62 * r.run(); 63 * } 64 * }</pre> 65 * 66 * More typically, tasks are executed in some thread other 67 * than the caller's thread. The executor below spawns a new thread 68 * for each task. 69 * 70 * <pre> 71 * class ThreadPerTaskExecutor implements Executor { 72 * public void execute(Runnable r) { 73 * new Thread(r).start(); 74 * } 75 * }</pre> 76 * 77 * Many <tt>Executor</tt> implementations impose some sort of 78 * limitation on how and when tasks are scheduled. The executor below 79 * serializes the submission of tasks to a second executor, 80 * illustrating a composite executor. 81 * 82 * <pre> 83 * class SerialExecutor implements Executor { 84 * final Queue<Runnable> tasks = new ArrayDeque<Runnable>(); 85 * final Executor executor; 86 * Runnable active; 87 * 88 * SerialExecutor(Executor executor) { 89 * this.executor = executor; 90 * } 91 * 92 * public synchronized void execute(final Runnable r) { 93 * tasks.offer(new Runnable() { 94 * public void run() { 95 * try { 96 * r.run(); 97 * } finally { 98 * scheduleNext(); 99 * } 100 * } 101 * }); 102 * if (active == null) { 103 * scheduleNext(); 104 * } 105 * } 106 * 107 * protected synchronized void scheduleNext() { 108 * if ((active = tasks.poll()) != null) { 109 * executor.execute(active); 110 * } 111 * } 112 * }</pre> 113 * 114 * The <tt>Executor</tt> implementations provided in this package 115 * implement {@link ExecutorService}, which is a more extensive 116 * interface. The {@link ThreadPoolExecutor} class provides an 117 * extensible thread pool implementation. The {@link Executors} class 118 * provides convenient factory methods for these Executors. 119 * 120 * <p>Memory consistency effects: Actions in a thread prior to 121 * submitting a {@code Runnable} object to an {@code Executor} 122 * <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a> 123 * its execution begins, perhaps in another thread. 124 * 125 * @since 1.5 126 * @author Doug Lea 127 */ 128 public interface Executor { 129 130 /** 131 * Executes the given command at some time in the future. The command 132 * may execute in a new thread, in a pooled thread, or in the calling | 62 * r.run(); 63 * } 64 * }</pre> 65 * 66 * More typically, tasks are executed in some thread other 67 * than the caller's thread. The executor below spawns a new thread 68 * for each task. 69 * 70 * <pre> 71 * class ThreadPerTaskExecutor implements Executor { 72 * public void execute(Runnable r) { 73 * new Thread(r).start(); 74 * } 75 * }</pre> 76 * 77 * Many <tt>Executor</tt> implementations impose some sort of 78 * limitation on how and when tasks are scheduled. The executor below 79 * serializes the submission of tasks to a second executor, 80 * illustrating a composite executor. 81 * 82 * <pre> {@code 83 * class SerialExecutor implements Executor { 84 * final Queue<Runnable> tasks = new ArrayDeque<Runnable>(); 85 * final Executor executor; 86 * Runnable active; 87 * 88 * SerialExecutor(Executor executor) { 89 * this.executor = executor; 90 * } 91 * 92 * public synchronized void execute(final Runnable r) { 93 * tasks.offer(new Runnable() { 94 * public void run() { 95 * try { 96 * r.run(); 97 * } finally { 98 * scheduleNext(); 99 * } 100 * } 101 * }); 102 * if (active == null) { 103 * scheduleNext(); 104 * } 105 * } 106 * 107 * protected synchronized void scheduleNext() { 108 * if ((active = tasks.poll()) != null) { 109 * executor.execute(active); 110 * } 111 * } 112 * }}</pre> 113 * 114 * The <tt>Executor</tt> implementations provided in this package 115 * implement {@link ExecutorService}, which is a more extensive 116 * interface. The {@link ThreadPoolExecutor} class provides an 117 * extensible thread pool implementation. The {@link Executors} class 118 * provides convenient factory methods for these Executors. 119 * 120 * <p>Memory consistency effects: Actions in a thread prior to 121 * submitting a {@code Runnable} object to an {@code Executor} 122 * <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a> 123 * its execution begins, perhaps in another thread. 124 * 125 * @since 1.5 126 * @author Doug Lea 127 */ 128 public interface Executor { 129 130 /** 131 * Executes the given command at some time in the future. The command 132 * may execute in a new thread, in a pooled thread, or in the calling |