/*

  * 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.giraph.graph;

 /**

  * Each compute node running on the underlying cluster

  * is marked with this enum to indicate the worker or

  * master task(s) it must perform during job runs.

  */

 public enum GraphFunctions {

   /** Undecided yet */

   UNKNOWN {

     @Override public boolean isMaster() { return false; }

     @Override public boolean isWorker() { return false; }

     @Override public boolean isZooKeeper() { return false; }

   },

   /** Only be the master */

   MASTER_ONLY {

     @Override public boolean isMaster() { return true; }

     @Override public boolean isWorker() { return false; }

     @Override public boolean isZooKeeper() { return false; }

   },

   /** Only be the master and ZooKeeper */

   MASTER_ZOOKEEPER_ONLY {

     @Override public boolean isMaster() { return true; }

     @Override public boolean isWorker() { return false; }

     @Override public boolean isZooKeeper() { return true; }

   },

   /** Only be the worker */

   WORKER_ONLY {

     @Override public boolean isMaster() { return false; }

     @Override public boolean isWorker() { return true; }

     @Override public boolean isZooKeeper() { return false; }

   },

   /** Do master, worker, and ZooKeeper */

   ALL {

     @Override public boolean isMaster() { return true; }

     @Override public boolean isWorker() { return true; }

     @Override public boolean isZooKeeper() { return true; }

   },

   /** Do master and worker */

   ALL_EXCEPT_ZOOKEEPER {

     @Override public boolean isMaster() { return true; }

     @Override public boolean isWorker() { return true; }

     @Override public boolean isZooKeeper() { return false; }

   };

   /**

    * Tell whether this function acts as a master.

    *

    * @return true iff this map function is a master

    */

   public abstract boolean isMaster();

   /**

    * Tell whether this function acts as a worker.

    *

    * @return true iff this map function is a worker

    */

   public abstract boolean isWorker();

   /**

    * Tell whether this function acts as a ZooKeeper server.

    *

    * @return true iff this map function is a zookeeper server

    */

   public abstract boolean isZooKeeper();

   public boolean isKnown() {

     return this != UNKNOWN;

   }

   public boolean isUnknown() {

     return !isKnown();

   }

   public boolean isNotAWorker() {

     return isKnown() && !isWorker();

   }

 }