001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.xbean.kernel; 018 019 import java.util.Set; 020 021 /** 022 * This class contains the built-in common start startegies. 023 * 024 * @author Dain Sundstrom 025 * @version $Id$ 026 * @since 2.0 027 */ 028 public final class StartStrategies { 029 private StartStrategies() { 030 } 031 032 /** 033 * This strategy attempts to immedately start the service. When there are unsatisfied conditions, this strategy 034 * will leave the service in the STARTING state, and throw an UnsatisfiedConditionsException 035 * to the caller. When there is a start error, the service will be destroyed and the exception will be rethrown to 036 * the caller. 037 */ 038 public static final StartStrategy SYNCHRONOUS = new Synchronous(); 039 040 private static class Synchronous implements StartStrategy { 041 public boolean waitForUnsatisfiedConditions(ServiceName serviceName, Set conditions) throws UnsatisfiedConditionsException { 042 throw new UnsatisfiedConditionsException("Unsatisfied start conditions", serviceName, conditions); 043 } 044 045 public void startError(ServiceName serviceName, Throwable startError) throws Exception { 046 if (startError instanceof Exception) { 047 throw (Exception) startError; 048 } else if (startError instanceof Error) { 049 throw (Error) startError; 050 } else { 051 throw new AssertionError(startError); 052 } 053 } 054 } 055 056 /** 057 * This strategy attempts to start the service asynchronously. When there are unsatisfied conditions, this strategy 058 * will leave the service in the STARTING state, and caller will not recieve any exceptions. 059 * When there is a start error the service will be destroyed adn the exception will be sent to the service montior. 060 * The caller will not recieve any start exception. 061 */ 062 public static final StartStrategy ASYNCHRONOUS = new Asynchronous(); 063 064 private static class Asynchronous implements StartStrategy { 065 public boolean waitForUnsatisfiedConditions(ServiceName serviceName, Set conditions) { 066 return false; 067 } 068 069 public void startError(ServiceName serviceName, Throwable startError) { 070 } 071 } 072 073 /** 074 * This strategy wait until the service start. This strategy blocks until all unsatisfied conditons 075 * are satisfied. When there is a start error, the service will be destroyed and the exception will be rethrown to 076 * the caller. 077 */ 078 public static final StartStrategy BLOCK = new Block(); 079 080 private static class Block implements StartStrategy { 081 public boolean waitForUnsatisfiedConditions(ServiceName serviceName, Set conditions) { 082 return true; 083 } 084 085 public void startError(ServiceName serviceName, Throwable startError) throws Exception { 086 if (startError instanceof Exception) { 087 throw (Exception) startError; 088 } else if (startError instanceof Error) { 089 throw (Error) startError; 090 } else { 091 throw new AssertionError(startError); 092 } 093 } 094 } 095 096 /** 097 * This strategy attempts to start the service immedately. When there are unsatisfied conditions or a start error 098 * the dervice will be destroyed and unregistered. In this case an UnsatisfiedConditionsException or 099 * the start error will be thrown to the caller. 100 */ 101 public static final StartStrategy UNREGISTER = new Unregister(); 102 103 private static class Unregister implements StartStrategy { 104 public boolean waitForUnsatisfiedConditions(ServiceName serviceName, Set conditions) throws UnregisterServiceException { 105 UnsatisfiedConditionsException userException = new UnsatisfiedConditionsException("Unsatisfied start conditions", serviceName, conditions); 106 throw new UnregisterServiceException(serviceName, userException); 107 } 108 109 public void startError(ServiceName serviceName, Throwable startError) throws UnregisterServiceException { 110 throw new UnregisterServiceException(serviceName, startError); 111 } 112 } 113 }