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#ifndef SERIALIZER_H
#define SERIALIZER_H
/*
*
* 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.
*
*/
#include "qpid/sys/Runnable.h"
#include "qpid/sys/Monitor.h"
#include "qpid/sys/Thread.h"
#include <boost/function.hpp>
#include <boost/noncopyable.hpp>
#include <deque>
namespace qpid {
namespace sys {
/**
* Execute tasks sequentially, queuing tasks when necessary to
* ensure only one thread at a time executes a task and tasks
* are executed in order.
*/
class Serializer : private boost::noncopyable, private Runnable
{
public:
typedef boost::function<void()> Task;
/** Start a serializer.
*
* @param notifyDispatch Called when work is pending and there is no
* active dispatch thread. Must arrange for dispatch() to be called
* in some thread other than the calling thread and return.
* By default the Serializer supplies its own dispatch thread.
*
* @param immediate Allow execute() to execute a task immediatly
* in the current thread.
*/
Serializer(bool immediate=true, Task notifyDispatch=Task());
~Serializer();
/**
* Task may be executed immediately in the calling thread if there
* are no other tasks pending or executing and the "immediate"
* paramater to the constructor was true. Otherwise task will be
* enqueued for execution by a dispatch thread.
*/
void execute(Task& task);
/** Execute pending tasks sequentially in calling thread.
* Drains the task queue and returns, does not block for more tasks.
*
* @exception ShutdownException if the serializer is being destroyed.
*/
void dispatch();
private:
enum State {
IDLE, ///< No threads are active.
EXECUTING, ///< execute() is executing a single task.
DISPATCHING, ///< dispatch() is draining the queue.
SHUTDOWN ///< Serializer is being destroyed.
};
void dispatch(Task&);
void notifyWorker();
void run();
Monitor lock;
State state;
bool immediate;
std::deque<Task> queue;
Thread worker;
Task notifyDispatch;
};
}} // namespace qpid::sys
#endif /*!SERIALIZER_H*/
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