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package sun.nio.ch;

import java.nio.channels.*;
import java.util.concurrent.*;
import java.security.AccessController;
import sun.security.action.GetIntegerAction;

Defines static methods to invoke a completion handler or arbitrary task.
/** * Defines static methods to invoke a completion handler or arbitrary task. */
class Invoker { private Invoker() { } // maximum number of completion handlers that may be invoked on the current // thread before it re-directs invocations to the thread pool. This helps // avoid stack overflow and lessens the risk of starvation. private static final int maxHandlerInvokeCount = AccessController.doPrivileged( new GetIntegerAction("sun.nio.ch.maxCompletionHandlersOnStack", 16)); // Per-thread object with reference to channel group and a counter for // the number of completion handlers invoked. This should be reset to 0 // when all completion handlers have completed. static class GroupAndInvokeCount { private final AsynchronousChannelGroupImpl group; private int handlerInvokeCount; GroupAndInvokeCount(AsynchronousChannelGroupImpl group) { this.group = group; } AsynchronousChannelGroupImpl group() { return group; } int invokeCount() { return handlerInvokeCount; } void setInvokeCount(int value) { handlerInvokeCount = value; } void resetInvokeCount() { handlerInvokeCount = 0; } void incrementInvokeCount() { handlerInvokeCount++; } } private static final ThreadLocal<GroupAndInvokeCount> myGroupAndInvokeCount = new ThreadLocal<GroupAndInvokeCount>() { @Override protected GroupAndInvokeCount initialValue() { return null; } };
Binds this thread to the given group
/** * Binds this thread to the given group */
static void bindToGroup(AsynchronousChannelGroupImpl group) { myGroupAndInvokeCount.set(new GroupAndInvokeCount(group)); }
Returns the GroupAndInvokeCount object for this thread.
/** * Returns the GroupAndInvokeCount object for this thread. */
static GroupAndInvokeCount getGroupAndInvokeCount() { return myGroupAndInvokeCount.get(); }
Returns true if the current thread is in a channel group's thread pool
/** * Returns true if the current thread is in a channel group's thread pool */
static boolean isBoundToAnyGroup() { return myGroupAndInvokeCount.get() != null; }
Returns true if the current thread is in the given channel's thread pool and we haven't exceeded the maximum number of handler frames on the stack.
/** * Returns true if the current thread is in the given channel's thread * pool and we haven't exceeded the maximum number of handler frames on * the stack. */
static boolean mayInvokeDirect(GroupAndInvokeCount myGroupAndInvokeCount, AsynchronousChannelGroupImpl group) { if ((myGroupAndInvokeCount != null) && (myGroupAndInvokeCount.group() == group) && (myGroupAndInvokeCount.invokeCount() < maxHandlerInvokeCount)) { return true; } return false; }
Invoke handler without checking the thread identity or number of handlers on the thread stack.
/** * Invoke handler without checking the thread identity or number of handlers * on the thread stack. */
static <V,A> void invokeUnchecked(CompletionHandler<V,? super A> handler, A attachment, V value, Throwable exc) { if (exc == null) { handler.completed(value, attachment); } else { handler.failed(exc, attachment); } // clear interrupt Thread.interrupted(); // clear thread locals when in default thread pool if (System.getSecurityManager() != null) { Thread me = Thread.currentThread(); if (me instanceof sun.misc.InnocuousThread) { GroupAndInvokeCount thisGroupAndInvokeCount = myGroupAndInvokeCount.get(); ((sun.misc.InnocuousThread)me).eraseThreadLocals(); if (thisGroupAndInvokeCount != null) { myGroupAndInvokeCount.set(thisGroupAndInvokeCount); } } } }
Invoke handler assuming thread identity already checked
/** * Invoke handler assuming thread identity already checked */
static <V,A> void invokeDirect(GroupAndInvokeCount myGroupAndInvokeCount, CompletionHandler<V,? super A> handler, A attachment, V result, Throwable exc) { myGroupAndInvokeCount.incrementInvokeCount(); Invoker.invokeUnchecked(handler, attachment, result, exc); }
Invokes the handler. If the current thread is in the channel group's thread pool then the handler is invoked directly, otherwise it is invoked indirectly.
/** * Invokes the handler. If the current thread is in the channel group's * thread pool then the handler is invoked directly, otherwise it is * invoked indirectly. */
static <V,A> void invoke(AsynchronousChannel channel, CompletionHandler<V,? super A> handler, A attachment, V result, Throwable exc) { boolean invokeDirect = false; boolean identityOkay = false; GroupAndInvokeCount thisGroupAndInvokeCount = myGroupAndInvokeCount.get(); if (thisGroupAndInvokeCount != null) { if ((thisGroupAndInvokeCount.group() == ((Groupable)channel).group())) identityOkay = true; if (identityOkay && (thisGroupAndInvokeCount.invokeCount() < maxHandlerInvokeCount)) { // group match invokeDirect = true; } } if (invokeDirect) { invokeDirect(thisGroupAndInvokeCount, handler, attachment, result, exc); } else { try { invokeIndirectly(channel, handler, attachment, result, exc); } catch (RejectedExecutionException ree) { // channel group shutdown; fallback to invoking directly // if the current thread has the right identity. if (identityOkay) { invokeDirect(thisGroupAndInvokeCount, handler, attachment, result, exc); } else { throw new ShutdownChannelGroupException(); } } } }
Invokes the handler indirectly via the channel group's thread pool.
/** * Invokes the handler indirectly via the channel group's thread pool. */
static <V,A> void invokeIndirectly(AsynchronousChannel channel, final CompletionHandler<V,? super A> handler, final A attachment, final V result, final Throwable exc) { try { ((Groupable)channel).group().executeOnPooledThread(new Runnable() { public void run() { GroupAndInvokeCount thisGroupAndInvokeCount = myGroupAndInvokeCount.get(); if (thisGroupAndInvokeCount != null) thisGroupAndInvokeCount.setInvokeCount(1); invokeUnchecked(handler, attachment, result, exc); } }); } catch (RejectedExecutionException ree) { throw new ShutdownChannelGroupException(); } }
Invokes the handler "indirectly" in the given Executor
/** * Invokes the handler "indirectly" in the given Executor */
static <V,A> void invokeIndirectly(final CompletionHandler<V,? super A> handler, final A attachment, final V value, final Throwable exc, Executor executor) { try { executor.execute(new Runnable() { public void run() { invokeUnchecked(handler, attachment, value, exc); } }); } catch (RejectedExecutionException ree) { throw new ShutdownChannelGroupException(); } }
Invokes the given task on the thread pool associated with the given channel. If the current thread is in the thread pool then the task is invoked directly.
/** * Invokes the given task on the thread pool associated with the given * channel. If the current thread is in the thread pool then the task is * invoked directly. */
static void invokeOnThreadInThreadPool(Groupable channel, Runnable task) { boolean invokeDirect; GroupAndInvokeCount thisGroupAndInvokeCount = myGroupAndInvokeCount.get(); AsynchronousChannelGroupImpl targetGroup = channel.group(); if (thisGroupAndInvokeCount == null) { invokeDirect = false; } else { invokeDirect = (thisGroupAndInvokeCount.group == targetGroup); } try { if (invokeDirect) { task.run(); } else { targetGroup.executeOnPooledThread(task); } } catch (RejectedExecutionException ree) { throw new ShutdownChannelGroupException(); } }
Invoke handler with completed result. This method does not check the thread identity or the number of handlers on the thread stack.
/** * Invoke handler with completed result. This method does not check the * thread identity or the number of handlers on the thread stack. */
static <V,A> void invokeUnchecked(PendingFuture<V,A> future) { assert future.isDone(); CompletionHandler<V,? super A> handler = future.handler(); if (handler != null) { invokeUnchecked(handler, future.attachment(), future.value(), future.exception()); } }
Invoke handler with completed result. If the current thread is in the channel group's thread pool then the handler is invoked directly, otherwise it is invoked indirectly.
/** * Invoke handler with completed result. If the current thread is in the * channel group's thread pool then the handler is invoked directly, * otherwise it is invoked indirectly. */
static <V,A> void invoke(PendingFuture<V,A> future) { assert future.isDone(); CompletionHandler<V,? super A> handler = future.handler(); if (handler != null) { invoke(future.channel(), handler, future.attachment(), future.value(), future.exception()); } }
Invoke handler with completed result. The handler is invoked indirectly, via the channel group's thread pool.
/** * Invoke handler with completed result. The handler is invoked indirectly, * via the channel group's thread pool. */
static <V,A> void invokeIndirectly(PendingFuture<V,A> future) { assert future.isDone(); CompletionHandler<V,? super A> handler = future.handler(); if (handler != null) { invokeIndirectly(future.channel(), handler, future.attachment(), future.value(), future.exception()); } } }