Package com.google.api.gax.rpc

Class BidiStream<RequestT,​ResponseT>

  • Type Parameters:
    RequestT - The type of each request.
    ResponseT - The type of each response.
    All Implemented Interfaces:
    ClientStream<RequestT>, java.lang.Iterable<ResponseT>
    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

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void closeSend()
      Closes the sending side of the stream.
      void closeSendWithError​(java.lang.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 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

      • 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>

      • closeSendWithError

        public void closeSendWithError​(java.lang.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>