ThreadGroup.h

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/*
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   The MIT License

   Copyright (c) 2009 Scientific Computing and Imaging Institute,
   University of Utah.

   
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///
///@file   ThreadGroup.h
///@brief  A set of threads
///
///@author Steve Parker
///        Department of Computer Science
///        University of Utah
///@date   June 1997
///

#ifndef Core_Thread_ThreadGroup_h
#define Core_Thread_ThreadGroup_h

#include <Core/Thread/Legacy/Mutex.h>

#include <vector>

#include <Core/Thread/Legacy/share.h>

namespace SCIRun {

class Thread;

/**************************************
 
@class
   ThreadGroup
   
KEYWORDS
   Thread
   
@details
   A group of threads that are linked together for scheduling
   and control purposes.  The threads may be stopped, resumed
   and alerted simultaneously.
 
****************************************/
    class SCISHARE ThreadGroup {
    public:
        
        //////////
        /// Create a thread group with the specified <i>name</i>.
        /// <i>parentGroup</i> specifies the parent <b>ThreadGroup</b>
        /// which defaults to the default top-level group.
        ThreadGroup(const char* name, ThreadGroup* parentGroup=0);
        
        //////////
        /// Destroy the thread group.  All of the running threads
        /// should be stopped before the <b>ThreadGroup</b> is destroyed.
        ~ThreadGroup();
        
        //////////
        /// Return a snapshot of the number of living threads.  If
        /// <i>countDaemon</i> is true, then daemon threads will be
        /// included in the count.
        int numActive(bool countDaemon);
        
        //////////
        /// Stop all of the threads in this thread group
        void stop();
        
        //////////
        /// Resume all of the threads in this thread group
        void resume();
        
        //////////
        /// Wait until all of the threads have completed.
        void join();
        
        //////////
        /// Detach the thread, joins are no longer possible.
        void detach();
        
        //////////
        /// Return the parent <b>ThreadGroup.</b>  Returns null if
        /// this is the default threadgroup.
        ThreadGroup* parentGroup();
        
        //////////
        /// Arrange to have the threadGroup gang scheduled, so that
        /// all of the threads will be executing at the same time if
        /// multiprocessing resources permit.  This interface will
        /// typically be employed by the <i>Thread::parallel</i>
        /// static method, and will typically not be called directly
        /// by user code.  Threads added to the group after this call
        /// may or may not be included in the schedule gang. 
        void gangSchedule();

    protected:
        friend class Thread;
        static ThreadGroup* s_default_group;

    private:
        Mutex lock_;
        const char* name_;
        ThreadGroup* parent_;
        std::vector<ThreadGroup*> groups_;
        std::vector<Thread*> threads_;
        void addme(ThreadGroup* t);
        void addme(Thread* t);

        // Cannot copy them
        ThreadGroup(const ThreadGroup&);
        ThreadGroup& operator=(const ThreadGroup&);
    };
} // End namespace SCIRun

#endif