Interface for the application of events, them being packets or log events. More...

#include <pipeline_interfaces.h>

Inheritance diagram for Event_handler:

Public Member Functions
	Event_handler ()

virtual	~Event_handler ()=default

virtual int	initialize ()=0
	Initialization as defined in the handler implementation. More...

virtual int	terminate ()=0
	Terminate the execution as defined in the handler implementation. More...

virtual int	handle_event (Pipeline_event event, Continuation continuation)=0
	Handling of an event as defined in the handler implementation. More...

virtual int	handle_action (Pipeline_action *action)=0
	Handling of an action as defined in the handler implementation. More...

void	plug_next_handler (Event_handler *next_handler)
	Plug an handler to be the next in line for execution. More...

void	append (Event_handler *last_handler)
	Append an handler to be the last in line for execution. More...

virtual bool	is_unique ()=0
	This method identifies the handler as being unique. More...

virtual int	get_role ()=0
	This method returns the handler role. More...

int	terminate_pipeline ()
	Shutdown and delete all handlers in the pipeline. More...

Static Public Member Functions
static void	append_handler (Event_handler *pipeline, Event_handler event_handler)
	Append an handler to a given pipeline. More...

static void	get_handler_by_role (Event_handler pipeline, int role, Event_handler *event_handler)
	Returns an handler that plays the given role. More...

Protected Member Functions
int	next (Pipeline_event event, Continuation continuation)
	Pass the event to the next handler in line. More...

int	next (Pipeline_action *action)
	Pass the action to the next handler in line. More...

Private Attributes
Event_handler *	next_in_pipeline

Detailed Description

Interface for the application of events, them being packets or log events.

Instances of this class can be composed among them to form execution pipelines.

Handlers can also have roles that define their type of activity and can be used to identify them in a pipeline. Roles are defined by the user of this class according to his context.

Constructor & Destructor Documentation

◆ Event_handler()

Event_handler::Event_handler ( )

inline

◆ ~Event_handler()

virtual Event_handler::~Event_handler ( )

virtualdefault

Member Function Documentation

◆ append()

void Event_handler::append ( Event_handler * last_handler )

inline

Append an handler to be the last in line for execution.

Parameters

[in] last_handler the last handler in line

◆ append_handler()

static void Event_handler::append_handler	(	Event_handler **	pipeline,
		Event_handler *	event_handler
	)

inlinestatic

Append an handler to a given pipeline.

Note: if the pipeline is null, the given handler will take its place

Parameters

[in,out]	pipeline	the pipeline to append the handler
[in]	event_handler	the event handler to append

◆ get_handler_by_role()

static void Event_handler::get_handler_by_role	(	Event_handler *	pipeline,
		int	role,
		Event_handler **	event_handler
	)

inlinestatic

Returns an handler that plays the given role.

Note: if the pipeline is null, or the handler is not found, the retrieved handler will be null.

Parameters

[in]	pipeline	the handler pipeline
[in]	role	the role to retrieve
[out]	event_handler	the retrieved event handler

◆ get_role()

virtual int Event_handler::get_role ( )

pure virtual

This method returns the handler role.

Handlers can have different roles according to the tasks they represent. Is based on this role that certain components can extract and interact with pipeline handlers. This means that if a role is given to a singleton handler, no one else can have that role.

Returns: the handler role

Implemented in Applier_handler, Certification_handler, and Event_cataloger.

◆ handle_action()

virtual int Event_handler::handle_action ( Pipeline_action * action )

pure virtual

Handling of an action as defined in the handler implementation.

As the handler can be included in a pipeline, somewhere in the method, the handler.next(action) method shall be invoked to allow the passing of the action to the next handler.

Note: Actions should not be treated asynchronously and as so, Continuations are not used here. Errors are returned directly or passed by in the action if it includes support for such

Parameters

[in] action the pipeline event to be handled

Implemented in Applier_handler, Certification_handler, and Event_cataloger.

◆ handle_event()

virtual int Event_handler::handle_event	(	Pipeline_event *	event,
		Continuation *	continuation
	)

pure virtual

Handling of an event as defined in the handler implementation.

As the handler can be included in a pipeline, somewhere in the method, the handler.next(event,continuation) method shall be invoked to allow the passing of the event to the next handler.

Also, if an error occurs, the continuation object shall be used to propagate such error. This class can also be used to know/report when the transaction to whom the event belongs was discarded.

Parameters

[in]	event	the pipeline event to be handled
[in,out]	continuation	termination notification object.

Implemented in Applier_handler, Certification_handler, and Event_cataloger.

◆ initialize()

virtual int Event_handler::initialize ( )

pure virtual

Initialization as defined in the handler implementation.

Note: It's up to the developer to decide its own initialization strategy, but the suggested approach is to initialize basic structures here and then depend on Action packets to configure and start existing handler routines.

Implemented in Applier_handler, Certification_handler, and Event_cataloger.

◆ is_unique()

virtual bool Event_handler::is_unique ( )

pure virtual

This method identifies the handler as being unique.

An handler that is defined as unique is an handler that cannot be used more than once in a pipeline. Such tasks as certification and event application can only be done once. Unique handlers are also the only that, by being one of a kind, can be extracted during the pipeline life allowing dynamic changes to them.

Returns: if the handler is the a unique handler

Return values

true	is a unique handler
false	is a repeatable handler

Implemented in Applier_handler, Certification_handler, and Event_cataloger.

◆ next() [1/2]

int Event_handler::next ( Pipeline_action * action )

inlineprotected

Pass the action to the next handler in line.

If none exists, this method will return

Parameters

[in] action the pipeline action to be handled

◆ next() [2/2]

int Event_handler::next	(	Pipeline_event *	event,
		Continuation *	continuation
	)

inlineprotected

Pass the event to the next handler in line.

If none exists, this method will signal the continuation method and exit.

Parameters

[in]	event	the pipeline event to be handled
[in,out]	continuation	termination notification object.

◆ plug_next_handler()

void Event_handler::plug_next_handler ( Event_handler * next_handler )

inline

Plug an handler to be the next in line for execution.

Parameters

[in] next_handler the next handler in line

◆ terminate()

virtual int Event_handler::terminate ( )

pure virtual

Terminate the execution as defined in the handler implementation.

Implemented in Applier_handler, Certification_handler, and Event_cataloger.

◆ terminate_pipeline()

int Event_handler::terminate_pipeline ( )

inline

Shutdown and delete all handlers in the pipeline.

Returns: the operation status

Return values

0	OK
!=0	Error

Member Data Documentation

◆ next_in_pipeline

Event_handler* Event_handler::next_in_pipeline

private

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

plugin/group_replication/include/pipeline_interfaces.h

Public Member Functions

Static Public Member Functions

Protected Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Event_handler()

◆ ~Event_handler()

Member Function Documentation

◆ append()

◆ append_handler()

◆ get_handler_by_role()

◆ get_role()

◆ handle_action()

◆ handle_event()

◆ initialize()

◆ is_unique()

◆ next() [1/2]

◆ next() [2/2]

◆ plug_next_handler()

◆ terminate()

◆ terminate_pipeline()

Member Data Documentation

◆ next_in_pipeline