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#ifndef _posix_EventChannelThreads_h
#define _sys_EventChannelThreads_h
/*
*
* Copyright (c) 2006 The Apache Software Foundation
*
* Licensed 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 "EventChannel.h"
#include "qpid/Exception.h"
#include "qpid/sys/AtomicCount.h"
#include "qpid/sys/Monitor.h"
#include "qpid/sys/Thread.h"
#include "qpid/sys/Time.h"
#include "qpid/sys/Runnable.h"
#include <vector>
namespace qpid {
namespace sys {
/**
Dynamic thread pool serving an EventChannel.
Threads run a loop { e = wait(); e->dispatch(); }
The size of the thread pool is automatically adjusted to optimal size.
*/
class EventChannelThreads :
public qpid::SharedObject<EventChannelThreads>,
private sys::Runnable
{
public:
/** Constant to represent an unlimited number of threads */
static const size_t unlimited;
/**
* Create the thread pool and start initial threads.
* @param minThreads Pool will initialy contain minThreads threads and
* will never shrink to less until shutdown.
* @param maxThreads Pool will never grow to more than maxThreads.
*/
static EventChannelThreads::shared_ptr create(
EventChannel::shared_ptr channel = EventChannel::create(),
size_t minThreads = 1,
size_t maxThreads = unlimited
);
~EventChannelThreads();
/** Post event to the underlying channel */
void post(Event& event) { channel->post(event); }
/**
* Terminate all threads.
*
* Returns immediately, use join() to wait till all threads are
* shut down.
*/
void shutdown();
/** Wait for all threads to terminate. */
void join();
private:
typedef std::vector<sys::Thread> Threads;
typedef enum {
RUNNING, TERMINATING, JOINING, SHUTDOWN
} State;
EventChannelThreads(
EventChannel::shared_ptr channel, size_t min, size_t max);
void addThread();
void run();
bool keepRunning();
void adjustThreads();
Monitor monitor;
size_t minThreads;
size_t maxThreads;
EventChannel::shared_ptr channel;
Threads workers;
sys::AtomicCount nWaiting;
State state;
};
}}
#endif /*!_sys_EventChannelThreads_h*/
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