Package io.vertx.core.streams

Interface WriteStream<T>

All Superinterfaces:

StreamBase

All Known Subinterfaces:

AmqpSender, AsyncFile, BodyStream<T>, ClientWebSocket, GrpcClientRequest<Req,Resp>, GrpcServerResponse<Req,Resp>, GrpcWriteStream<T>, HttpClientRequest, HttpServerResponse, KafkaProducer<K,V>, KafkaWriteStream<K,V>, NetSocket, ReactiveWriteStream<T>, ServerWebSocket, SockJSSocket, WebSocket, WebSocketBase

public interface WriteStream<T>
extends StreamBase

Represents a stream of data that can be written to.

Any class that implements this interface can be used by a Pipe to pipe data from a ReadStream to it.

Author:

Tim Fox

Method Summary

Modifier and Type	Method	Description
WriteStream<T>	drainHandler(Handler<Void> handler)	Set a drain handler on the stream.
Future<Void>	end()	Ends the stream.
default Future<Void>	end(T data)	Same as end() but writes some data to the stream before ending.
WriteStream<T>	exceptionHandler(Handler<Throwable> handler)	Set an exception handler on the write stream.
WriteStream<T>	setWriteQueueMaxSize(int maxSize)	Set the maximum size of the write queue to maxSize.
Future<Void>	write(T data)	Write some data to the stream.
boolean	writeQueueFull()	This will return true if there are more bytes in the write queue than the value set using setWriteQueueMaxSize(int)

Method Detail

exceptionHandler

WriteStream<T> exceptionHandler(Handler<Throwable> handler)

Set an exception handler on the write stream.

Specified by:

exceptionHandler in interface StreamBase

Parameters:

handler - the exception handler

Returns:

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

write

Future<Void> write(T data)

Write some data to the stream.

The data is usually put on an internal write queue, and the write actually happens asynchronously. To avoid running out of memory by putting too much on the write queue, check the writeQueueFull() method before writing. This is done automatically if using a Pipe.

When the data is moved from the queue to the actual medium, the returned Future will be completed with the write result, e.g the future is succeeded when a server HTTP response buffer is written to the socket and failed if the remote client has closed the socket while the data was still pending for write.

Parameters:

data - the data to write

Returns:

a future completed with the write result

end

Future<Void> end()

Ends the stream.

Once the stream has ended, it cannot be used any more.

Returns:

a future completed with the result

end

default Future<Void> end(T data)

Same as end() but writes some data to the stream before ending.

Parameters:

data - the data to write

Returns:

a future completed with the result

setWriteQueueMaxSize

WriteStream<T> setWriteQueueMaxSize(int maxSize)

Set the maximum size of the write queue to maxSize. You will still be able to write to the stream even if there is more than maxSize items in the write queue. This is used as an indicator by classes such as Pipe to provide flow control.

The value is defined by the implementation of the stream, e.g in bytes for a NetSocket, etc...

Parameters:

maxSize - the max size of the write stream

Returns:

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

writeQueueFull

boolean writeQueueFull()

This will return true if there are more bytes in the write queue than the value set using setWriteQueueMaxSize(int)

Returns:

true if write queue is full

drainHandler

WriteStream<T> drainHandler(Handler<Void> handler)

Set a drain handler on the stream. If the write queue is full, then the handler will be called when the write queue is ready to accept buffers again. See Pipe for an example of this being used.

The stream implementation defines when the drain handler, for example it could be when the queue size has been reduced to maxSize / 2.

Parameters:

handler - the handler

Returns:

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