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CContextEngine Class Reference

class CContextEngine : public CBase

An engine to collect context metadata with available context plugins. CContextEngineAO is used to do the actual work. This class is implemented as a Singleton.

Inherits from

CContextEngine
- CBase

Public Member Functions
	~CContextEngine()
IMPORT_C void	ContextSnapshot(MContextSnapshotObserver &, CHarvesterData &)
IMPORT_C void	ContextSnapshot(MContextSnapshotObserver &, RPointerArray< CHarvesterData > &)
void	ContextSnapshotStatus(CHarvesterData *)
IMPORT_C void	Destroy()
IMPORT_C CContextEngine *	GetInstanceL(MContextInitializationObserver *)
IMPORT_C TInt	PluginCount()
IMPORT_C void	ReleaseInstance()
IMPORT_C void	SetMdeSession(CMdESession *)

Private Member Functions
	CContextEngine()
void	ConstructL(MContextInitializationObserver *)
void	QueueSnapshotItem(CContextSnapshotItem *)

Inherited Functions
	CBase::CBase()
	CBase::Delete(CBase *)
	CBase::Extension_(TUint,TAny &,TAny )
	CBase::operator new(TUint)
	CBase::operator new(TUint,TAny *)
	CBase::operator new(TUint,TLeave)
	CBase::operator new(TUint,TLeave,TUint)
	CBase::operator new(TUint,TUint)
	CBase::~CBase()

Private Attributes
TInt	iArrayCount
CContextEngineAO *	iContextEngineAO
TInt	iProcessedArrayCount
RPointerArray< CContextSnapshotItem >	iSnapshotQueue

Constructor & Destructor Documentation

CContextEngine()

CContextEngine

(

)

[private]

C++ constructor - not exported; implicitly called from GetInstance()

~CContextEngine()

~CContextEngine

(

)

[virtual]

Destroys the implementation. This is virtual method and this class is not intended for derivation, so not exported.

Member Functions Documentation

ConstructL(MContextInitializationObserver *)

void

ConstructL

(

MContextInitializationObserver *

aObserver

)

[private]

2nd phase construction, called by GetInstance()

Parameters

MContextInitializationObserver * aObserver

object/callback to notify when initialization is ready.

ContextSnapshot(MContextSnapshotObserver &, CHarvesterData &)

IMPORT_C void	ContextSnapshot	(	MContextSnapshotObserver &	aObserver,
			CHarvesterData &	aHD
		)

Context snapshot. This takes the snapshot using plug-ins.

Parameters

MContextSnapshotObserver & aObserver	an interface class for callback.
CHarvesterData & aHD

ContextSnapshot(MContextSnapshotObserver &, RPointerArray< CHarvesterData > &)

IMPORT_C void	ContextSnapshot	(	MContextSnapshotObserver &	aObserver,
			RPointerArray< CHarvesterData > &	aMetadataObjectArray
		)

Context snapshot. This takes the snapshot using plug-ins.

Parameters

MContextSnapshotObserver & aObserver	an interface class for callback.
RPointerArray< CHarvesterData > & aMetadataObjectArray	An array of MdE objects the snapshot is taken to.

ContextSnapshotStatus(CHarvesterData *)

void

ContextSnapshotStatus

(

CHarvesterData *

aHD

)

From MContextEngineObserver. Method is called by CContextEngineAO when a context snapshot is finished or an error has occured.

Parameters

CHarvesterData * aHD

Destroy()

IMPORT_C void

Destroy

(

)

Ignores the reference count and destroys this singleton. THINK BEFORE USING! Should be used only instead of reference counting if clients are not calling ReleaseInstance() (which they should).

GetInstanceL(MContextInitializationObserver *)

IMPORT_C CContextEngine *

GetInstanceL

(

MContextInitializationObserver *

aObserver = NULL

)

[static]

Gets an instance to CContextEngine singleton. A new object is created if needed. If an observer object to notify is given, context plugins are initialized asyncronously and observer is notified when ready.

Parameters

MContextInitializationObserver * aObserver = NULL

an interface class for callback or NULL

PluginCount()

IMPORT_C TInt

PluginCount

(

)

Method used to clarify amount of plug-ins.

QueueSnapshotItem(CContextSnapshotItem *)

void

QueueSnapshotItem

(

CContextSnapshotItem *

aItem

)

[private]

Add a new observer and metadata items to a queue. These observers need to be informed when a snapshot is ready and items need a context snapshot.

Parameters

CContextSnapshotItem * aItem

An item to add.

ReleaseInstance()

IMPORT_C void

ReleaseInstance

(

)

Release an instance of this singleton.

SetMdeSession(CMdESession *)

IMPORT_C void

SetMdeSession

(

CMdESession *

aSession

)

Set a pointer to MdESession. The pointer is given forward to context plugins. Session must be set in order to successfully harvest context data.

Parameters

CMdESession * aSession

Session pointer to set.

Member Data Documentation

TInt iArrayCount

TInt

iArrayCount

[private]

In case array of objects for snapshot were passed, variable to store the amount of items to be processed.

CContextEngineAO * iContextEngineAO

CContextEngineAO *

iContextEngineAO

[private]

This active object is used to handle queued snapshot requests.

TInt iProcessedArrayCount

TInt

iProcessedArrayCount

[private]

In case array of objects for snapshot were passed, variable to store the amount of items that have been processed.

RPointerArray< CContextSnapshotItem > iSnapshotQueue

RPointerArray< CContextSnapshotItem >

iSnapshotQueue

[private]

Array of observers and related metadata objects that need a context snapshot. Related observer is informed about snapshot completion.