ACE
6.2.5
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A threaded message queueing facility, modeled after the queueing facilities in System V STREAMs. More...
#include <Message_Queue_T.h>
Public Types | |
enum | { DEFAULT_PRIORITY = 0 } |
typedef ACE_Message_Queue_Ex_Iterator < ACE_MESSAGE_TYPE, ACE_SYNCH_USE, TIME_POLICY > | ITERATOR |
typedef ACE_Message_Queue_Ex_Reverse_Iterator < ACE_MESSAGE_TYPE, ACE_SYNCH_USE, TIME_POLICY > | REVERSE_ITERATOR |
Public Member Functions | |
virtual int | close (void) |
virtual | ~ACE_Message_Queue_Ex (void) |
Releases all resources from the message queue and marks it deactivated. More... | |
virtual int | flush (void) |
virtual int | flush_i (void) |
virtual ACE_SYNCH_MUTEX_T & | lock (void) |
Returns a reference to the lock used by the ACE_Message_Queue_Ex. More... | |
ACE_Time_Value_T< TIME_POLICY > | gettimeofday () |
void | set_time_policy (TIME_POLICY const &time_policy) |
virtual void | dump (void) const |
Dump the state of an object. More... | |
Initialization methods | |
ACE_Message_Queue_Ex (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 int | open (size_t hwm=ACE_Message_Queue_Base::DEFAULT_HWM, size_t lwm=ACE_Message_Queue_Base::DEFAULT_LWM, ACE_Notification_Strategy *=0) |
Enqueue and dequeue methods | |
The enqueue and dequeue methods accept a timeout value passed as an ACE_Time_Value *. In all cases, if the timeout pointer is 0, the caller will block until action is possible. If the timeout pointer is non-zero, the call will wait (if needed, subject to water mark settings) until the absolute time specified in the referenced ACE_Time_Value object is reached. If the time is reached before the desired action is possible, the method will return -1 with errno set to The time parameters are handled the same as in ACE_Message_Queue, so you can see C++NPv2 Section 6.2 and APG Section 12.3 for a fuller treatment of ACE_Message_Queue, enqueueing, dequeueing, and how these operations are affected by queue state transitions. | |
virtual int | peek_dequeue_head (ACE_MESSAGE_TYPE *&first_item, ACE_Time_Value *timeout=0) |
virtual int | enqueue_prio (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *timeout=0, unsigned long priority=DEFAULT_PRIORITY) |
virtual int | enqueue_deadline (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *timeout=0) |
virtual int | enqueue (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *timeout=0) |
virtual int | enqueue_tail (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *timeout=0) |
virtual int | enqueue_head (ACE_MESSAGE_TYPE *new_item, ACE_Time_Value *timeout=0) |
virtual int | dequeue (ACE_MESSAGE_TYPE *&first_item, ACE_Time_Value *timeout=0) |
This method is an alias for the following <dequeue_head> method. More... | |
virtual int | dequeue_head (ACE_MESSAGE_TYPE *&first_item, ACE_Time_Value *timeout=0) |
virtual int | dequeue_prio (ACE_MESSAGE_TYPE *&dequeued, ACE_Time_Value *timeout=0) |
virtual int | dequeue_tail (ACE_MESSAGE_TYPE *&dequeued, ACE_Time_Value *timeout=0) |
virtual int | dequeue_deadline (ACE_MESSAGE_TYPE *&dequeued, ACE_Time_Value *timeout=0) |
Queue statistics methods | |
virtual bool | is_full (void) |
True if queue is full, else false. More... | |
virtual bool | is_empty (void) |
True if queue is empty, else false. More... | |
virtual size_t | message_bytes (void) |
virtual size_t | message_length (void) |
virtual size_t | message_count (void) |
virtual void | message_bytes (size_t new_size) |
virtual void | message_length (size_t new_length) |
Water mark (flow control) methods | |
virtual size_t | high_water_mark (void) |
virtual void | high_water_mark (size_t hwm) |
virtual size_t | low_water_mark (void) |
virtual void | low_water_mark (size_t lwm) |
Activation and queue state methods | |
See C++NPv2 Section 6.2 and APG Section 12.3 for a fuller treatment of queue states and transitions and how the transitions affect message enqueueing and dequeueing operations. | |
virtual int | deactivate (void) |
virtual int | activate (void) |
virtual int | pulse (void) |
virtual int | state (void) |
virtual int | deactivated (void) |
Notification strategy methods | |
virtual int | notify (void) |
virtual ACE_Notification_Strategy * | notification_strategy (void) |
Get the notification strategy for the <Message_Queue> More... | |
virtual void | notification_strategy (ACE_Notification_Strategy *s) |
Set the notification strategy for the <Message_Queue> More... | |
Public Attributes | |
ACE_ALLOC_HOOK_DECLARE | |
Declare the dynamic allocation hooks. More... | |
Protected Attributes | |
ACE_Message_Queue < ACE_SYNCH_USE, TIME_POLICY > | queue_ |
Implement this via an ACE_Message_Queue. More... | |
Friends | |
class | ACE_Message_Queue_Ex_Iterator< ACE_MESSAGE_TYPE, ACE_SYNCH_USE, TIME_POLICY > |
class | ACE_Message_Queue_Ex_Reverse_Iterator< ACE_MESSAGE_TYPE, ACE_SYNCH_USE, TIME_POLICY > |
A threaded message queueing facility, modeled after the queueing facilities in System V STREAMs.
ACE_Message_Queue_Ex is a strongly-typed version of the ACE_Message_Queue class. Rather than queueing in terms of ACE_Message_Block objects, ACE_Message_Queue_Ex has a template argument to specify the type of objects that are queued.
The second template argument parameterizes the queue's synchronization. The argument specifies a synchronization strategy. The two main strategies available for ACE_SYNCH_DECL are:
typedef ACE_Message_Queue_Ex_Iterator<ACE_MESSAGE_TYPE, ACE_SYNCH_USE, TIME_POLICY> ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >::ITERATOR |
typedef ACE_Message_Queue_Ex_Reverse_Iterator<ACE_MESSAGE_TYPE, ACE_SYNCH_USE, TIME_POLICY> ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >::REVERSE_ITERATOR |
anonymous enum |
ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >::ACE_Message_Queue_Ex | ( | size_t | high_water_mark = ACE_Message_Queue_Base::DEFAULT_HWM , |
size_t | low_water_mark = ACE_Message_Queue_Base::DEFAULT_LWM , |
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ACE_Notification_Strategy * | ns = 0 |
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Initialize an ACE_Message_Queue_Ex.
high_water_mark | 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. |
low_water_mark | Low water mark. Determines how many bytes must be in the queue before supplier threads are allowed to enqueue additional data. By default, the hwm equals lwm, 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." |
ns | Notification strategy. Pointer to an object conforming to the ACE_Notification_Strategy interface. If set, the object's notify(void) method will be called each time data is added to this ACE_Message_Queue. |
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Releases all resources from the message queue and marks it deactivated.
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Reactivate the queue so that threads can enqueue and dequeue messages again. Returns the state of the queue before the call.
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Releases all resources from the message queue and marks it deactivated.
The | number of messages released from the queue; -1 on error. |
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Deactivate the queue and wakeup all threads waiting on the queue so they can continue. No messages are removed from the queue, however. Any other operations called until the queue is activated again will immediately return -1 with errno
== ESHUTDOWN. Returns WAS_INACTIVE if queue was inactive before the call and WAS_ACTIVE if queue was active before the call.
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Returns true if the state of the queue is DEACTIVATED, but false if the queue's state is ACTIVATED or PULSED.
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This method is an alias for the following <dequeue_head> method.
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Because there's deadline associated with enqueue_deadline(), this method will behave just as dequeue_head().
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Dequeue the item at the head of the queue and return a pointer to it.
first_item | Reference to an ACE_MESSAGE_TYPE * that will be set to the address of the dequeued item. |
timeout | The absolute time the caller will wait until for an item to be dequeued. |
>=0 | The number of items remaining in the queue. |
-1 | On failure. errno holds the reason. Common errno values are:
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Dequeue the item that has the lowest priority (preserves FIFO order for items with the same priority) and return a pointer to it.
dequeued | Reference to an ACE_MESSAGE_TYPE * that will be set to the address of the dequeued item. |
timeout | The absolute time the caller will wait until for an item to be dequeued. |
>=0 | The number of items remaining in the queue. |
-1 | On failure. errno holds the reason. Common errno values are:
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Dequeue the item at the tail of the queue and return a pointer to it.
dequeued | Reference to an ACE_MESSAGE_TYPE * that will be set to the address of the dequeued item. |
timeout | The absolute time the caller will wait until for an item to be dequeued. |
>=0 | The number of items remaining in the queue. |
-1 | On failure. errno holds the reason. Common errno values are:
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Dump the state of an object.
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This method acts just like enqueue_tail(). There's no deadline time associated with items.
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Enqueue an item at the head of the queue.
new_item | Pointer to an item that will be added to the queue. |
timeout | The absolute time the caller will wait until for the item to be queued. |
>0 | The number of items on the queue after adding the specified item. |
-1 | On failure. errno holds the reason. Common errno values are:
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Reimplemented in ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >.
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Enqueue an ACE_MESSAGE TYPE into the queue in accordance with the specified priority (0 is lowest priority). FIFO order is maintained when items of the same priority are inserted consecutively.
new_item | Pointer to an item that will be added to the queue. |
timeout | The absolute time the caller will wait until for the block to be queued. |
priority | The priority to use when enqueueing the item. |
>0 | The number of items on the queue after adding the specified item. |
-1 | On failure. errno holds the reason. Common errno values are:
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Enqueue an item at the tail of the queue.
new_item | Pointer to an item that will be added to the queue. |
timeout | The absolute time the caller will wait until for the item to be queued. |
>0 | The number of items on the queue after adding the specified item. |
-1 | On failure. errno holds the reason. Common errno values are:
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Reimplemented in ACE_Message_Queue_Ex_N< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >.
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Releases all resources from the message queue but does not mark it deactivated. This method holds the queue lock during this operation.
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Release all resources from the message queue but do not mark it as deactivated.
ACE_Time_Value_T<TIME_POLICY> ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >::gettimeofday | ( | ) |
Get the current time of day according to the queue's TIME_POLICY. Allows users to initialize timeout
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Get high watermark.
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Set the high watermark, which determines how many bytes can be stored in a queue before it's considered "full."
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True if queue is empty, else false.
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True if queue is full, else false.
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Returns a reference to the lock used by the ACE_Message_Queue_Ex.
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Get low watermark.
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Set the low watermark, which determines how many bytes must be in the queue before supplier threads are allowed to enqueue additional <ACE_MESSAGE_TYPE>s.
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Number of total bytes on the queue, i.e., sum of the message block sizes.
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New value of the number of total bytes on the queue, i.e., sum of the message block sizes.
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Number of total messages on the queue.
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Number of total length on the queue, i.e., sum of the message block lengths.
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New value of the number of total length on the queue, i.e., sum of the message block lengths.
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Get the notification strategy for the <Message_Queue>
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Set the notification strategy for the <Message_Queue>
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This hook is automatically invoked by <enqueue_head>, <enqueue_tail>, and <enqueue_prio> when a new item is inserted into the queue. Subclasses can override this method to perform specific notification strategies (e.g., signaling events for a <WFMO_Reactor>, notifying a <Reactor>, etc.). In a multi-threaded application with concurrent consumers, there is no guarantee that the queue will be still be non-empty by the time the notification occurs.
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Initialize an ACE_Message_Queue_Ex.
high_water_mark | 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. |
low_water_mark | Low water mark. Determines how many bytes must be in the queue before supplier threads are allowed to enqueue additional data. By default, the hwm equals lwm, 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." |
ns | Notification strategy. Pointer to an object conforming to the ACE_Notification_Strategy interface. If set, the object's notify(void) method will be called each time data is added to this ACE_Message_Queue. |
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Retrieve a pointer to the first item in the queue without removing it.
first_item | Reference to an ACE_MESSAGE_TYPE * that will point to the first item on the queue. The item remains on the queue until this or another thread dequeues it. |
timeout | The absolute time the caller will wait until for an item to be queued. |
>0 | The number of items on the queue. |
-1 | On failure. errno holds the reason. Common errno values are:
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Pulse the queue to wake up any waiting threads. Changes the queue state to PULSED; future enqueue/dequeue operations proceed as in ACTIVATED state.
The | queue's state before this call. |
void ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >::set_time_policy | ( | TIME_POLICY const & | time_policy | ) |
Allows applications to control how the timer queue gets the time of day.
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Returns the current state of the queue, which can be one of ACTIVATED, DEACTIVATED, or PULSED.
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ACE_Message_Queue_Ex< ACE_MESSAGE_TYPE, ACE_SYNCH_DECL, TIME_POLICY >::ACE_ALLOC_HOOK_DECLARE |
Declare the dynamic allocation hooks.
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Implement this via an ACE_Message_Queue.