io.vertx.core.streams

Interface Pump

public interface Pump

Pumps data from a ReadStream to a WriteStream and performs flow control where necessary to prevent the write stream buffer from getting overfull.

Instances of this class read items from a ReadStream and write them to a WriteStream. If data can be read faster than it can be written this could result in the write queue of the WriteStream growing without bound, eventually causing it to exhaust all available RAM.

To prevent this, after each write, instances of this class check whether the write queue of the WriteStream is full, and if so, the ReadStream is paused, and a drainHandler is set on the WriteStream.

When the WriteStream has processed half of its backlog, the drainHandler will be called, which results in the pump resuming the ReadStream.

This class can be used to pump from any ReadStream to any WriteStream, e.g. from an HttpServerRequest to an AsyncFile, or from NetSocket to a WebSocket.

Please see the documentation for more information.

Author:

Tim Fox

Method Summary

Modifier and Type	Method and Description
int	numberPumped() Return the total number of items pumped by this pump.
static <T> Pump	pump(ReadStream<T> rs, WriteStream<T> ws) Create a new Pump with the given ReadStream and WriteStream
static <T> Pump	pump(ReadStream<T> rs, WriteStream<T> ws, int writeQueueMaxSize) Create a new Pump with the given ReadStream and WriteStream and writeQueueMaxSize
Pump	setWriteQueueMaxSize(int maxSize) Set the write queue max size to maxSize
Pump	start() Start the Pump.
Pump	stop() Stop the Pump.

Method Detail

pump

static <T> Pump pump(ReadStream<T> rs,
                     WriteStream<T> ws)

Create a new Pump with the given ReadStream and WriteStream

Parameters:

rs - the read stream

ws - the write stream

Returns:

the pump

pump

static <T> Pump pump(ReadStream<T> rs,
                     WriteStream<T> ws,
                     int writeQueueMaxSize)

Create a new Pump with the given ReadStream and WriteStream and writeQueueMaxSize

Parameters:

rs - the read stream

ws - the write stream

writeQueueMaxSize - the max size of the write queue

Returns:

the pump

setWriteQueueMaxSize

Pump setWriteQueueMaxSize(int maxSize)

Set the write queue max size to maxSize

Parameters:

maxSize - the max size

Returns:

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

start

Pump start()

Start the Pump. The Pump can be started and stopped multiple times.

Returns:

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

stop

Pump stop()

Stop the Pump. The Pump can be started and stopped multiple times.

Returns:

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

numberPumped

int numberPumped()

Return the total number of items pumped by this pump.