Author: tabish
Date: Sun Sep 7 09:32:01 2008
New Revision: 692895
URL: http://svn.apache.org/viewvc?rev=692895&view=rev
Log:
First cut of the Future interface
Added:
activemq/activemq-cpp/trunk/src/main/decaf/util/concurrent/Future.h
Added: activemq/activemq-cpp/trunk/src/main/decaf/util/concurrent/Future.h
URL:
http://svn.apache.org/viewvc/activemq/activemq-cpp/trunk/src/main/decaf/util/concurrent/Future.h?rev=692895&view=auto
==============================================================================
--- activemq/activemq-cpp/trunk/src/main/decaf/util/concurrent/Future.h (added)
+++ activemq/activemq-cpp/trunk/src/main/decaf/util/concurrent/Future.h Sun Sep
7 09:32:01 2008
@@ -0,0 +1,105 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _DECAF_UTIL_CONCURRENT_FUTURE_H_
+#define _DECAF_UTIL_CONCURRENT_FUTURE_H_
+
+namespace decaf {
+namespace util {
+namespace concurrent {
+
+ /**
+ * A Future represents the result of an asynchronous computation. Methods
+ * are provided to check if the computation is complete, to wait for its
+ * completion, and to retrieve the result of the computation. The result
+ * can only be retrieved using method get when the computation has
+ * completed, blocking if necessary until it is ready. Cancellation is
+ * performed by the cancel method. Additional methods are provided to
+ * determine if the task completed normally or was canceled. Once a
+ * computation has completed, the computation cannot be canceled. If you
+ * would like to use a Future for the sake of cancellability but not
+ * provide a usable result, you can declare types of the form Future<void*>
+ * and return null as a result of the underlying task.
+ */
+ template<typename V>
+ class Future {
+ public:
+
+ virtual ~Future() {}
+
+ /**
+ * Attempts to cancel execution of this task. This attempt will fail
if the
+ * task has already completed, has already been canceled, or could not
be
+ * canceled for some other reason. If successful, and this task has not
+ * started when cancel is called, this task should never run. If the
task
+ * has already started, then the mayInterruptIfRunning parameter
determines
+ * whether the thread executing this task should be interrupted in an
attempt
+ * to stop the task.
+ * <p>
+ * After this method returns, subsequent calls to isDone() will always
return
+ * true. Subsequent calls to isCancelled() will always return true if
this
+ * method returned true.
+ * <p>
+ * @param mayInterruptIfRunning - true if the thread executing this
task should
+ * be interrupted; otherwise, in-progress tasks are allowed to
complete.
+ * @returns false if the task could not be canceled, typically because
it has
+ * already completed normally; true otherwise
+ */
+ bool cancel( bool mayInterruptIfRunning ) = 0;
+
+ /**
+ * Returns true if this task was canceled before it completed normally.
+ * @returns true if this task was canceled before it completed
+ */
+ bool isCancelled() const = 0;
+
+ /**
+ * Returns true if this task completed. Completion may be due to
normal termination,
+ * an exception, or cancellation -- in all of these cases, this method
will return
+ * true.
+ * @returns true if this task completed
+ */
+ bool isDone() const = 0;
+
+ /**
+ * Waits if necessary for the computation to complete, and then
retrieves its result.
+ * @returns the computed result.
+ * @throws CancellationException - if the computation was canceled
+ * @throws ExecutionException - if the computation threw an exception
+ * @throws InterruptedException - if the current thread was
interrupted while waiting
+ */
+ V get() throw( CancellationException, InterruptedException,
ExecutionException ) = 0;
+
+ /**
+ * Waits if necessary for at most the given time for the computation
to complete, and
+ * then retrieves its result, if available.
+ * @param timeout - the maximum time to wait
+ * @param unit - the time unit of the timeout argument
+ * @returns the computed result
+ * @throws CancellationException - if the computation was canceled
+ * @throws ExecutionException - if the computation threw an exception
+ * @throws InterruptedException - if the current thread was
interrupted while waiting
+ * @throws TimeoutException - if the wait timed out
+ */
+ V get( long long timeout, TimeUnit unit)
+ throw( InterruptedException, ExecutionException, TimeoutException
) = 0;
+
+ };
+
+}}}
+
+#endif /*_DECAF_UTIL_CONCURRENT_FUTURE_H_*/
