| /* |
| * 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_EXECUTOR_H_ |
| #define _DECAF_UTIL_CONCURRENT_EXECUTOR_H_ |
| |
| #include <decaf/util/Config.h> |
| |
| #include <decaf/lang/Runnable.h> |
| #include <decaf/lang/exceptions/NullPointerException.h> |
| #include <decaf/util/concurrent/RejectedExecutionException.h> |
| |
| namespace decaf { |
| namespace util { |
| namespace concurrent { |
| |
| /** |
| * An object that executes submitted {@link decaf.lang.Runnable} tasks. This |
| * interface provides a way of decoupling task submission from the |
| * mechanics of how each task will be run, including details of thread |
| * use, scheduling, etc. An <tt>Executor</tt> is normally used |
| * instead of explicitly creating threads. For example, rather than |
| * invoking <tt>new Thread(new(RunnableTask())).start()</tt> for each |
| * of a set of tasks, you might use: |
| * |
| * <pre> |
| * Executor executor = <em>anExecutor</em>; |
| * executor->execute( new RunnableTask1() ); |
| * executor->execute( new RunnableTask2() ); |
| * ... |
| * </pre> |
| * |
| * However, the <tt>Executor</tt> interface does not strictly |
| * require that execution be asynchronous. In the simplest case, an |
| * executor can run the submitted task immediately in the caller's |
| * thread: |
| * |
| * <pre> |
| * class DirectExecutor : public Executor { |
| * public: |
| * |
| * void execute( Runnable* r ) { |
| * r->run(); |
| * } |
| * |
| * }</pre> |
| * |
| * More typically, tasks are executed in some thread other |
| * than the caller's thread. The executor below spawns a new thread |
| * for each task. |
| * |
| * <pre> |
| * class ThreadPerTaskExecutor : public Executor { |
| * public: |
| * std::vector<Thread*gt; threads; |
| * |
| * void execute( Runnable* r ) { |
| * threads.push_back( new Thread( r ) ); |
| * threads.rbegin()->start(); |
| * } |
| * |
| * }</pre> |
| * |
| * The <tt>Executor</tt> implementations provided in this package |
| * implement {@link decaf.util.concurrent.ExecutorService}, which is a more |
| * extensive interface. The {@link decaf.util.concurrent.ThreadPoolExecutor} |
| * class provides an extensible thread pool implementation. The |
| * {@link decaf.util.concurrent.Executor} class provides convenient factory |
| * methods for these Executors. |
| * |
| * @since 1.0 |
| */ |
| class DECAF_API Executor { |
| public: |
| |
| virtual ~Executor() {} |
| |
| /** |
| * This method is the same as calling the two param execute method and passing |
| * true as the second argument. |
| * |
| * @param command |
| * The runnable task to be executed. |
| * |
| * @throws RejectedExecutionException if this task cannot be |
| * accepted for execution. |
| * |
| * @throws NullPointerException if command is null |
| */ |
| virtual void execute(decaf::lang::Runnable* command) = 0; |
| |
| /** |
| * Executes the given command at some time in the future. The command |
| * may execute in a new thread, in a pooled thread, or in the calling |
| * thread, at the discretion of the <tt>Executor</tt> implementation. |
| * |
| * @param command |
| * The runnable task to be executed. |
| * @param takeOwnership |
| * Indicates if the Executor should assume ownership of the task and |
| * delete the pointer once the task has completed. |
| * |
| * @throws RejectedExecutionException if this task cannot be |
| * accepted for execution. |
| * |
| * @throws NullPointerException if command is null |
| */ |
| virtual void execute(decaf::lang::Runnable* command, bool takeOwnership) = 0; |
| |
| }; |
| |
| }}} |
| |
| #endif /* _DECAF_UTIL_CONCURRENT_EXECUTOR_H_ */ |