target_block Class
The target_block class is an abstract base class that provides basic link management functionality and error checking for target only blocks.
template<class _SourceLinkRegistry, class _MessageProcessorType = ordered_message_processor<typename _SourceLinkRegistry::type::source_type>>
class target_block : public ITarget<typename _SourceLinkRegistry::type::source_type>;
_SourceLinkRegistry
The link registry to be used for holding the source links.
_MessageProcessorType
The processor type for message processing.
| Name | Description |
|---|---|
source_iterator |
The type of the iterator for the source_link_manager for this target_block object. |
| Name | Description |
|---|---|
| target_block | Constructs a target_block object. |
| ~target_block Destructor | Destroys the target_block object. |
| Name | Description |
|---|---|
| propagate | Asynchronously passes a message from a source block to this target block. |
| send | Synchronously passes a message from a source block to this target block. |
| Name | Description |
|---|---|
| async_send | Asynchronously sends a message for processing. |
| decline_incoming_messages | Indicates to the block that new messages should be declined. |
| enable_batched_processing | Enables batched processing for this block. |
| initialize_target | Initializes the base object. Specifically, the message_processor object needs to be initialized. |
| link_source | Links a specified source block to this target_block object. |
| process_input_messages | Processes messages that are received as inputs. |
| process_message | When overridden in a derived class, processes a message that was accepted by this target_block object. |
| propagate_message | When overridden in a derived class, this method asynchronously passes a message from an ISource block to this target_block object. It is invoked by the propagate method, when called by a source block. |
| register_filter | Registers a filter method that will be invoked on every message received. |
| remove_sources | Unlinks all sources after waiting for outstanding asynchronous send operations to complete. |
| send_message | When overridden in a derived class, this method synchronously passes a message from an ISource block to this target_block object. It is invoked by the send method, when called by a source block. |
| sync_send | Synchronously send a message for processing. |
| unlink_source | Unlinks a specified source block from this target_block object. |
| unlink_sources | Unlinks all source blocks from this target_block object. (Overrides ITarget::unlink_sources.) |
| wait_for_async_sends | Waits for all asynchronous propagations to complete. |
target_block
Header: agents.h
Namespace: concurrency
Asynchronously sends a message for processing.
void async_send(_Inout_opt_ message<_Source_type>* _PMessage);
_PMessage
A pointer to the message being sent.
Indicates to the block that new messages should be declined.
void decline_incoming_messages();
This method is called by the destructor to ensure that new messages are declined while destruction is in progress.
Enables batched processing for this block.
void enable_batched_processing();
Initializes the base object. Specifically, the message_processor object needs to be initialized.
void initialize_target(
_Inout_opt_ Scheduler* _PScheduler = NULL,
_Inout_opt_ ScheduleGroup* _PScheduleGroup = NULL);
_PScheduler
The scheduler to be used for scheduling tasks.
_PScheduleGroup
The schedule group to be used for scheduling tasks.
Links a specified source block to this target_block object.
virtual void link_source(_Inout_ ISource<_Source_type>* _PSource);
_PSource
A pointer to the ISource block that is to be linked.
This function should not be called directly on a target_block object. Blocks should be connected together using the link_target method on ISource blocks, which will invoke the link_source method on the corresponding target.
Processes messages that are received as inputs.
virtual void process_input_messages(_Inout_ message<_Source_type>* _PMessage);
_PMessage
A pointer to the message that is to be processed.
When overridden in a derived class, processes a message that was accepted by this target_block object.
virtual void process_message(message<_Source_type> *);
Asynchronously passes a message from a source block to this target block.
virtual message_status propagate(
_Inout_opt_ message<_Source_type>* _PMessage,
_Inout_opt_ ISource<_Source_type>* _PSource);
_PMessage
A pointer to the message object.
_PSource
A pointer to the source block offering the message.
A message_status indication of what the target decided to do with the message.
The method throws an invalid_argument exception if either the _PMessage or _PSource parameter is NULL.
When overridden in a derived class, this method asynchronously passes a message from an ISource block to this target_block object. It is invoked by the propagate method, when called by a source block.
virtual message_status propagate_message(
_Inout_ message<_Source_type>* _PMessage,
_Inout_ ISource<_Source_type>* _PSource) = 0;
_PMessage
A pointer to the message object.
_PSource
A pointer to the source block offering the message.
A message_status indication of what the target decided to do with the message.
Registers a filter method that will be invoked on every message received.
void register_filter(filter_method const& _Filter);
_Filter
The filter method.
Unlinks all sources after waiting for outstanding asynchronous send operations to complete.
void remove_sources();
All target blocks should call this routine to remove the sources in their destructor.
Synchronously passes a message from a source block to this target block.
virtual message_status send(
_Inout_ message<_Source_type>* _PMessage,
_Inout_ ISource<_Source_type>* _PSource);
_PMessage
A pointer to the message object.
_PSource
A pointer to the source block offering the message.
A message_status indication of what the target decided to do with the message.
The method throws an invalid_argument exception if either the _PMessage or _PSource parameter is NULL.
Using the send method outside of message initiation and to propagate messages within a network is dangerous and can lead to deadlock.
When send returns, the message has either already been accepted, and transferred into the target block, or it has been declined by the target.
When overridden in a derived class, this method synchronously passes a message from an ISource block to this target_block object. It is invoked by the send method, when called by a source block.
virtual message_status send_message(
_Inout_ message<_Source_type> *,
_Inout_ ISource<_Source_type> *);
A message_status indication of what the target decided to do with the message.
By default, this block returns declined unless overridden by a derived class.
Synchronously send a message for processing.
void sync_send(_Inout_opt_ message<_Source_type>* _PMessage);
_PMessage
A pointer to the message being sent.
Constructs a target_block object.
target_block();
Destroys the target_block object.
virtual ~target_block();
Unlinks a specified source block from this target_block object.
virtual void unlink_source(_Inout_ ISource<_Source_type>* _PSource);
_PSource
A pointer to the ISource block that is to be unlinked.
Unlinks all source blocks from this target_block object.
virtual void unlink_sources();
Waits for all asynchronous propagations to complete.
void wait_for_async_sends();
This method is used by message block destructors to ensure all asynchronous operations have had time to finish before destroying the block.