| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.beam.runners.dataflow.worker.windmill; |
| |
| import java.util.function.Function; |
| import org.apache.beam.sdk.fn.stream.AdvancingPhaser; |
| import org.apache.beam.sdk.options.PipelineOptions; |
| import org.apache.beam.vendor.grpc.v1p13p1.io.grpc.stub.CallStreamObserver; |
| import org.apache.beam.vendor.grpc.v1p13p1.io.grpc.stub.StreamObserver; |
| |
| /** |
| * Uses {@link PipelineOptions} to configure which underlying {@link StreamObserver} implementation |
| * to use. |
| */ |
| public abstract class StreamObserverFactory { |
| public static StreamObserverFactory direct() { |
| return new Direct(); |
| } |
| |
| public abstract <ReqT, RespT> StreamObserver<RespT> from( |
| Function<StreamObserver<ReqT>, StreamObserver<RespT>> clientFactory, |
| StreamObserver<ReqT> responseObserver); |
| |
| private static class Direct extends StreamObserverFactory { |
| Direct() {} |
| |
| @Override |
| public <ReqT, RespT> StreamObserver<RespT> from( |
| Function<StreamObserver<ReqT>, StreamObserver<RespT>> clientFactory, |
| StreamObserver<ReqT> inboundObserver) { |
| AdvancingPhaser phaser = new AdvancingPhaser(1); |
| CallStreamObserver<RespT> outboundObserver = |
| (CallStreamObserver<RespT>) |
| clientFactory.apply( |
| new ForwardingClientResponseObserver<ReqT, RespT>( |
| inboundObserver, phaser::arrive, phaser::forceTermination)); |
| return new DirectStreamObserver<>(phaser, outboundObserver); |
| } |
| } |
| } |