RWTPCValQueuePrioritized< Type > Class Template Reference

First-in-first-out (FIFO) queue that provides producer-consumer synchronization semantics for exchanging prioritized values between cooperating threads. More...

#include <rw/itc/RWTPCValQueuePrioritized.h>

Inheritance diagram for RWTPCValQueuePrioritized< Type >:

Public Member Functions
	RWTPCValQueuePrioritized (size_t maxCapacity=0, bool isOpen=true)
	~RWTPCValQueuePrioritized (void)
Public Member Functions inherited from RWTPCValBufferBasePrioritized< Type, RWTPriorityDecorator< Type > >
virtual	~RWTPCValBufferBasePrioritized (void)
bool	tryWrite (long priority, const Type &value)
void	write (long priority, const Type &value)
RWWaitStatus	write (long priority, const Type &value, unsigned long milliseconds)
Public Member Functions inherited from RWTPCValBufferBaseDecorated< Type, RWTPriorityDecorator< Type > >
virtual	~RWTPCValBufferBaseDecorated (void)
Type	peek (void)
RWWaitStatus	peek (Type &result, unsigned long milliseconds)
Type	read (void)
RWWaitStatus	read (Type &result, unsigned long milliseconds)
bool	tryPeek (Type &result)
bool	tryRead (Type &result)
bool	tryWrite (const Type &value)
void	write (const Type &value)
RWWaitStatus	write (const Type &value, unsigned long milliseconds)

Additional Inherited Members
Protected Member Functions inherited from RWTPCValBufferBase< RWTPriorityDecorator< Type > >
virtual	~RWTPCValBufferBase (void)
RWTPriorityDecorator< Type >	peek (void)
RWWaitStatus	peek (RWTPriorityDecorator< Type > &result, unsigned long milliseconds)
RWTPriorityDecorator< Type >	read (void)
RWWaitStatus	read (RWTPriorityDecorator< Type > &result, unsigned long milliseconds)
bool	tryPeek (RWTPriorityDecorator< Type > &result)
bool	tryRead (RWTPriorityDecorator< Type > &result)
bool	tryWrite (const RWTPriorityDecorator< Type > &value)
void	write (const RWTPriorityDecorator< Type > &value)
RWWaitStatus	write (const RWTPriorityDecorator< Type > &value, unsigned long milliseconds)

Detailed Description

template<class Type>
class RWTPCValQueuePrioritized< Type >

RWTPCValQueuePrioritized<Type> is a first-in-first-out (FIFO) queue that provides producer-consumer synchronization semantics for exchanging prioritized values between cooperating threads.

In the producer-consumer synchronization model, reader threads (consumers) are blocked while the queue is empty, and writer threads (producers) are blocked while the queue is full. The queue is considered full when the number of unread entries equals or exceeds some user-specified maximum capacity.

The write operations inherited by this class bind a priority value to each data value prior to storing that value in an internal buffer. The priority value is used by these write operations to determine a value's insertion point within the queue, such that the set of unread values will be retrieved in priority order when they are eventually read from the queue. A new value is retrieved after any previously inserted values of the same priority.

Example

#include <rw/itc/RWTPCValQueuePrioritized.h>
#include <rw/thread/RWThreadFunction.h>
#include <rw/cstring.h>
#include <iostream>

RWTPCValQueuePrioritized<RWCString> pcQueue;

void reader(void)
{
    // Get values from queue and write to stdout.
    RWCString message;
    while ("Exit" != (message = pcQueue.read())) {
        std::cout << message << std::endl;
        rwSleep(100); // Let the messages pile up
    }
    std::cout << "EXIT" << std::endl;
}

int main()
{
    RWThread thread = RWThreadFunction::make(reader);
    RWCString high("High"), medium("Medium"), low("Low");

    thread.start();
    pcQueue.write(1, low);
    pcQueue.write(1, low);
    pcQueue.write(2, medium);
    pcQueue.write(1, low);
    pcQueue.write(3, high);
    pcQueue.write(2, medium);
    pcQueue.write(1, low);
    pcQueue.write(1, low);
    pcQueue.write(3, high);
    pcQueue.write(1, low);
    pcQueue.write(2, medium);
    pcQueue.write(2, medium);
    pcQueue.write(0, "Exit");
    thread.join();
    return 0;
}

OUTPUT:

High
High
Medium
Medium
Medium
Medium
Low
Low
Low
Low
Low
EXIT

Constructor & Destructor Documentation

template<class Type >

RWTPCValQueuePrioritized< Type >::RWTPCValQueuePrioritized ( size_t  maxCapacity = 0, bool  isOpen = true  )

inline

Constructs a value-based, prioritized, producer-consumer queue instance.

The parameter maxCapacity specifies the maximum number of unread entries to allow to accumulate within the queue. Once the number of entries in the queue equals this number, any thread attempting to write an additional entry is blocked until an entry is removed by a read operation, or until the capacity is increased. A capacity of zero, the default, indicates that the queue has no size limit, except as imposed by memory limitations, and that all write operations should complete without blocking.

The parameter isOpen is a bool value that specifies whether the queue should be initialized in the open state, true, the default, or the closed state, false.

template<class Type >

RWTPCValQueuePrioritized< Type >::~RWTPCValQueuePrioritized ( void  )

inline

Destructor.