lang/java/reef-runtime-local/src/main/java/org/apache/reef/runtime/local/process/RunnableProcessState.java

/*
 * 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.reef.runtime.local.process;

/**
 * The possible states of a process: INIT, RUNNING, ENDED.
 */
enum RunnableProcessState {

  /** After initialization. */
  INIT,

  /** The process is running. */
  RUNNING,

  /** The process ended. */
  ENDED;

  /**
   * Check whether a transition from current state to the given one is legal.
   * @param toState destination state.
   * @return True if the state transition is legal, false otherwise.
   */
  public boolean isLegal(final RunnableProcessState toState) {

    switch (this) {

    case INIT:
      switch (toState) {
      case RUNNING:
      case ENDED:
        return true;
      default:
        return false;
      }

    case RUNNING:
      switch (toState) {
      case ENDED:
        return true;
      default:
        return false;
      }

    case ENDED:
      return false;

    default:
      return false;
    }
  }
}