Thomas Vachuska | b0317c6 | 2015-04-08 23:58:58 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2015 Open Networking Laboratory |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.onlab.util; |
| 17 | |
| 18 | import java.util.Collection; |
| 19 | import java.util.List; |
| 20 | import java.util.concurrent.Callable; |
| 21 | import java.util.concurrent.ExecutionException; |
| 22 | import java.util.concurrent.ExecutorService; |
| 23 | import java.util.concurrent.Future; |
| 24 | import java.util.concurrent.TimeUnit; |
| 25 | import java.util.concurrent.TimeoutException; |
| 26 | |
| 27 | /** |
| 28 | * Executor service wrapper for shared executors with safeguards on shutdown |
| 29 | * to prevent inadvertent shutdown. |
| 30 | */ |
| 31 | class SharedExecutorService implements ExecutorService { |
| 32 | |
| 33 | private static final String NOT_ALLOWED = "Shutdown of shared executor is not allowed"; |
| 34 | |
| 35 | private ExecutorService executor; |
| 36 | |
| 37 | /** |
| 38 | * Creates a wrapper for the given executor service. |
| 39 | * |
| 40 | * @param executor executor service to wrap |
| 41 | */ |
| 42 | SharedExecutorService(ExecutorService executor) { |
| 43 | this.executor = executor; |
| 44 | } |
| 45 | |
| 46 | /** |
| 47 | * Returns the backing executor service. |
| 48 | * |
| 49 | * @return backing executor service |
| 50 | */ |
| 51 | ExecutorService backingExecutor() { |
| 52 | return executor; |
| 53 | } |
| 54 | |
| 55 | /** |
| 56 | * Swaps the backing executor with a new one and shuts down the old one. |
| 57 | * |
| 58 | * @param executor new executor service |
| 59 | */ |
| 60 | void setBackingExecutor(ExecutorService executor) { |
| 61 | ExecutorService oldExecutor = this.executor; |
| 62 | this.executor = executor; |
| 63 | oldExecutor.shutdown(); |
| 64 | } |
| 65 | |
| 66 | @Override |
| 67 | public void shutdown() { |
| 68 | throw new UnsupportedOperationException(NOT_ALLOWED); |
| 69 | } |
| 70 | |
| 71 | @Override |
| 72 | public List<Runnable> shutdownNow() { |
| 73 | throw new UnsupportedOperationException(NOT_ALLOWED); |
| 74 | } |
| 75 | |
| 76 | @Override |
| 77 | public boolean isShutdown() { |
| 78 | return executor.isShutdown(); |
| 79 | } |
| 80 | |
| 81 | @Override |
| 82 | public boolean isTerminated() { |
| 83 | return executor.isTerminated(); |
| 84 | } |
| 85 | |
| 86 | @Override |
| 87 | public boolean awaitTermination(long timeout, TimeUnit unit) |
| 88 | throws InterruptedException { |
| 89 | return executor.awaitTermination(timeout, unit); |
| 90 | } |
| 91 | |
| 92 | @Override |
| 93 | public <T> Future<T> submit(Callable<T> task) { |
| 94 | return executor.submit(task); |
| 95 | } |
| 96 | |
| 97 | @Override |
| 98 | public <T> Future<T> submit(Runnable task, T result) { |
| 99 | return executor.submit(task, result); |
| 100 | } |
| 101 | |
| 102 | @Override |
| 103 | public Future<?> submit(Runnable task) { |
| 104 | return executor.submit(task); |
| 105 | } |
| 106 | |
| 107 | @Override |
| 108 | public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) |
| 109 | throws InterruptedException { |
| 110 | return executor.invokeAll(tasks); |
| 111 | } |
| 112 | |
| 113 | @Override |
| 114 | public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, |
| 115 | long timeout, TimeUnit unit) |
| 116 | throws InterruptedException { |
| 117 | return executor.invokeAll(tasks, timeout, unit); |
| 118 | } |
| 119 | |
| 120 | @Override |
| 121 | public <T> T invokeAny(Collection<? extends Callable<T>> tasks) |
| 122 | throws InterruptedException, ExecutionException { |
| 123 | return executor.invokeAny(tasks); |
| 124 | } |
| 125 | |
| 126 | @Override |
| 127 | public <T> T invokeAny(Collection<? extends Callable<T>> tasks, |
| 128 | long timeout, TimeUnit unit) |
| 129 | throws InterruptedException, ExecutionException, TimeoutException { |
HIGUCHI Yuta | 1651e98 | 2015-09-04 13:45:08 -0700 | [diff] [blame] | 130 | return executor.invokeAny(tasks, timeout, unit); |
Thomas Vachuska | b0317c6 | 2015-04-08 23:58:58 -0700 | [diff] [blame] | 131 | } |
| 132 | |
| 133 | @Override |
| 134 | public void execute(Runnable command) { |
| 135 | executor.execute(command); |
| 136 | } |
| 137 | |
| 138 | } |