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Diffstat (limited to 'src/actors/scala/actors/threadpool/Executors.java')
| -rw-r--r-- | src/actors/scala/actors/threadpool/Executors.java | 667 |
1 files changed, 0 insertions, 667 deletions
diff --git a/src/actors/scala/actors/threadpool/Executors.java b/src/actors/scala/actors/threadpool/Executors.java deleted file mode 100644 index 49a127a8db..0000000000 --- a/src/actors/scala/actors/threadpool/Executors.java +++ /dev/null @@ -1,667 +0,0 @@ -/* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/licenses/publicdomain - */ - -package scala.actors.threadpool; -//import edu.emory.mathcs.backport.java.util.*; -import java.security.AccessControlContext; -import java.security.AccessController; -import java.security.PrivilegedAction; -import java.security.PrivilegedExceptionAction; -import java.security.AccessControlException; -import java.util.List; -import java.util.Collection; - -/** - * Factory and utility methods for {@link Executor}, {@link - * ExecutorService}, {@link ScheduledExecutorService}, {@link - * ThreadFactory}, and {@link Callable} classes defined in this - * package. This class supports the following kinds of methods: - * - * <ul> - * <li> Methods that create and return an {@link ExecutorService} - * set up with commonly useful configuration settings. - * <li> Methods that create and return a {@link ScheduledExecutorService} - * set up with commonly useful configuration settings. - * <li> Methods that create and return a "wrapped" ExecutorService, that - * disables reconfiguration by making implementation-specific methods - * inaccessible. - * <li> Methods that create and return a {@link ThreadFactory} - * that sets newly created threads to a known state. - * <li> Methods that create and return a {@link Callable} - * out of other closure-like forms, so they can be used - * in execution methods requiring <tt>Callable</tt>. - * </ul> - * - * @since 1.5 - * @author Doug Lea - */ -public class Executors { - - /** - * Creates a thread pool that reuses a fixed number of threads - * operating off a shared unbounded queue. At any point, at most - * <tt>nThreads</tt> threads will be active processing tasks. - * If additional tasks are submitted when all threads are active, - * they will wait in the queue until a thread is available. - * If any thread terminates due to a failure during execution - * prior to shutdown, a new one will take its place if needed to - * execute subsequent tasks. The threads in the pool will exist - * until it is explicitly {@link ExecutorService#shutdown shutdown}. - * - * @param nThreads the number of threads in the pool - * @return the newly created thread pool - * @throws IllegalArgumentException if <tt>nThreads <= 0</tt> - */ - public static ExecutorService newFixedThreadPool(int nThreads) { - return new ThreadPoolExecutor(nThreads, nThreads, - 0L, TimeUnit.MILLISECONDS, - new LinkedBlockingQueue()); - } - - /** - * Creates a thread pool that reuses a fixed number of threads - * operating off a shared unbounded queue, using the provided - * ThreadFactory to create new threads when needed. At any point, - * at most <tt>nThreads</tt> threads will be active processing - * tasks. If additional tasks are submitted when all threads are - * active, they will wait in the queue until a thread is - * available. If any thread terminates due to a failure during - * execution prior to shutdown, a new one will take its place if - * needed to execute subsequent tasks. The threads in the pool will - * exist until it is explicitly {@link ExecutorService#shutdown - * shutdown}. - * - * @param nThreads the number of threads in the pool - * @param threadFactory the factory to use when creating new threads - * @return the newly created thread pool - * @throws NullPointerException if threadFactory is null - * @throws IllegalArgumentException if <tt>nThreads <= 0</tt> - */ - public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory) { - return new ThreadPoolExecutor(nThreads, nThreads, - 0L, TimeUnit.MILLISECONDS, - new LinkedBlockingQueue(), - threadFactory); - } - - /** - * Creates an Executor that uses a single worker thread operating - * off an unbounded queue. (Note however that if this single - * thread terminates due to a failure during execution prior to - * shutdown, a new one will take its place if needed to execute - * subsequent tasks.) Tasks are guaranteed to execute - * sequentially, and no more than one task will be active at any - * given time. Unlike the otherwise equivalent - * <tt>newFixedThreadPool(1)</tt> the returned executor is - * guaranteed not to be reconfigurable to use additional threads. - * - * @return the newly created single-threaded Executor - */ - public static ExecutorService newSingleThreadExecutor() { - return new FinalizableDelegatedExecutorService - (new ThreadPoolExecutor(1, 1, - 0L, TimeUnit.MILLISECONDS, - new LinkedBlockingQueue())); - } - - /** - * Creates an Executor that uses a single worker thread operating - * off an unbounded queue, and uses the provided ThreadFactory to - * create a new thread when needed. Unlike the otherwise - * equivalent <tt>newFixedThreadPool(1, threadFactory)</tt> the - * returned executor is guaranteed not to be reconfigurable to use - * additional threads. - * - * @param threadFactory the factory to use when creating new - * threads - * - * @return the newly created single-threaded Executor - * @throws NullPointerException if threadFactory is null - */ - public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory) { - return new FinalizableDelegatedExecutorService - (new ThreadPoolExecutor(1, 1, - 0L, TimeUnit.MILLISECONDS, - new LinkedBlockingQueue(), - threadFactory)); - } - - /** - * Creates a thread pool that creates new threads as needed, but - * will reuse previously constructed threads when they are - * available. These pools will typically improve the performance - * of programs that execute many short-lived asynchronous tasks. - * Calls to <tt>execute</tt> will reuse previously constructed - * threads if available. If no existing thread is available, a new - * thread will be created and added to the pool. Threads that have - * not been used for sixty seconds are terminated and removed from - * the cache. Thus, a pool that remains idle for long enough will - * not consume any resources. Note that pools with similar - * properties but different details (for example, timeout parameters) - * may be created using {@link ThreadPoolExecutor} constructors. - * - * @return the newly created thread pool - */ - public static ExecutorService newCachedThreadPool() { - return new ThreadPoolExecutor(0, Integer.MAX_VALUE, - 60L, TimeUnit.SECONDS, - new SynchronousQueue()); - } - - /** - * Creates a thread pool that creates new threads as needed, but - * will reuse previously constructed threads when they are - * available, and uses the provided - * ThreadFactory to create new threads when needed. - * @param threadFactory the factory to use when creating new threads - * @return the newly created thread pool - * @throws NullPointerException if threadFactory is null - */ - public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) { - return new ThreadPoolExecutor(0, Integer.MAX_VALUE, - 60L, TimeUnit.SECONDS, - new SynchronousQueue(), - threadFactory); - } - - /** - * Creates a single-threaded executor that can schedule commands - * to run after a given delay, or to execute periodically. - * (Note however that if this single - * thread terminates due to a failure during execution prior to - * shutdown, a new one will take its place if needed to execute - * subsequent tasks.) Tasks are guaranteed to execute - * sequentially, and no more than one task will be active at any - * given time. Unlike the otherwise equivalent - * <tt>newScheduledThreadPool(1)</tt> the returned executor is - * guaranteed not to be reconfigurable to use additional threads. - * @return the newly created scheduled executor - */ - /* public static ScheduledExecutorService newSingleThreadScheduledExecutor() { - return new DelegatedScheduledExecutorService - (new ScheduledThreadPoolExecutor(1)); - } - */ - /** - * Creates a single-threaded executor that can schedule commands - * to run after a given delay, or to execute periodically. (Note - * however that if this single thread terminates due to a failure - * during execution prior to shutdown, a new one will take its - * place if needed to execute subsequent tasks.) Tasks are - * guaranteed to execute sequentially, and no more than one task - * will be active at any given time. Unlike the otherwise - * equivalent <tt>newScheduledThreadPool(1, threadFactory)</tt> - * the returned executor is guaranteed not to be reconfigurable to - * use additional threads. - * @param threadFactory the factory to use when creating new - * threads - * @return a newly created scheduled executor - * @throws NullPointerException if threadFactory is null - */ - /* public static ScheduledExecutorService newSingleThreadScheduledExecutor(ThreadFactory threadFactory) { - return new DelegatedScheduledExecutorService - (new ScheduledThreadPoolExecutor(1, threadFactory)); - } - */ - /** - * Creates a thread pool that can schedule commands to run after a - * given delay, or to execute periodically. - * @param corePoolSize the number of threads to keep in the pool, - * even if they are idle. - * @return a newly created scheduled thread pool - * @throws IllegalArgumentException if <tt>corePoolSize < 0</tt> - */ - /* public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) { - return new ScheduledThreadPoolExecutor(corePoolSize); - } - */ - /** - * Creates a thread pool that can schedule commands to run after a - * given delay, or to execute periodically. - * @param corePoolSize the number of threads to keep in the pool, - * even if they are idle. - * @param threadFactory the factory to use when the executor - * creates a new thread. - * @return a newly created scheduled thread pool - * @throws IllegalArgumentException if <tt>corePoolSize < 0</tt> - * @throws NullPointerException if threadFactory is null - */ - /* public static ScheduledExecutorService newScheduledThreadPool( - int corePoolSize, ThreadFactory threadFactory) { - return new ScheduledThreadPoolExecutor(corePoolSize, threadFactory); - } - */ - - /** - * Returns an object that delegates all defined {@link - * ExecutorService} methods to the given executor, but not any - * other methods that might otherwise be accessible using - * casts. This provides a way to safely "freeze" configuration and - * disallow tuning of a given concrete implementation. - * @param executor the underlying implementation - * @return an <tt>ExecutorService</tt> instance - * @throws NullPointerException if executor null - */ - public static ExecutorService unconfigurableExecutorService(ExecutorService executor) { - if (executor == null) - throw new NullPointerException(); - return new DelegatedExecutorService(executor); - } - - /** - * Returns an object that delegates all defined {@link - * ScheduledExecutorService} methods to the given executor, but - * not any other methods that might otherwise be accessible using - * casts. This provides a way to safely "freeze" configuration and - * disallow tuning of a given concrete implementation. - * @param executor the underlying implementation - * @return a <tt>ScheduledExecutorService</tt> instance - * @throws NullPointerException if executor null - */ - /* public static ScheduledExecutorService unconfigurableScheduledExecutorService(ScheduledExecutorService executor) { - if (executor == null) - throw new NullPointerException(); - return new DelegatedScheduledExecutorService(executor); - } - */ - /** - * Returns a default thread factory used to create new threads. - * This factory creates all new threads used by an Executor in the - * same {@link ThreadGroup}. If there is a {@link - * java.lang.SecurityManager}, it uses the group of {@link - * System#getSecurityManager}, else the group of the thread - * invoking this <tt>defaultThreadFactory</tt> method. Each new - * thread is created as a non-daemon thread with priority set to - * the smaller of <tt>Thread.NORM_PRIORITY</tt> and the maximum - * priority permitted in the thread group. New threads have names - * accessible via {@link Thread#getName} of - * <em>pool-N-thread-M</em>, where <em>N</em> is the sequence - * number of this factory, and <em>M</em> is the sequence number - * of the thread created by this factory. - * @return a thread factory - */ - public static ThreadFactory defaultThreadFactory() { - return new DefaultThreadFactory(); - } - - /** - * Returns a thread factory used to create new threads that - * have the same permissions as the current thread. - * This factory creates threads with the same settings as {@link - * Executors#defaultThreadFactory}, additionally setting the - * AccessControlContext and contextClassLoader of new threads to - * be the same as the thread invoking this - * <tt>privilegedThreadFactory</tt> method. A new - * <tt>privilegedThreadFactory</tt> can be created within an - * {@link AccessController#doPrivileged} action setting the - * current thread's access control context to create threads with - * the selected permission settings holding within that action. - * - * <p> Note that while tasks running within such threads will have - * the same access control and class loader settings as the - * current thread, they need not have the same {@link - * java.lang.ThreadLocal} or {@link - * java.lang.InheritableThreadLocal} values. If necessary, - * particular values of thread locals can be set or reset before - * any task runs in {@link ThreadPoolExecutor} subclasses using - * {@link ThreadPoolExecutor#beforeExecute}. Also, if it is - * necessary to initialize worker threads to have the same - * InheritableThreadLocal settings as some other designated - * thread, you can create a custom ThreadFactory in which that - * thread waits for and services requests to create others that - * will inherit its values. - * - * @return a thread factory - * @throws AccessControlException if the current access control - * context does not have permission to both get and set context - * class loader. - */ - public static ThreadFactory privilegedThreadFactory() { - return new PrivilegedThreadFactory(); - } - - /** - * Returns a {@link Callable} object that, when - * called, runs the given task and returns the given result. This - * can be useful when applying methods requiring a - * <tt>Callable</tt> to an otherwise resultless action. - * @param task the task to run - * @param result the result to return - * @return a callable object - * @throws NullPointerException if task null - */ - public static Callable callable(Runnable task, Object result) { - if (task == null) - throw new NullPointerException(); - return new RunnableAdapter(task, result); - } - - /** - * Returns a {@link Callable} object that, when - * called, runs the given task and returns <tt>null</tt>. - * @param task the task to run - * @return a callable object - * @throws NullPointerException if task null - */ - public static Callable callable(Runnable task) { - if (task == null) - throw new NullPointerException(); - return new RunnableAdapter(task, null); - } - - /** - * Returns a {@link Callable} object that, when - * called, runs the given privileged action and returns its result. - * @param action the privileged action to run - * @return a callable object - * @throws NullPointerException if action null - */ - public static Callable callable(final PrivilegedAction action) { - if (action == null) - throw new NullPointerException(); - return new Callable() { - public Object call() { return action.run(); }}; - } - - /** - * Returns a {@link Callable} object that, when - * called, runs the given privileged exception action and returns - * its result. - * @param action the privileged exception action to run - * @return a callable object - * @throws NullPointerException if action null - */ - public static Callable callable(final PrivilegedExceptionAction action) { - if (action == null) - throw new NullPointerException(); - return new Callable() { - public Object call() throws Exception { return action.run(); }}; - } - - /** - * Returns a {@link Callable} object that will, when - * called, execute the given <tt>callable</tt> under the current - * access control context. This method should normally be - * invoked within an {@link AccessController#doPrivileged} action - * to create callables that will, if possible, execute under the - * selected permission settings holding within that action; or if - * not possible, throw an associated {@link - * AccessControlException}. - * @param callable the underlying task - * @return a callable object - * @throws NullPointerException if callable null - * - */ - public static Callable privilegedCallable(Callable callable) { - if (callable == null) - throw new NullPointerException(); - return new PrivilegedCallable(callable); - } - - /** - * Returns a {@link Callable} object that will, when - * called, execute the given <tt>callable</tt> under the current - * access control context, with the current context class loader - * as the context class loader. This method should normally be - * invoked within an {@link AccessController#doPrivileged} action - * to create callables that will, if possible, execute under the - * selected permission settings holding within that action; or if - * not possible, throw an associated {@link - * AccessControlException}. - * @param callable the underlying task - * - * @return a callable object - * @throws NullPointerException if callable null - * @throws AccessControlException if the current access control - * context does not have permission to both set and get context - * class loader. - */ - public static Callable privilegedCallableUsingCurrentClassLoader(Callable callable) { - if (callable == null) - throw new NullPointerException(); - return new PrivilegedCallableUsingCurrentClassLoader(callable); - } - - // Non-public classes supporting the public methods - - /** - * A callable that runs given task and returns given result - */ - static final class RunnableAdapter implements Callable { - final Runnable task; - final Object result; - RunnableAdapter(Runnable task, Object result) { - this.task = task; - this.result = result; - } - public Object call() { - task.run(); - return result; - } - } - - /** - * A callable that runs under established access control settings - */ - static final class PrivilegedCallable implements Callable { - private final AccessControlContext acc; - private final Callable task; - private Object result; - private Exception exception; - PrivilegedCallable(Callable task) { - this.task = task; - this.acc = AccessController.getContext(); - } - - public Object call() throws Exception { - AccessController.doPrivileged(new PrivilegedAction() { - public Object run() { - try { - result = task.call(); - } catch (Exception ex) { - exception = ex; - } - return null; - } - }, acc); - if (exception != null) - throw exception; - else - return result; - } - } - - /** - * A callable that runs under established access control settings and - * current ClassLoader - */ - static final class PrivilegedCallableUsingCurrentClassLoader implements Callable { - private final ClassLoader ccl; - private final AccessControlContext acc; - private final Callable task; - private Object result; - private Exception exception; - PrivilegedCallableUsingCurrentClassLoader(Callable task) { - this.task = task; - this.ccl = Thread.currentThread().getContextClassLoader(); - this.acc = AccessController.getContext(); - acc.checkPermission(new RuntimePermission("getContextClassLoader")); - acc.checkPermission(new RuntimePermission("setContextClassLoader")); - } - - public Object call() throws Exception { - AccessController.doPrivileged(new PrivilegedAction() { - public Object run() { - ClassLoader savedcl = null; - Thread t = Thread.currentThread(); - try { - ClassLoader cl = t.getContextClassLoader(); - if (ccl != cl) { - t.setContextClassLoader(ccl); - savedcl = cl; - } - result = task.call(); - } catch (Exception ex) { - exception = ex; - } finally { - if (savedcl != null) - t.setContextClassLoader(savedcl); - } - return null; - } - }, acc); - if (exception != null) - throw exception; - else - return result; - } - } - - /** - * The default thread factory - */ - static class DefaultThreadFactory implements ThreadFactory { - static final AtomicInteger poolNumber = new AtomicInteger(1); - final ThreadGroup group; - final AtomicInteger threadNumber = new AtomicInteger(1); - final String namePrefix; - - DefaultThreadFactory() { - SecurityManager s = System.getSecurityManager(); - group = (s != null)? s.getThreadGroup() : - Thread.currentThread().getThreadGroup(); - namePrefix = "pool-" + - poolNumber.getAndIncrement() + - "-thread-"; - } - - public Thread newThread(Runnable r) { - Thread t = new Thread(group, r, - namePrefix + threadNumber.getAndIncrement(), - 0); - if (t.isDaemon()) - t.setDaemon(false); - if (t.getPriority() != Thread.NORM_PRIORITY) - t.setPriority(Thread.NORM_PRIORITY); - return t; - } - } - - /** - * Thread factory capturing access control and class loader - */ - static class PrivilegedThreadFactory extends DefaultThreadFactory { - private final ClassLoader ccl; - private final AccessControlContext acc; - - PrivilegedThreadFactory() { - super(); - this.ccl = Thread.currentThread().getContextClassLoader(); - this.acc = AccessController.getContext(); - acc.checkPermission(new RuntimePermission("setContextClassLoader")); - } - - public Thread newThread(final Runnable r) { - return super.newThread(new Runnable() { - public void run() { - AccessController.doPrivileged(new PrivilegedAction() { - public Object run() { - Thread.currentThread().setContextClassLoader(ccl); - r.run(); - return null; - } - }, acc); - } - }); - } - - } - - /** - * A wrapper class that exposes only the ExecutorService methods - * of an ExecutorService implementation. - */ - static class DelegatedExecutorService extends AbstractExecutorService { - private final ExecutorService e; - DelegatedExecutorService(ExecutorService executor) { e = executor; } - public void execute(Runnable command) { e.execute(command); } - public void shutdown() { e.shutdown(); } - public List shutdownNow() { return e.shutdownNow(); } - public boolean isShutdown() { return e.isShutdown(); } - public boolean isTerminated() { return e.isTerminated(); } - public boolean awaitTermination(long timeout, TimeUnit unit) - throws InterruptedException { - return e.awaitTermination(timeout, unit); - } - public Future submit(Runnable task) { - return e.submit(task); - } - public Future submit(Callable task) { - return e.submit(task); - } - public Future submit(Runnable task, Object result) { - return e.submit(task, result); - } - public List<Future> invokeAll(Collection tasks) - throws InterruptedException { - return e.invokeAll(tasks); - } - public List<Future> invokeAll(Collection tasks, - long timeout, TimeUnit unit) - throws InterruptedException { - return e.invokeAll(tasks, timeout, unit); - } - public Object invokeAny(Collection tasks) - throws InterruptedException, ExecutionException { - return e.invokeAny(tasks); - } - public Object invokeAny(Collection tasks, - long timeout, TimeUnit unit) - throws InterruptedException, ExecutionException, TimeoutException { - return e.invokeAny(tasks, timeout, unit); - } - } - - static class FinalizableDelegatedExecutorService - extends DelegatedExecutorService { - FinalizableDelegatedExecutorService(ExecutorService executor) { - super(executor); - } - protected void finalize() { - super.shutdown(); - } - } - - /** - * A wrapper class that exposes only the ScheduledExecutorService - * methods of a ScheduledExecutorService implementation. - */ - /* static class DelegatedScheduledExecutorService - extends DelegatedExecutorService - implements ScheduledExecutorService { - private final ScheduledExecutorService e; - DelegatedScheduledExecutorService(ScheduledExecutorService executor) { - super(executor); - e = executor; - } - public ScheduledFuture schedule(Runnable command, long delay, TimeUnit unit) { - return e.schedule(command, delay, unit); - } - public ScheduledFuture schedule(Callable callable, long delay, TimeUnit unit) { - return e.schedule(callable, delay, unit); - } - public ScheduledFuture scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) { - return e.scheduleAtFixedRate(command, initialDelay, period, unit); - } - public ScheduledFuture scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) { - return e.scheduleWithFixedDelay(command, initialDelay, delay, unit); - } - } -*/ - - /** Cannot instantiate. */ - private Executors() {} -} |