ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, > Class Template Reference

A threaded message queueing facility, modeled after the queueing facilities in System V STREAMs which can enqueue multiple messages in one call. More...

#include <Message_Queue_T.h>

Inheritance diagram for ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >:

[legend]Collaboration diagram for ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >:

[legend]List of all members.

Public Member Functions
	ACE_Message_Queue_Ex_N (size_t high_water_mark=ACE_Message_Queue_Base::DEFAULT_HWM, size_t low_water_mark=ACE_Message_Queue_Base::DEFAULT_LWM, ACE_Notification_Strategy *ns=0)
virtual	~ACE_Message_Queue_Ex_N (void)
	Close down the message queue and release all resources.
virtual int	enqueue_head (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *tv=0)
virtual int	enqueue_tail (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *tv=0)
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Protected Member Functions
ACE_Message_Block *	wrap_with_mbs_i (ACE_MESSAGE_TYPE *new_item)

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Detailed Description

template<class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL>
class ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >

A threaded message queueing facility, modeled after the queueing facilities in System V STREAMs which can enqueue multiple messages in one call.

As ACE_Message_Queue_Ex, ACE_Message_Queue_Ex_N is a strongly-typed version of the ACE_Message_Queue. If ACE_SYNCH_DECL is ACE_MT_SYNCH then all operations are thread-safe. Otherwise, if it's ACE_NULL_SYNCH then there's no locking overhead.

The ACE_MESSAGE_TYPE messages that are sent to this queue can be chained. Messages are expected to have a next method that returns the next message in the chain; ACE_Message_Queue_Ex_N uses this method to run through all the incoming messages and enqueue them in one call.

Definition at line 1400 of file Message_Queue_T.h.

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Constructor & Destructor Documentation

template<class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL >

ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >::ACE_Message_Queue_Ex_N	(	size_t	high_water_mark = ACE_Message_Queue_Base::DEFAULT_HWM,
		size_t	low_water_mark = ACE_Message_Queue_Base::DEFAULT_LWM,
		ACE_Notification_Strategy *	ns = 0
	)

Initialize an ACE_Message_Queue_Ex_N. The high_water_mark determines how many bytes can be stored in a queue before it's considered "full." Supplier threads must block until the queue is no longer full. The low_water_mark determines how many bytes must be in the queue before supplier threads are allowed to enqueue additional messages. By default, the high_water_mark equals the low_water_mark, which means that suppliers will be able to enqueue new messages as soon as a consumer removes any message from the queue. Making the low_water_mark smaller than the high_water_mark forces consumers to drain more messages from the queue before suppliers can enqueue new messages, which can minimize the "silly window syndrome."

Definition at line 343 of file Message_Queue_T.cpp.

References ACE_TRACE.

                                 :
    ACE_Message_Queue_Ex<ACE_MESSAGE_TYPE, ACE_SYNCH_USE> (high_water_mark,
                                                           low_water_mark,
                                                           ns)
{
  ACE_TRACE ("ACE_Message_Queue_Ex_N<ACE_MESSAGE_TYPE, ACE_SYNCH_USE>::ACE_Message_Queue_Ex_N");
}

template<class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL >

ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >::~ACE_Message_Queue_Ex_N

(

void

)

[virtual]

Close down the message queue and release all resources.

Definition at line 354 of file Message_Queue_T.cpp.

References ACE_TRACE.

{
  ACE_TRACE ("ACE_Message_Queue_Ex_N<ACE_MESSAGE_TYPE, ACE_SYNCH_USE>::~ACE_Message_Queue_Ex_N");
}

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Member Function Documentation

template<class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL >

int ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >::enqueue_head	(	ACE_MESSAGE_TYPE *	new_item,
		ACE_Time_Value *	tv = 0
	)			[virtual]

Enqueue one or more ACE_MESSAGE_TYPE objects at the head of the queue. If the new_item next() pointer is non-zero, it is assumed to be the start of a series of ACE_MESSAGE_TYPE objects connected via their next() pointers. The series of blocks will be added to the queue in the same order they are passed in as.

Parameters:

	new_item	Pointer to an ACE_MESSAGE_TYPE that will be added to the queue. If the block's next() pointer is non-zero, all blocks chained from the next() pointer are enqueued as well.
	tv	The absolute time the caller will wait until for the block to be queued.

Return values:

	>0	The number of ACE_MESSAGE_TYPE objects on the queue after adding the specified block(s).
	-1	On failure. errno holds the reason. Common errno values are: EWOULDBLOCK: the timeout elapsed ESHUTDOWN: the queue was deactivated or pulsed

Reimplemented from ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_USE >.

Definition at line 361 of file Message_Queue_T.cpp.

References ACE_TRACE, and ACE_Message_Block::release().

{
  ACE_TRACE ("ACE_Message_Queue_Ex_N<ACE_MESSAGE_TYPE, ACE_SYNCH_USE>::enqueue_head");

  // Create a chained ACE_Message_Blocks wrappers around the 'chained'
  // ACE_MESSAGE_TYPES.
  ACE_Message_Block *mb = this->wrap_with_mbs_i (new_item);
  if (0 == mb)
    {
      return -1;
    }

  int result = this->queue_.enqueue_head (mb, timeout);
  if (-1 == result)
    {
      // Zap the messages.
      mb->release ();
    }
  return result;
}

template<class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL >

int ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >::enqueue_tail	(	ACE_MESSAGE_TYPE *	new_item,
		ACE_Time_Value *	tv = 0
	)			[virtual]

Enqueue one or more ACE_MESSAGE_TYPE objects at the tail of the queue. If the new_item next() pointer is non-zero, it is assumed to be the start of a series of ACE_MESSAGE_TYPE objects connected via their next() pointers. The series of blocks will be added to the queue in the same order they are passed in as.

Parameters:

	new_item	Pointer to an ACE_MESSAGE_TYPE that will be added to the queue. If the block's next() pointer is non-zero, all blocks chained from the next() pointer are enqueued as well.
	tv	The absolute time the caller will wait until for the block to be queued.

Return values:

	>0	The number of ACE_MESSAGE_TYPE objects on the queue after adding the specified block(s).
	-1	On failure. errno holds the reason. Common errno values are: EWOULDBLOCK: the timeout elapsed ESHUTDOWN: the queue was deactivated or pulsed

Reimplemented from ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_USE >.

Definition at line 385 of file Message_Queue_T.cpp.

References ACE_TRACE, and ACE_Message_Block::release().

{
  ACE_TRACE ("ACE_Message_Queue_Ex_N<ACE_MESSAGE_TYPE, ACE_SYNCH_USE>::enqueue_tail");

  // Create a chained ACE_Message_Blocks wrappers around the 'chained'
  // ACE_MESSAGE_TYPES.
  ACE_Message_Block *mb = this->wrap_with_mbs_i (new_item);
  if (0 == mb)
    {
      return -1;
    }

  int result = this->queue_.enqueue_tail (mb, timeout);
  if (-1 == result)
    {
      // Zap the message.
      mb->release ();
    }
  return result;
}

template<class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL >

ACE_Message_Block * ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >::wrap_with_mbs_i

(

ACE_MESSAGE_TYPE *

new_item

)

[protected]

An helper method that wraps the incoming chain messages with ACE_Message_Blocks.

Definition at line 409 of file Message_Queue_T.cpp.

References ACE_NEW_NORETURN, ACE_NEW_RETURN, ACE_TRACE, ACE_Message_Block::next(), and ACE_Message_Block::release().

{
  ACE_TRACE ("ACE_Message_Queue_Ex_N<ACE_MESSAGE_TYPE, ACE_SYNCH_USE>::wrap_with_mbs_i");

  // We need to keep a reference to the head of the chain
  ACE_Message_Block *mb_head = 0;

  ACE_NEW_RETURN (mb_head,
                  ACE_Message_Block ((char *) new_item,
                                     sizeof (*new_item),
                                     ACE_Message_Queue_Ex<ACE_MESSAGE_TYPE, ACE_SYNCH_USE>::DEFAULT_PRIORITY),
                  0);

  // mb_tail will point to the last ACE_Message_Block
  ACE_Message_Block *mb_tail = mb_head;

  // Run through rest of the messages and wrap them
  for (ACE_MESSAGE_TYPE *pobj = new_item->next (); pobj; pobj = pobj->next ())
    {
      ACE_Message_Block *mb_temp = 0;
      ACE_NEW_NORETURN (mb_temp,
                        ACE_Message_Block ((char *) pobj,
                                           sizeof (*pobj),
                                           ACE_Message_Queue_Ex<ACE_MESSAGE_TYPE, ACE_SYNCH_USE>::DEFAULT_PRIORITY));
      if (mb_temp == 0)
        {
          mb_head->release ();
          mb_head = 0;
          break;
        }

      mb_tail->next (mb_temp);
      mb_tail = mb_temp;
    }

  return mb_head;
}

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Member Data Documentation

template<class ACE_MESSAGE_TYPE, ACE_SYNCH_DECL >

ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, >::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

Reimplemented from ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_USE >.

Definition at line 1471 of file Message_Queue_T.h.

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The documentation for this class was generated from the following files:

• Message_Queue_T.h
• Message_Queue_T.cpp

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