io.grpc.stub

Class CallStreamObserver<V>

java.lang.Object

io.grpc.stub.CallStreamObserver<V>

All Implemented Interfaces:

StreamObserver<V>

Direct Known Subclasses:

ClientCallStreamObserver, ServerCallStreamObserver

@ExperimentalApi(value="https://github.com/grpc/grpc-java/issues/1788")
public abstract class CallStreamObserver<V>
extends Object
implements StreamObserver<V>

A refinement of StreamObserver provided by the GRPC runtime to the application that allows for more complex interactions with call behavior.

In any call there are logically two StreamObserver implementations:

• 'inbound' - which the GRPC runtime calls when it receives messages from the remote peer. This is implemented by the application.
• 'outbound' - which the GRPC runtime provides to the application which it uses to send messages to the remote peer.

Implementations of this class represent the 'outbound' message stream.

Constructor Summary

Constructors

Constructor and Description
CallStreamObserver()

Method Summary

Modifier and Type	Method and Description
abstract void	disableAutoInboundFlowControl() Disables automatic flow control where a token is returned to the peer after a call to the 'inbound' StreamObserver.onNext(Object) has completed.
abstract boolean	isReady() If true indicates that a call to StreamObserver.onNext(Object) will not require the entire message to be buffered before it is sent to the peer.
abstract void	request(int count) Requests the peer to produce count more messages to be delivered to the 'inbound' StreamObserver.
abstract void	setMessageCompression(boolean enable) Sets message compression for subsequent calls to StreamObserver.onNext(V).
abstract void	setOnReadyHandler(Runnable onReadyHandler) Set a Runnable that will be executed every time the stream isReady() state changes from false to true.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.grpc.stub.StreamObserver

onCompleted, onError, onNext

Constructor Detail

CallStreamObserver

public CallStreamObserver()

Method Detail

isReady

public abstract boolean isReady()

If true indicates that a call to StreamObserver.onNext(Object) will not require the entire message to be buffered before it is sent to the peer.

setOnReadyHandler

public abstract void setOnReadyHandler(Runnable onReadyHandler)

Set a Runnable that will be executed every time the stream isReady() state changes from false to true. While it is not guaranteed that the same thread will always be used to execute the Runnable, it is guaranteed that executions are serialized with calls to the 'inbound' StreamObserver.

Note that the handler may be called some time after isReady() has transitioned to true as other callbacks may still be executing in the 'inbound' observer.

Parameters:

onReadyHandler - to call when peer is ready to receive more messages.

disableAutoInboundFlowControl

public abstract void disableAutoInboundFlowControl()

Disables automatic flow control where a token is returned to the peer after a call to the 'inbound' StreamObserver.onNext(Object) has completed. If disabled an application must make explicit calls to request(int) to receive messages.

Note that for cases where the runtime knows that only one inbound message is allowed calling this method will have no effect and the runtime will always permit one and only one message. This is true for:

• MethodDescriptor.MethodType.UNARY operations on both the client and server.
• MethodDescriptor.MethodType.CLIENT_STREAMING operations on the server.
• MethodDescriptor.MethodType.SERVER_STREAMING operations on the client.

request

public abstract void request(int count)

Requests the peer to produce count more messages to be delivered to the 'inbound' StreamObserver.

Parameters:

count - more messages

setMessageCompression

public abstract void setMessageCompression(boolean enable)

Sets message compression for subsequent calls to StreamObserver.onNext(V).

Parameters:

enable - whether to enable compression.