ImageRegionObserverStorage Class Reference

#include <imageregionobserver_helpers.h>

Detailed Description

This class is a convenience wrapper to manage the lifetime of and access to long-living observers. It is only recommended to be used if smarter observer lifetime management is not feasible. It can be easily placed into or along-side image data owning classes. Observers are lazily registered on first fetch to avoid overhead if they are not used for a particular instance.

Classes
struct	StoredObserver

Public Types
using	AddObserverFunc = Delegate< Result< void >(const Id &observerId, const ImageRegionObserverRef &observer)>
using	InitializeObserversFunc = Delegate< Result< void >(const AddObserverFunc &addObserver)>

Public Member Functions
template<typename T_ObserverRef >
Result< T_ObserverRef >	GetObserver (const Id &observerId) const
Result< void >	Initialize (const InitializeObserversFunc &initializeObservers, Bool lazyRegistration)
const ImageRegionObservableHandlerRef &	GetObservableHandler () const
Bool	IsInitialized () const

Private Attributes
Bool	_isInitialized
LazyInitThreaded	_lazyRegistration
HashMap< Id, StoredObserver >	_observers
ImageRegionObservableHandlerRef	_observableHandler

Member Typedef Documentation

AddObserverFunc

using AddObserverFunc = Delegate<Result<void>(const Id & observerId, const ImageRegionObserverRef& observer)>

Gives access to adding an observer under a unique id.

Parameters

[in]	observerId	The identifier of the observer. This identifier must be unique.
[in]	observer	The observer to add.

Returns

OK on success.

InitializeObserversFunc

using InitializeObserversFunc = Delegate<Result<void>(const AddObserverFunc& addObserver)>

Gives access to the addition of an observer collection.

Parameters

[in]

addObserver

The add function for an observer.

Returns

OK on success.

Member Function Documentation

GetObserver()

Result<T_ObserverRef> GetObserver

(

const Id &

observerId

)

const

Returns an observer that has added under a particular id. The first call to the method will trigger the lazy registration of all added observers.

Returns

A valid observer reference, or error.

Initialize()

Result<void> Initialize	(	const InitializeObserversFunc &	initializeObservers,
		Bool	lazyRegistration
	)

Initializes the observable and creates a collection of long-living observers.

Parameters

[in]	initializeObservers	The function that adds the observers.
[in]	lazyRegistration	Determines whether the added observers should be lazily registered, or immediately.

Returns

OK on success.

GetObservableHandler()

const ImageRegionObservableHandlerRef& GetObservableHandler

(

)

const

Returns the handler to the observable, giving access to the registrar of observers and notification dispatch.

Returns

The observable.

IsInitialized()

Bool IsInitialized

(

)

const

Returns true if the observer storage is initialized.

Returns

True if initialized, false otherwise.

Member Data Documentation

_isInitialized

Bool _isInitialized

private

_lazyRegistration

LazyInitThreaded _lazyRegistration

mutableprivate

the initialization state.

_observers

HashMap<Id, StoredObserver> _observers

mutableprivate

the lazy execute-once registration function.

_observableHandler

ImageRegionObservableHandlerRef _observableHandler

private

the collection of managed observers.