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.dataflow.worker.util.common.worker;
  
  /** The abstract base class for Operations that have inputs and implement process(). */
  public abstract class ReceivingOperation extends Operation implements Receiver {
  
    public ReceivingOperation(OutputReceiver[] receivers, OperationContext context) {
      super(receivers, context);
    }
  
    /**
     * Adds an input to this Operation, coming from the given output of the given source Operation.
     */
    public void attachInput(Operation source, int outputNum) {
      checkUnstarted();
      OutputReceiver fanOut = source.receivers[outputNum];
      fanOut.addOutput(this);
    }
  }
  