TAO_LF_Event Class Reference

Use the Leader/Follower loop to wait for one specific event. More...

#include <LF_Event.h>

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List of all members.

State management

A Leader/Followers event goes through several states during its lifetime. We use an enum to represent those states and state changes are validated according to the rules defined in the concrete classes. We treat the states as finite states in a FSM. The possible sequence of states through which the FSM migrates is defined in the concrete classes.

enum  {
  LFS_IDLE = 0, LFS_ACTIVE, LFS_CONNECTION_WAIT, LFS_SUCCESS,
  LFS_FAILURE, LFS_TIMEOUT, LFS_CONNECTION_CLOSED
}
void state_changed (int new_state)
virtual int successful (void) const =0
virtual int error_detected (void) const =0
int keep_waiting (void)
 Check if we should keep waiting.

Public Member Functions

 TAO_LF_Event (void)
 Constructor.
virtual ~TAO_LF_Event (void)
 Destructor.
int bind (TAO_LF_Follower *follower)
 Bind a follower.
int unbind (void)
 Unbind the follower.
void reset_state (int new_state)
 Reset the state, irrespective of the previous states.

Protected Member Functions

virtual void state_changed_i (int new_state)=0
 Validate the state change.
virtual int is_state_final (void)=0
 Check whether we have reached the final state..

Protected Attributes

int state_
 The current state.
TAO_LF_Followerfollower_
 The bounded follower.

Private Member Functions

virtual void set_state (int new_state)
 Set the state irrespective of anything.

Friends

class TAO_Leader_Follower

Detailed Description

Use the Leader/Follower loop to wait for one specific event.

The Leader/Follower event loop is used to wait for incoming responses, as well as to wait for all the data to be flushed. This class encapsulates this event loop. It uses Template Method to parametrize the 'waited for' predicate (i.e. reply received or message sent or connection establishment etc.)

Todo:
Implementing the Leader/Followers loop in this class, as well as the callbacks to communicate that an event has completed leads to excessive coupling. A better design would use a separate class to signal the events, that would allow us to remove the Leader/Followers logic from the ORB. However, that requires other major changes and it somewhat complicates the design.


Member Enumeration Documentation

anonymous enum
 

Enumerator:
LFS_IDLE  The event is created, and is in initial state.
LFS_ACTIVE  The event is active.
LFS_CONNECTION_WAIT  The event is waiting for connection completion.
LFS_SUCCESS  The event has completed successfully.
LFS_FAILURE  A failure has been detected while the event was active.
LFS_TIMEOUT  The event has timed out.
LFS_CONNECTION_CLOSED  The connection was closed.


Constructor & Destructor Documentation

TAO_LF_Event::TAO_LF_Event void   ) 
 

Constructor.

TAO_LF_Event::~TAO_LF_Event void   )  [virtual]
 

Destructor.


Member Function Documentation

ACE_INLINE int TAO_LF_Event::bind TAO_LF_Follower follower  ) 
 

Bind a follower.

An event can be waited on by at most one follower thread, this method is used to bind the waiting thread to the event, in order to let the event signal any important state changes.

Returns:
-1 if the LF_Event is already bound, 0 otherwise

virtual int TAO_LF_Event::error_detected void   )  const [pure virtual]
 

Return 1 if an error was detected while waiting for the event

Implemented in TAO_LF_CH_Event, and TAO_LF_Invocation_Event.

virtual int TAO_LF_Event::is_state_final void   )  [protected, pure virtual]
 

Check whether we have reached the final state..

Implemented in TAO_LF_CH_Event, and TAO_LF_Invocation_Event.

ACE_INLINE int TAO_LF_Event::keep_waiting void   ) 
 

Check if we should keep waiting.

ACE_INLINE void TAO_LF_Event::reset_state int  new_state  ) 
 

Reset the state, irrespective of the previous states.

Reimplemented in TAO_LF_CH_Event.

void TAO_LF_Event::set_state int  new_state  )  [private, virtual]
 

Set the state irrespective of anything.

Reimplemented in TAO_LF_CH_Event.

void TAO_LF_Event::state_changed int  new_state  ) 
 

Accessor to change the state. The state isnt changed unless certain conditions are satisfied.

virtual void TAO_LF_Event::state_changed_i int  new_state  )  [protected, pure virtual]
 

Validate the state change.

Implemented in TAO_LF_CH_Event, and TAO_LF_Invocation_Event.

virtual int TAO_LF_Event::successful void   )  const [pure virtual]
 

Return 1 if the condition was satisfied successfully, 0 if it has not

Implemented in TAO_LF_CH_Event, and TAO_LF_Invocation_Event.

ACE_INLINE int TAO_LF_Event::unbind void   ) 
 

Unbind the follower.


Friends And Related Function Documentation

friend class TAO_Leader_Follower [friend]
 


Member Data Documentation

TAO_LF_Follower* TAO_LF_Event::follower_ [protected]
 

The bounded follower.

int TAO_LF_Event::state_ [protected]
 

The current state.


The documentation for this class was generated from the following files:
Generated on Wed Nov 23 16:03:09 2005 for TAO by  doxygen 1.4.5