001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.reef.runtime.common.driver; 020 021/** 022 * The status of the Driver. 023 */ 024public enum DriverStatus { 025 026 PRE_INIT, 027 INIT, 028 RUNNING, 029 SHUTTING_DOWN, 030 FAILING; 031 032 /** 033 * Check if the driver is in process of shutting down (either gracefully or due to an error). 034 * @return true if the driver is shutting down (gracefully or otherwise). 035 */ 036 public boolean isClosing() { 037 return this == SHUTTING_DOWN || this == FAILING; 038 } 039 040 /** 041 * Check whether a driver state transition from current state to a given one is legal. 042 * @param toStatus Destination state. 043 * @return true if transition is valid, false otherwise. 044 */ 045 public boolean isLegalTransition(final DriverStatus toStatus) { 046 047 switch (this) { 048 049 case PRE_INIT: 050 switch (toStatus) { 051 case INIT: 052 return true; 053 default: 054 return false; 055 } 056 057 case INIT: 058 switch (toStatus) { 059 case RUNNING: 060 return true; 061 default: 062 return false; 063 } 064 065 case RUNNING: 066 switch (toStatus) { 067 case SHUTTING_DOWN: 068 case FAILING: 069 return true; 070 default: 071 return false; 072 } 073 074 case FAILING: 075 case SHUTTING_DOWN: 076 return false; 077 078 default: 079 throw new IllegalStateException("Unknown input state: " + this); 080 } 081 } 082}