001 /** 002 * Copyright (c) 2010 Yahoo! Inc. All rights reserved. 003 * Licensed under the Apache License, Version 2.0 (the "License"); 004 * you may not use this file except in compliance with the License. 005 * You may obtain a copy of the License at 006 * 007 * http://www.apache.org/licenses/LICENSE-2.0 008 * 009 * Unless required by applicable law or agreed to in writing, software 010 * distributed under the License is distributed on an "AS IS" BASIS, 011 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012 * See the License for the specific language governing permissions and 013 * limitations under the License. See accompanying LICENSE file. 014 */ 015 package org.apache.oozie; 016 017 import org.apache.oozie.util.XLog; 018 019 /** 020 * Fault Injection support class. <p/> Concrete classes should be available only during testing, not in production. <p/> 021 * To activate fault injection the {@link #FAULT_INJECTION} system property must be set to true. <p/> When fault 022 * injection is activated, the concrete class (specified by name) will be call for activation. <p/> Concrete classes 023 * should be activated by presense of a second system property. <p/> This fault injection pattern provides 3 levels of 024 * safeguard: a general 'fault injection' system property, the availabity of of the concrete 'fault injection' class in 025 * the classpath, a specifi 'fault injection' system property. <p/> Refer to the <code>SkipCommitFaultInjection</code> 026 * class in the test classes for an example. 027 */ 028 public abstract class FaultInjection { 029 030 public static final String FAULT_INJECTION = "oozie.fault.injection"; 031 032 private static FaultInjection getFaultInjection(String className) { 033 if (Boolean.parseBoolean(System.getProperty(FAULT_INJECTION, "false"))) { 034 try { 035 Class klass = Thread.currentThread().getContextClassLoader().loadClass(className); 036 return (FaultInjection) klass.newInstance(); 037 } 038 catch (ClassNotFoundException ex) { 039 XLog.getLog(FaultInjection.class).warn("Trying to activate fault injection in production", ex); 040 } 041 catch (IllegalAccessException ex) { 042 throw new RuntimeException(XLog.format("Could not initialize [{0}]", className, ex), ex); 043 } 044 catch (InstantiationException ex) { 045 throw new RuntimeException(XLog.format("Could not initialize [{0}]", className, ex), ex); 046 } 047 } 048 return null; 049 } 050 051 public static boolean activate(String className) { 052 FaultInjection fi = getFaultInjection(className); 053 if (fi != null) { 054 className = className.substring(className.lastIndexOf(".") + 1); 055 if (fi.activate()) { 056 XLog.getLog(FaultInjection.class).warn("FAULT INJECTION, ACTIVATING [{0}]", className); 057 return true; 058 } 059 else { 060 XLog.getLog(FaultInjection.class).warn("FAULT INJECTION, DID NOT ACTIVATE [{0}]", className); 061 } 062 } 063 return false; 064 } 065 066 public static void deactivate(String className) { 067 FaultInjection fi = getFaultInjection(className); 068 if (fi != null) { 069 className = className.substring(className.lastIndexOf(".") + 1); 070 if (fi.isActive()) { 071 XLog.getLog(FaultInjection.class).warn("FAULT INJECTION, DEACTIVATING [{0}]", className); 072 fi.deactivate(); 073 } 074 else { 075 XLog.getLog(FaultInjection.class).warn("FAULT INJECTION, CANNOT DEACTIVATE, NOT ACTIVE [{0}]", 076 className); 077 } 078 } 079 } 080 081 public static boolean isActive(String className) { 082 FaultInjection fi = getFaultInjection(className); 083 if (fi != null) { 084 className = className.substring(className.lastIndexOf(".") + 1); 085 if (fi.isActive()) { 086 XLog.getLog(FaultInjection.class).warn("FAULT INJECTION, ACTIVE [{0}]", className); 087 return true; 088 } 089 else { 090 XLog.getLog(FaultInjection.class).warn("FAULT INJECTION, NOT ACTIVE [{0}]", className); 091 } 092 } 093 return false; 094 } 095 096 public abstract boolean activate(); 097 098 public abstract void deactivate(); 099 100 public abstract boolean isActive(); 101 102 }