src/main/decaf/util/concurrent/Semaphore.h

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/*
 * 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_SEMAPHORE_H_
#define _DECAF_UTIL_CONCURRENT_SEMAPHORE_H_

#include <decaf/util/Config.h>

#include <decaf/lang/exceptions/InterruptedException.h>
#include <decaf/lang/exceptions/RuntimeException.h>
#include <decaf/lang/exceptions/IllegalArgumentException.h>

#include <decaf/util/Collection.h>
#include <decaf/util/concurrent/TimeUnit.h>

namespace decaf {
namespace util {
namespace concurrent {

    class SemSync;

    class DECAF_API Semaphore {
    private:

        SemSync* sync;

    private:

        Semaphore( const Semaphore& );
        Semaphore& operator= ( const Semaphore& );

    public:

        Semaphore( int permits );

        Semaphore( int permits, bool fair );

        virtual ~Semaphore();

        void acquire();

        void acquireUninterruptibly();

        bool tryAcquire();

        bool tryAcquire( long long timeout, const TimeUnit& unit );

        void release();

        void acquire( int permits );

        void acquireUninterruptibly( int permits );

        bool tryAcquire( int permits );

        bool tryAcquire( int permits, long long timeout, const TimeUnit& unit );

        void release( int permits );

        int availablePermits() const;

        int drainPermits();

        bool isFair() const;

        std::string toString() const;

        int getQueueLength() const;

        bool hasQueuedThreads() const;

    protected:

        void reducePermits(int reduceBy);

        decaf::util::Collection<decaf::lang::Thread*>* getQueuedThreads() const;

    };

}}}

#endif /* _DECAF_UTIL_CONCURRENT_SEMAPHORE_H_ */

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