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.beam.runners.fnexecution.environment;
  
  import net.jcip.annotations.ThreadSafe;
  import org.apache.beam.model.pipeline.v1.RunnerApi.Environment;
  import org.apache.beam.runners.fnexecution.control.InstructionRequestHandler;
  
  /** A {@link RemoteEnvironment} that connects to Dataflow runner harness. */
  @ThreadSafe
  public class StaticRemoteEnvironment implements RemoteEnvironment {
  
    static StaticRemoteEnvironment create(
        Environment environment, InstructionRequestHandler instructionRequestHandler) {
      return new StaticRemoteEnvironment(environment, instructionRequestHandler);
    }
  
    private final Environment environment;
    private final InstructionRequestHandler instructionRequestHandler;
  
    private boolean isClosed = false;
  
    private StaticRemoteEnvironment(
        Environment environment, InstructionRequestHandler instructionRequestHandler) {
      this.environment = environment;
      this.instructionRequestHandler = instructionRequestHandler;
    }
  
    @Override
    public Environment getEnvironment() {
      return this.environment;
    }
  
    @Override
    public InstructionRequestHandler getInstructionRequestHandler() {
      return this.instructionRequestHandler;
    }
  
    @Override
    public synchronized void close() throws Exception {
      // The instruction handler should each only be terminated once.
      // Do nothing if we have already requested termination.
      if (!isClosed) {
        return;
      }
      isClosed = true;
      this.instructionRequestHandler.close();
    }
  }
  