active::event::Subscriber Class Reference

#include <Subscriber.h>

Inheritance diagram for active::event::Subscriber:

Collaboration diagram for active::event::Subscriber:

Public Types
enum class	Action { issue = 0 , suspend , renew , discontinue }
	The action awaited by the subscriber. More...
using	Unique = std::unique_ptr<Subscriber>
	Unique pointer.
using	Shared = std::shared_ptr<Subscriber>
	Shared pointer.
using	Weak = std::weak_ptr<Subscriber>
	Weak pointer.
using	Subscription = std::set<NameID>
	An event subscription list.
Public Types inherited from active::utility::NameID
using	Option = std::optional<NameID>
	Optional.

Public Member Functions
	Subscriber (int32_t priority=0)
	Subscriber (const utility::NameID &identity, int32_t priority=0)
virtual	~Subscriber ()=default
bool	operator== (const Subscriber &ref) const
bool	operator!= (const Subscriber &ref) const
virtual bool	getPriority () const
virtual Action	action () const
virtual Subscription	subscription () const =0
virtual bool	receive (const Event &event)=0
Public Member Functions inherited from active::event::Participant
	Participant (const utility::NameID &identity=utility::NameID{})
virtual	~Participant ()=default
bool	operator== (const Participant &ref) const
bool	operator!= (const Participant &ref) const
Public Member Functions inherited from active::utility::NameID
	NameID ()
	NameID (const String &str, const Guid &guid=Guid{})
	NameID (const char *str, const Guid &guid=Guid{})
	NameID (const Guid &guid, const String &str=String{})
bool	operator== (const NameID &ref) const
bool	operator!= (const NameID &ref) const
bool	operator< (const NameID &ref) const
	operator bool () const
void	clear ()

Protected Member Functions
void	setAction (Action action)
Protected Member Functions inherited from active::event::Participant
virtual bool	audit ()
virtual bool	attach ()
virtual bool	start ()
virtual void	stop ()

Friends
class	Publisher

Additional Inherited Members
Public Attributes inherited from active::utility::NameID
String	name
Guid	id

Detailed Description

A class representing an event subscriber

A Subscriber registers an interest with a Publisher for one or more Events. Incoming Events will be issued to Subscribers with a registered interest in order of priority (defined by the Subscriber). Any Subscriber can signal that the Event has been closed, at which point distribution of the event to other Subscribers will cease (e.g. a speific tool has completed a requested task that can only be solved once).

Subscribers are asked to fullfil several tasks:

• Audit their environment to ensure normal function
• Attach any components relevant to the app, e.g. UI additions
• Initialise, e.g. allocate resources
• Subscribe to at least one event
• Shutdown

Note that many subscribers don't need to do anything to fullfil these requirements, e.g. a subscriber with no dependencies has nothing to audit. Generally an 'attach' function is only needed where a subscriber has to notity some other system of its presence in order to receive events, e.g. a tool acting on the selection of a menu in the UI might need to register the menu resources with the UI manager.

Subscribers should wait for the publisher to instigate tasks like attach, initialise or shutdown. This will allow a manager acting as a Publisher to coordinate the actions of all its subscribers (which may be critical in some contexts).

Member Enumeration Documentation

Action

enum class active::event::Subscriber::Action

strong

The action awaited by the subscriber.

Enumerator
issue	Issue events.
suspend	Suspend operation.
renew	The subscriber has to be discontinued and restarted (audit, attach etc)
discontinue	The subscription is discontinued.

Constructor & Destructor Documentation

Subscriber() [1/2]

active::event::Subscriber::Subscriber ( int32_t priority = 0 )

inline

Default constructor

Parameters

priority

The subscriber priority (determines the order in which subscribers receive events)

Subscriber() [2/2]

active::event::Subscriber::Subscriber ( const utility::NameID & identity, int32_t priority = 0 )

inline

Constructor

Parameters

identity	Name/ID for the subscriber
priority	The subscriber priority (determines the order in which subscribers receive events)

~Subscriber()

virtual active::event::Subscriber::~Subscriber ( )

virtualdefault

Destructor

Member Function Documentation

action()

virtual Action active::event::Subscriber::action ( ) const

inlinevirtual

Get the subscriber action

Returns

The subscriber action

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getPriority()

virtual bool active::event::Subscriber::getPriority ( ) const

inlinevirtual

Get the subscriber priority

Returns

The subscriber priority

operator!=()

bool active::event::Subscriber::operator!= ( const Subscriber & ref ) const

inline

Inequality operator

Parameters

ref	The object to compare with this

Returns

True if ref is not equal to this

operator==()

bool active::event::Subscriber::operator== ( const Subscriber & ref ) const

inline

Equality operator

Parameters

ref	The object to compare with this

Returns

True if ref is equal to this

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receive()

virtual bool active::event::Subscriber::receive ( const Event & event )

pure virtual

Receive a subscribed event

Parameters

event

The incoming event

Returns

True if the event should be closed

setAction()

void active::event::Subscriber::setAction ( Action action )

inlineprotected

Get the subscriber action

Parameters

action

The subscriber action

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subscription()

virtual Subscription active::event::Subscriber::subscription ( ) const

pure virtual

Get the event subscription list

Returns

The subscription list (an empty list will put the subscriber into a suspended state)

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

• /Users/rwessel/Documents/Development/ActiveLib/Active/Event/Subscriber.h