,J>
extends Subscriber<R>
implements ReadStream<J>

An RxJava Subscriber that turns an Observable into a ReadStream.

The stream implements the pause() and resume() operation by maintaining a buffer of BUFFER_SIZE elements between the Observable and the ReadStream.

When the subscriber is created it requests 0 elements to activate the subscriber's back-pressure. Setting the handler initially on the ReadStream triggers a request of BUFFER_SIZE elements. When the item buffer is half empty, new elements are requested to fill the buffer back to BUFFER_SIZE elements.

The #endHandler(Handler) is called when the Observable is completed or has failed and no pending elements, emitted before the completion or failure, are still in the buffer, i.e the handler is not called when the stream is paused.

Author:

Julien Viet

Field Summary

Fields

Modifier and Type	Field and Description
static int	BUFFER_SIZE

Constructor Summary

Constructors

Constructor and Description
ReadStreamSubscriber(java.util.function.Function<R,J> adapter, java.util.function.Consumer<Subscriber<R>> doSubscribe)

Method Summary

Modifier and Type	Method and Description
static <R,J> ReadStream<J>	asReadStream(Observable<R> observable, java.util.function.Function<R,J> adapter)
ReadStream<J>	endHandler(Handler<Void> handler) Set an end handler.
ReadStream<J>	exceptionHandler(Handler<Throwable> handler) Set an exception handler on the read stream.
ReadStream<J>	fetch(long amount) Fetch the specified amount of elements.
ReadStream<J>	handler(Handler<J> handler) Set a data handler.
void	onCompleted()
void	onError(Throwable e)
void	onNext(R item)
ReadStream<J>	pause() Pause the ReadStream, it sets the buffer in fetch mode and clears the actual demand.
ReadStream<J>	resume() Resume reading, and sets the buffer in flowing mode.

Methods inherited from class rx.Subscriber

add, isUnsubscribed, onStart, request, setProducer, unsubscribe

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.vertx.core.streams.ReadStream

collect, pipe, pipeTo, pipeTo

Field Detail

BUFFER_SIZE

public static final int BUFFER_SIZE

See Also:

Constant Field Values

Constructor Detail

ReadStreamSubscriber

public ReadStreamSubscriber(java.util.function.Function<R,J> adapter,
                            java.util.function.Consumer<Subscriber<R>> doSubscribe)

Method Detail

asReadStream

public static <R,J> ReadStream<J> asReadStream(Observable<R> observable,
                                               java.util.function.Function<R,J> adapter)

handler

public ReadStream<J> handler(Handler<J> handler)

Description copied from interface: ReadStream

Set a data handler. As data is read, the handler will be called with the data.

Specified by:

handler in interface ReadStream<J>

Returns:

a reference to this, so the API can be used fluently

pause

public ReadStream<J> pause()

Description copied from interface: ReadStream

Pause the ReadStream, it sets the buffer in fetch mode and clears the actual demand.

While it's paused, no data will be sent to the data handler.

Specified by:

pause in interface ReadStream<J>

Returns:

a reference to this, so the API can be used fluently

fetch

public ReadStream<J> fetch(long amount)

Description copied from interface: ReadStream

Fetch the specified amount of elements. If the ReadStream has been paused, reading will recommence with the specified amount of items, otherwise the specified amount will be added to the current stream demand.

Specified by:

fetch in interface ReadStream<J>

Returns:

a reference to this, so the API can be used fluently

resume

public ReadStream<J> resume()

Description copied from interface: ReadStream

Resume reading, and sets the buffer in flowing mode.

If the ReadStream has been paused, reading will recommence on it.

Specified by:

resume in interface ReadStream<J>

Returns:

a reference to this, so the API can be used fluently

endHandler

public ReadStream<J> endHandler(Handler<Void> handler)

Description copied from interface: ReadStream

Set an end handler. Once the stream has ended, and there is no more data to be read, this handler will be called.

Specified by:

endHandler in interface ReadStream<J>

Returns:

a reference to this, so the API can be used fluently

exceptionHandler

public ReadStream<J> exceptionHandler(Handler<Throwable> handler)

Description copied from interface: ReadStream

Set an exception handler on the read stream.

Specified by:

exceptionHandler in interface ReadStream<J>

Specified by:

exceptionHandler in interface StreamBase

Parameters:

handler - the exception handler

Returns:

a reference to this, so the API can be used fluently

onCompleted

public void onCompleted()

Specified by:

onCompleted in interface Observer<R>

onError

public void onError(Throwable e)

Specified by:

onError in interface Observer<R>

onNext

public void onNext(R item)

Specified by:

onNext in interface Observer<R>