com.google.api.gax.rpc

Class BidiStream<RequestT,ResponseT>

java.lang.Object

com.google.api.gax.rpc.ServerStream<ResponseT>

com.google.api.gax.rpc.BidiStream<RequestT,ResponseT>

Type Parameters:

RequestT - The type of each request.

ResponseT - The type of each response.

All Implemented Interfaces:

ClientStream<RequestT>, Iterable<ResponseT>

@BetaApi(value="The surface for streaming is not stable yet and may change in the future.")
public class BidiStream<RequestT,ResponseT>
extends ServerStream<ResponseT>
implements ClientStream<RequestT>

A wrapper around a bidirectional stream.

This class asynchronously pulls responses from upstream via StreamController.request(int) and exposes them via its Iterator. The implementation is back pressure aware and uses a constant buffer of 1 item.

Please note that the stream can only be consumed once and must either be fully consumed or be canceled.

This class can also be used to send requests to the server using send(Object).

Neither this class nor the iterator it returns is thread-safe.

In the example below, we iterate through responses from the server and echo back the items we see:

 BidiStream<Item> stream = ...;

 for (Item item : stream) {
   System.out.println(item.id());

   stream.send(item.id());

   // Allow for early termination
   if (item.id().equals("needle")) {
     // Cancelling the stream will cause `hasNext()` to return false on the next iteration,
     // naturally breaking the loop.
     stream.cancel();
   }
 }
 

Method Summary

Modifier and Type	Method and Description
void	closeSend() Closes the sending side of the stream.
void	closeSendWithError(Throwable t) Closes the sending side of the stream with error.
boolean	isSendReady() Reports whether a message can be sent without requiring excessive buffering internally.
void	send(RequestT req) Send req to the server.

Methods inherited from class com.google.api.gax.rpc.ServerStream

cancel, isReceiveReady, iterator

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

send

public void send(RequestT req)

Send req to the server.

Specified by:

send in interface ClientStream<RequestT>

isSendReady

public boolean isSendReady()

Reports whether a message can be sent without requiring excessive buffering internally.

This method only provides a hint. It is still correct for the user to call send(Object) even when this method returns false.

Specified by:

isSendReady in interface ClientStream<RequestT>

closeSend

public void closeSend()

Closes the sending side of the stream. Once called, no further calls to send(Object), closeSend(), or closeSendWithError(Throwable) are allowed.

Calling this method does not affect the receiving side, the iterator will continue to yield responses from the server.

Specified by:

closeSend in interface ClientStream<RequestT>

closeSendWithError

public void closeSendWithError(Throwable t)

Closes the sending side of the stream with error. The error is propagated to the server. Once called, no further calls to send(Object), closeSend(), or closeSendWithError(Throwable) are allowed.

Calling this method does not affect the receiving side, the iterator will continue to yield responses from the server.

Specified by:

closeSendWithError in interface ClientStream<RequestT>