content: /*
   * 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.bifromq.baserpc.server;
  
  import org.apache.bifromq.baserpc.metrics.RPCMetric;
  import io.grpc.stub.StreamObserver;
  import io.reactivex.rxjava3.core.Observable;
  import io.reactivex.rxjava3.subjects.PublishSubject;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  public abstract class AckStream<AckT, MsgT> extends AbstractStreamObserver<AckT, MsgT> {
      private final PublishSubject<AckT> ackSubject = PublishSubject.create();
      private final AtomicBoolean closed = new AtomicBoolean();
  
      protected AckStream(StreamObserver<MsgT> responseObserver) {
          super(responseObserver);
      }
  
      public Observable<AckT> ack() {
          return ackSubject;
      }
  
      public void send(MsgT message) {
          responseObserver.onNext(message);
          meter.recordCount(RPCMetric.StreamMsgSendCount);
      }
  
      public void close() {
          if (closed.compareAndSet(false, true)) {
              ackSubject.onComplete();
              if (!responseObserver.isCancelled()) {
                  responseObserver.onCompleted();
              }
          }
      }
  
      @Override
      public final void onNext(AckT value) {
          meter.recordCount(RPCMetric.StreamAckReceiveCount);
          ackSubject.onNext(value);
      }
  
      @Override
      public final void onError(Throwable t) {
          close();
      }
  
      @Override
      public final void onCompleted() {
          close();
      }
  }
  