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;
  
  /**
   * The optimizer may split run the user combiner in 3 separate phases (ADD, MERGE, and EXTRACT), on
   * separate VMs, as it sees fit. The CombinerPhase dictates which DoFn is actually running in the
   * worker.
   */
  // TODO: These strings are part of the service definition, and
  // should be added into the definition of the ParDoInstruction,
  // but the protiary definitions don't allow for enums yet.
  public class CombinePhase {
    public static final String ALL = "all";
    public static final String ADD = "add";
    public static final String MERGE = "merge";
    public static final String EXTRACT = "extract";
  }
  