Object reference supporting deferred reading from StoreGate. More...

#include <DataLink.h>

Inheritance diagram for DataLink< STORABLE >:

Collaboration diagram for DataLink< STORABLE >:

Public Types
typedef STORABLE	value_type
	Names for the referenced type and derivatives. More...

typedef STORABLE *	pointer

typedef const STORABLE *	const_pointer

typedef STORABLE &	reference

typedef const STORABLE &	const_reference

typedef DataLinkBase::ID_type	ID_type
	A string SG key. More...

typedef DataLinkBase::sgkey_t	sgkey_t
	A hashed SG key. More...

typedef DataLink< STORABLE >	self
	Convenience declaration of this structure's type. More...

typedef SG::DataProxyHolder::pointer_t	pointer_t

typedef SG::DataProxyHolder::const_pointer_t	const_pointer_t

typedef SG::DataProxyHolder::castfn_t	castfn_t
	Function casting from a `SG::DataProxy` to a pointer. More...

Type definitions taken from the StoreGate-based implementation
typedef std::string	ID_type
	Type of the "regular" identifiers in the event. More...

typedef uint32_t	sgkey_t
	Integer identifier for the object in the event. More...

typedef STORABLE	value_type
	Type of the object being handled. More...

typedef STORABLE *	__attribute__((deprecated)) pointer
	Pointer type for the object being handled. More...

typedef const STORABLE *	const_pointer
	Constant pointer type for the object being handled. More...

typedef STORABLE &	__attribute__((deprecated)) reference
	Reference type for the object being handled. More...

typedef const STORABLE &	const_reference
	Constant reference type for the object being handled. More...

Public Member Functions
xAOD::TVirtualEvent *	source () const
	Get the data source for the reference. More...

bool	toPersistent ()
	Prepare the object to be written out. More...

bool	isDefault () const
	Test to see if we're in the default state. More...

bool	isDefault () const
	Test if the link is in the default state. More...

void	clear ()
	Clear the link (make it null). More...

void	clear ()
	Clear the link (make it null) More...

SG::DataProxy *	proxy (bool nothrow=false) const
	Return the `DataProxy` for this link. More...

bool	toTransient (const ID_type &dataID, CLID link_clid, IProxyDict *sg=0)
	Finish initialization like the link as just been read from root, but with a specified key. More...

bool	toTransient (const ID_type &dataID, CLID link_clid, const EventContext &ctx)
	Finish initialization like the link as just been read from root, but with a specified key. More...

bool	toPersistentNoRemap ()
	Prepare this link for writing. More...

bool	operator== (const DataLinkBase &other) const
	Compare for equality. More...

bool	operator!= (const DataLinkBase &other) const
	Compare for inequality. More...

uint32_t	persKey () const
	Get the key/identifier of the referenced container. More...

void	setPersKey (uint32_t key)
	Set the key/identifier of the referenced container. More...

Constructors.
	DataLink ()
	Default constructor — gives the equivalent of a NULL pointer. More...

	DataLink (const_reference data, IProxyDict *sg=0)
	Constructor — link to a STORABLE using a transient ref to it. More...

	DataLink (const_reference data, const EventContext &ctx)
	Constructor — link to a STORABLE using a transient ref to it. More...

	DataLink (const_pointer pdata, IProxyDict *sg=0)
	Constructor — link to a STORABLE using a transient pointer to it. More...

	DataLink (const_pointer pdata, const EventContext &ctx)
	Constructor — link to a STORABLE using a transient pointer to it. More...

	DataLink (const ID_type &dataID, IProxyDict *sg=0)
	Constructor — link to a STORABLE using a string ID. More...

	DataLink (const ID_type &dataID, const EventContext &ctx)
	Constructor — link to a STORABLE using a string ID. More...

	DataLink (sgkey_t key, IProxyDict *sg=0)
	Constructor — link to a STORABLE using a hashed ID. More...

	DataLink (sgkey_t key, const EventContext &ctx)
	Constructor — link to a STORABLE using a hashed ID. More...

	DataLink (sgkey_t key, const SG::DataProxyHolder &holder)
	Constructor from a hashed key and a proxy holder object. More...

Setters.
void	toStorableObject (const_reference data, IProxyDict *sg=0)
	Set the link to an object given by a reference. More...

void	toStorableObject (const_reference data, const EventContext &ctx)
	Set the link to an object given by a reference. More...

void	toIdentifiedObject (const ID_type &dataID, IProxyDict *sg=0)
	Set the link to an object given by a string key. More...

void	toIdentifiedObject (const ID_type &dataID, const EventContext &ctx)
	Set the link to an object given by a string key. More...

void	toIdentifiedObject (sgkey_t key, IProxyDict *sg=0)
	Set the link to an object given by a hashed key. More...

void	toIdentifiedObject (sgkey_t key, const EventContext &ctx)
	Set the link to an object given by a hashed key. More...

void	toDefaultObject (IProxyDict *sg=0)
	Set the link to the default object of this type. More...

void	toDefaultObject (const EventContext &ctx)
	Set the link to the default object of this type. More...

bool	toTransient (IProxyDict *sg=0)
	Finish initialization after link has been read. More...

bool	toTransient (const EventContext &ctx)
	Finish initialization after link has been read. More...

bool	toTransient (const ID_type &dataID, IProxyDict *sg=0)
	Finish initialization like the link as just been read from root, but with a specified key. More...

bool	toTransient (const ID_type &dataID, const EventContext &ctx)
	Finish initialization like the link as just been read from root, but with a specified key. More...

Constructors
	DataLink ()
	Default constructor, creating a null pointer basically. More...

	DataLink (xAOD::TVirtualEvent *event)
	Constructor taking an alternative TVirtualEvent object to use. More...

	DataLink (const_reference data, xAOD::TVirtualEvent *event=0)
	Constructor receiving a reference to the target object. More...

	DataLink (const_pointer data, xAOD::TVirtualEvent *event=0)
	Constructor receiving a pointer to the target object. More...

	DataLink (const ID_type &id, xAOD::TVirtualEvent *event=0)
	Constructor receiving a user-readable ID for the target object. More...

	DataLink (sgkey_t key, xAOD::TVirtualEvent *event=0)
	Constructor receiving a hashed ID for the target object. More...

template<typename T >
	DataLink (const DataLink< T > &parent)
	Copy constructor. More...

Setter functions
void	toStorableObject (const_reference data)
	Set the link to a data object that's already in the event. More...

void	toDefaultObject ()
	Set the link to the default object of this type in the event. More...

void	toIdentifiedObject (const ID_type &id)
	Set the link using a user readable ID for the target object. More...

void	toIdentifiedObject (sgkey_t key)
	Set the link using a hashed ID for the target object. More...

Accessor functions
const_reference	operator* () const
	Get a reference to the target object. May throw an exception. More...

const_pointer	operator-> () const
	Get a pointer to the target object. More...

	operator const_pointer () const
	Automatic conversion operator. More...

const_pointer	cptr () const
	Get a constant pointer to the referenced object. More...

bool	isValid () const
	Check if the object can be found. More...

	operator bool () const
	Convenience validity check operator. More...

bool	operator! () const
	Another convenience validity checker. More...

const ID_type &	dataID () const
	Get the key that we reference, as a string. More...

sgkey_t	key () const
	Get the key that we reference, as a hash. More...

Static Public Member Functions
static const CLID &	classID ()
	Return the CLID for the class that we reference. More...

Public Attributes
ROOT_SELECTION_NS::MemberAttributes< kTransient >	m_object
	Declare m_object as transient. More...

ROOT_SELECTION_NS::MemberAttributes< kTransient >	m_event
	Declare m_event as transient. More...

Protected Member Functions
void	toStorableObject (const_pointer_t obj, CLID clid_in, IProxyDict *sg)
	Set the link to an object given by a pointer. More...

void	toIdentifiedObject (const ID_type &dataID, CLID clid, IProxyDict *sg)
	Set the link to an object given by a string key. More...

void	toIdentifiedObject (sgkey_t key, CLID clid, IProxyDict *sg)
	Set the link to an object given by a hashed key. More...

void *	storableBase (castfn_t *castfn, const CLID &clid, bool isConst) const
	Return a pointer to the currently-referenced object. More...

void	throwInvalidLink () const
	Throw a `ExcInvalidLink` exception for this link. More...

Protected Attributes
uint32_t	m_persKey
	Key/identifier of the referenced object. More...

bool	m_isDirectIO
	A transient variable signalling when direct I/O is happening. More...

Private Types
typedef ROOT_SELECTION_NS::DataLink< STORABLE >::self	DictSel
	Needed to take the Reflex/Cling specifications into account. More...

Private Member Functions
virtual bool	toTransient ()
	Reset the object's internal cache. More...

void	findIdentifier ()
	Find the identifier of the object being pointed to. More...

Private Attributes
const_pointer	m_object
	Cached pointer to the object. More...

xAOD::TVirtualEvent *	m_event
	Pointer to the event object. More...

sgkey_t	m_persKey
	The hashed key for this link. More...

SG::DataProxyHolder	m_proxy
	SG proxy for this link. More...

Accessors.
const_pointer	getDataPtr () const
	Return a pointer to the currently-referenced object. More...

pointer	getDataNonConstPtr ()
	Return a pointer to the currently-referenced object. More...

const_reference	operator* () const
	Dereference the link. More...

const_pointer	operator-> () const
	Dereference the link. More...

	operator const_pointer () const
	Dereference the link. More...

const_pointer	cptr () const
	Dereference the link. More...

bool	isValid () const
	Test to see if the link is dereferencable. More...

bool	operator! () const
	True if the link is not dereferencable. More...

const void *	storable () const
	Return a (void) pointer to the currently-referenced object. More...

void *	storableNonConst ()
	Return a (void) pointer to the currently-referenced object. More...

Detailed Description

template<class STORABLE>
class DataLink< STORABLE >

Object reference supporting deferred reading from StoreGate.

This is a kind of smart pointer that can reference objects in StoreGate by key. This allows deferred-reading semantics, and also allows references to objects that may be in a different physical data file (‘back-navigation’).

For example:

DataLink<MyClass> link ("mykey");
...
// Look up the object `mykey' of class MyClass in StoreGate.
const MyClass* obj = *link;

You can also initialize a link directly with a pointer:

MyClass* obj = ...;

DataLink<MyClass> link (obj);

However, if the object has not been recorded in the event store, the possible operations on the link will be limited. (In particular, such a link cannot be made persistent.)

A DataLink can exist in one of three states:

A null reference.
Referring to an object in StoreGate. In this case, the link refers to the DataProxy for the referred-to object.
Referring to an object directly by pointer. When you initialize a link from a pointer, the link will try to find the corresponding proxy. However, if one doesn't exist, the link will remember the pointer directly. If a subsequent operation is attempted that requires the proxy (such as toPersistent or getting the key) and the object still isn't in StoreGate, SG::ExcPointerNotInSG will be thrown.

Internally, a link stores a hashed version of the SG key + CLID; this is the part that's persistent. (In the case of a link referencing an object not in SG, this field is 0.) There is also a transient pointer to either the proxy or the object itself (if the object is not in SG). This latter pointer is factored out as DataProxyHolder in order to share implementation with ElementLink. Further, everything which does not depend on the STORABLE template parameter, including all the object state, is factored out into the non-templated base class DataLinkBase.

If the link is being saved directly with ROOT, then toPersistent should be called prior to writing. This will ensure that the hashed StoreGate key is set correctly (and will raise an exception if the link is referencing an object not in SG). This will also handle any remapping of the link. When a link is read directly from ROOT, toTransient should be called to set the proxy pointer. This would normally be done via a ROOT read rule.

A link references objects in a particular event store. When a link is constructed, a global default store is used (see SGTools/CurrentEventStore.h). If a link is subsequently modified, it stays associated with the same store, unless the link was null or was referencing an object directly by pointer, in which case the global default is again used. Alternatively, the event store may be passed explicitly using the optional sg parameter.

Definition at line 93 of file AthLinks/DataLink.h.

Member Typedef Documentation

◆ attribute [1/2]

template<class STORABLE >

typedef STORABLE* DataLink< STORABLE >::__attribute__((deprecated)) pointer

Pointer type for the object being handled.

Definition at line 53 of file A/AthLinks/DataLink.h.

◆ attribute [2/2]

template<class STORABLE >

typedef STORABLE& DataLink< STORABLE >::__attribute__((deprecated)) reference

Reference type for the object being handled.

Definition at line 57 of file A/AthLinks/DataLink.h.

◆ castfn_t

typedef SG::DataProxyHolder::castfn_t DataLinkBase::castfn_t

inherited

Function casting from a SG::DataProxy to a pointer.

Definition at line 49 of file AthLinks/DataLinkBase.h.

◆ const_pointer [1/2]

template<class STORABLE >

typedef const STORABLE* DataLink< STORABLE >::const_pointer

Constant pointer type for the object being handled.

Definition at line 55 of file A/AthLinks/DataLink.h.

◆ const_pointer [2/2]

template<class STORABLE >

typedef const STORABLE* DataLink< STORABLE >::const_pointer

Definition at line 100 of file AthLinks/DataLink.h.

◆ const_pointer_t

typedef SG::DataProxyHolder::const_pointer_t DataLinkBase::const_pointer_t

inherited

Definition at line 46 of file AthLinks/DataLinkBase.h.

◆ const_reference [1/2]

template<class STORABLE >

typedef const STORABLE& DataLink< STORABLE >::const_reference

Constant reference type for the object being handled.

Definition at line 59 of file A/AthLinks/DataLink.h.

◆ const_reference [2/2]

template<class STORABLE >

typedef const STORABLE& DataLink< STORABLE >::const_reference

Definition at line 102 of file AthLinks/DataLink.h.

◆ DictSel

template<class STORABLE >

typedef ROOT_SELECTION_NS::DataLink< STORABLE >::self DataLink< STORABLE >::DictSel

private

Needed to take the Reflex/Cling specifications into account.

Definition at line 153 of file A/AthLinks/DataLink.h.

◆ ID_type [1/2]

template<class STORABLE >

typedef std::string DataLink< STORABLE >::ID_type

Type of the "regular" identifiers in the event.

Definition at line 46 of file A/AthLinks/DataLink.h.

◆ ID_type [2/2]

template<class STORABLE >

typedef DataLinkBase::ID_type DataLink< STORABLE >::ID_type

A string SG key.

Definition at line 105 of file AthLinks/DataLink.h.

◆ pointer

template<class STORABLE >

typedef STORABLE* DataLink< STORABLE >::pointer

Definition at line 99 of file AthLinks/DataLink.h.

◆ pointer_t

typedef SG::DataProxyHolder::pointer_t DataLinkBase::pointer_t

inherited

Definition at line 45 of file AthLinks/DataLinkBase.h.

◆ reference

template<class STORABLE >

typedef STORABLE& DataLink< STORABLE >::reference

Definition at line 101 of file AthLinks/DataLink.h.

◆ self

template<class STORABLE >

typedef DataLink< STORABLE > DataLink< STORABLE >::self

Convenience declaration of this structure's type.

Definition at line 168 of file A/AthLinks/DataLink.h.

◆ sgkey_t [1/2]

template<class STORABLE >

typedef uint32_t DataLink< STORABLE >::sgkey_t

Integer identifier for the object in the event.

Definition at line 48 of file A/AthLinks/DataLink.h.

◆ sgkey_t [2/2]

template<class STORABLE >

typedef DataLinkBase::sgkey_t DataLink< STORABLE >::sgkey_t

A hashed SG key.

Definition at line 108 of file AthLinks/DataLink.h.

◆ value_type [1/2]

template<class STORABLE >

typedef STORABLE DataLink< STORABLE >::value_type

Type of the object being handled.

Definition at line 51 of file A/AthLinks/DataLink.h.

◆ value_type [2/2]

template<class STORABLE >

typedef STORABLE DataLink< STORABLE >::value_type

Names for the referenced type and derivatives.

Definition at line 98 of file AthLinks/DataLink.h.

Constructor & Destructor Documentation

◆ DataLink() [1/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink ( )

Default constructor — gives the equivalent of a NULL pointer.

◆ DataLink() [2/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const_reference	data,
		IProxyDict *	sg = `0`
	)

Constructor — link to a STORABLE using a transient ref to it.

Parameters

data	The object to which to link.
sg	Associated store; if 0, use the global default.

◆ DataLink() [3/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const_reference	data,
		const EventContext &	ctx
	)

Constructor — link to a STORABLE using a transient ref to it.

Parameters

data	The object to which to link.
ctx	Event context for this link.

◆ DataLink() [4/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const_pointer	pdata,
		IProxyDict *	sg = `0`
	)

Constructor — link to a STORABLE using a transient pointer to it.

Parameters

data	The object to which to link.
sg	Associated store; if 0, use the global default.

◆ DataLink() [5/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const_pointer	pdata,
		const EventContext &	ctx
	)

Constructor — link to a STORABLE using a transient pointer to it.

Parameters

data	The object to which to link.
ctx	Event context for this link.

◆ DataLink() [6/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const ID_type &	dataID,
		IProxyDict *	sg = `0`
	)

Constructor — link to a STORABLE using a string ID.

Parameters

dataID	Key of the object.
sg	Associated store; if 0, use the global default.

◆ DataLink() [7/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const ID_type &	dataID,
		const EventContext &	ctx
	)

Constructor — link to a STORABLE using a string ID.

Parameters

dataID	Key of the object.
ctx	Event context for this link.

◆ DataLink() [8/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	sgkey_t	key,
		IProxyDict *	sg = `0`
	)

Constructor — link to a STORABLE using a hashed ID.

Parameters

key	Hashed key of the object.
sg	Associated store; if 0, use the global default.

May throw ExcCLIDMismatch.

◆ DataLink() [9/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	sgkey_t	key,
		const EventContext &	ctx
	)

Constructor — link to a STORABLE using a hashed ID.

Parameters

key	Hashed key of the object.
ctx	Event context for this link.

May throw ExcCLIDMismatch.

◆ DataLink() [10/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	sgkey_t	key,
		const SG::DataProxyHolder &	holder
	)

Constructor from a hashed key and a proxy holder object.

Used internally for EL -> DL conversion.

Parameters

key	Hashed key of the object.
holder	Internal holder object for the proxy.

◆ DataLink() [11/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink ( )

Default constructor, creating a null pointer basically.

◆ DataLink() [12/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink ( xAOD::TVirtualEvent * event )

Constructor taking an alternative TVirtualEvent object to use.

◆ DataLink() [13/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const_reference	data,
		xAOD::TVirtualEvent *	event = `0`
	)

Constructor receiving a reference to the target object.

◆ DataLink() [14/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const_pointer	data,
		xAOD::TVirtualEvent *	event = `0`
	)

Constructor receiving a pointer to the target object.

◆ DataLink() [15/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	const ID_type &	id,
		xAOD::TVirtualEvent *	event = `0`
	)

Constructor receiving a user-readable ID for the target object.

◆ DataLink() [16/17]

template<class STORABLE >

DataLink< STORABLE >::DataLink	(	sgkey_t	key,
		xAOD::TVirtualEvent *	event = `0`
	)

Constructor receiving a hashed ID for the target object.

◆ DataLink() [17/17]

template<class STORABLE >

template<typename T >

DataLink< STORABLE >::DataLink ( const DataLink< T > & parent )

Copy constructor.

Member Function Documentation

◆ classID()

template<class STORABLE >

static const CLID& DataLink< STORABLE >::classID ( )

static

Return the CLID for the class that we reference.

◆ clear() [1/2]

void DataLinkBase::clear ( )

inherited

Clear the link (make it null)

◆ clear() [2/2]

void DataLinkBase::clear ( )

inherited

Clear the link (make it null).

Definition at line 36 of file DataLinkBase.cxx.

                          {
  
    m_persKey = 0;
    return;
 }

◆ cptr() [1/2]

template<class STORABLE >

const_pointer DataLink< STORABLE >::cptr ( ) const

Get a constant pointer to the referenced object.

◆ cptr() [2/2]

template<class STORABLE >

const_pointer DataLink< STORABLE >::cptr ( ) const

Dereference the link.

◆ dataID()

template<class STORABLE >

const ID_type& DataLink< STORABLE >::dataID ( ) const

Get the key that we reference, as a string.

◆ findIdentifier()

template<class STORABLE >

void DataLink< STORABLE >::findIdentifier ( )

private

Find the identifier of the object being pointed to.

◆ getDataNonConstPtr()

template<class STORABLE >

pointer DataLink< STORABLE >::getDataNonConstPtr ( )

Return a pointer to the currently-referenced object.

Returns: A pointer to an object of the type given by clid, or null on a failure (or if the reference is null).

◆ getDataPtr()

template<class STORABLE >

const_pointer DataLink< STORABLE >::getDataPtr ( ) const

Return a pointer to the currently-referenced object.

Returns: A pointer to an object of the type given by clid, or null on a failure (or if the reference is null).

◆ isDefault() [1/2]

bool DataLinkBase::isDefault ( ) const

inherited

Test if the link is in the default state.

◆ isDefault() [2/2]

bool DataLinkBase::isDefault ( ) const

inherited

Test to see if we're in the default state.

Definition at line 31 of file DataLinkBase.cxx.

                                    {
  
    return ( m_persKey == 0 );
 }

◆ isValid() [1/2]

template<class STORABLE >

bool DataLink< STORABLE >::isValid ( ) const

Check if the object can be found.

◆ isValid() [2/2]

template<class STORABLE >

bool DataLink< STORABLE >::isValid ( ) const

Test to see if the link is dereferencable.

◆ key()

template<class STORABLE >

sgkey_t DataLink< STORABLE >::key ( ) const

inline

Get the key that we reference, as a hash.

Definition at line 131 of file A/AthLinks/DataLink.h.

131 { return persKey(); }

◆ operator bool()

template<class STORABLE >

DataLink< STORABLE >::operator bool ( ) const

inline

Convenience validity check operator.

Definition at line 124 of file A/AthLinks/DataLink.h.

124 { return isValid(); }

◆ operator const_pointer() [1/2]

template<class STORABLE >

DataLink< STORABLE >::operator const_pointer ( ) const

inline

Automatic conversion operator.

Definition at line 115 of file A/AthLinks/DataLink.h.

115 { return cptr(); }

◆ operator const_pointer() [2/2]

template<class STORABLE >

DataLink< STORABLE >::operator const_pointer ( ) const

Dereference the link.

◆ operator!() [1/2]

template<class STORABLE >

bool DataLink< STORABLE >::operator! ( ) const

inline

Another convenience validity checker.

Definition at line 126 of file A/AthLinks/DataLink.h.

126 { return !isValid(); }

◆ operator!() [2/2]

template<class STORABLE >

bool DataLink< STORABLE >::operator! ( ) const

True if the link is not dereferencable.

◆ operator!=()

bool DataLinkBase::operator!= ( const DataLinkBase & other ) const

inherited

Compare for inequality.

◆ operator*() [1/2]

template<class STORABLE >

const_reference DataLink< STORABLE >::operator* ( ) const

Get a reference to the target object. May throw an exception.

◆ operator*() [2/2]

template<class STORABLE >

const_reference DataLink< STORABLE >::operator* ( ) const

Dereference the link.

◆ operator->() [1/2]

template<class STORABLE >

const_pointer DataLink< STORABLE >::operator-> ( ) const

inline

Get a pointer to the target object.

Definition at line 112 of file A/AthLinks/DataLink.h.

112 { return cptr(); }

◆ operator->() [2/2]

template<class STORABLE >

const_pointer DataLink< STORABLE >::operator-> ( ) const

Dereference the link.

◆ operator==()

bool DataLinkBase::operator== ( const DataLinkBase & other ) const

inherited

Compare for equality.

◆ persKey()

uint32_t DataLinkBase::persKey ( ) const

inherited

Get the key/identifier of the referenced container.

Definition at line 13 of file DataLinkBase.cxx.

                                      {
  
    return m_persKey;
 }

◆ proxy()

SG::DataProxy* DataLinkBase::proxy ( bool nothrow = false ) const

inherited

Return the DataProxy for this link.

Parameters

nothrow If true, return 0 on failure instead of throwing an exception.

If this is a null link, we return 0. If we're directly referencing an object that's not in StoreGate, either return 0 or throw ExcPointerNotInSG, depending on nothrow. Otherwise, return the proxy for the object we're referencing.

◆ setPersKey()

void DataLinkBase::setPersKey ( uint32_t key )

inherited

Set the key/identifier of the referenced container.

Definition at line 18 of file DataLinkBase.cxx.

                                             {
  
    // Check if we're actually changing anything:
    if( m_persKey == key ) return;
    // Store the new key:
    m_persKey = key;
  
    // Reset the internal cache:
    toTransient();
  
    return;
 }

◆ source()

template<class STORABLE >

xAOD::TVirtualEvent* DataLink< STORABLE >::source ( ) const

inline

Get the data source for the reference.

Definition at line 136 of file A/AthLinks/DataLink.h.

136 { return m_event; }

◆ storable()

template<class STORABLE >

const void* DataLink< STORABLE >::storable ( ) const

private

Return a (void) pointer to the currently-referenced object.

Returns: A pointer to an object of the type given by clid, or null on a failure (or if the reference is null).

◆ storableBase()

void* DataLinkBase::storableBase	(	castfn_t *	castfn,
		const CLID &	clid,
		bool	isConst
	)		const

protectedinherited

Return a pointer to the currently-referenced object.

Parameters

castfn	Function to do the cast from data proxy to object. If 0, use a dynamic cast.
clid	The CLID of the desired object. This is used to determine how the returned pointer is to be converted.
isConst	True if the returned object will be treated as const.

Returns: A pointer to an object of the type given by clid, or null on a failure (or if the reference is null).

◆ storableNonConst()

template<class STORABLE >

void* DataLink< STORABLE >::storableNonConst ( )

private

Return a (void) pointer to the currently-referenced object.

Returns: A pointer to an object of the type given by clid, or null on a failure (or if the reference is null).

◆ throwInvalidLink()

void DataLinkBase::throwInvalidLink ( ) const

protectedinherited

Throw a ExcInvalidLink exception for this link.

Parameters

sgkey The hashed key for this link.

This will fill in parameters for the exception message from the proxy.

◆ toDefaultObject() [1/3]

template<class STORABLE >

void DataLink< STORABLE >::toDefaultObject ( )

Set the link to the default object of this type in the event.

◆ toDefaultObject() [2/3]

template<class STORABLE >

void DataLink< STORABLE >::toDefaultObject ( const EventContext & ctx )

Set the link to the default object of this type.

Parameters

ctx	Event context for this link.

Note that this is not the same as clearing the link (use clear for that). This produces a link that will resolve to any object in SG of the given type, provided that there is only one of them. (An attempt to dereference an ambiguous default link will give an error.)

◆ toDefaultObject() [3/3]

template<class STORABLE >

void DataLink< STORABLE >::toDefaultObject ( IProxyDict * sg = 0 )

Set the link to the default object of this type.

Parameters

sg	Associated store.

If sg is 0, then we take the store from whatever the link's currently set to. If the link has no current store, then we take the global default.

Note that this is not the same as clearing the link (use clear for that). This produces a link that will resolve to any object in SG of the given type, provided that there is only one of them. (An attempt to dereference an ambiguous default link will give an error.)

◆ toIdentifiedObject() [1/8]

void DataLinkBase::toIdentifiedObject	(	const ID_type &	dataID,
		CLID	clid,
		IProxyDict *	sg
	)

protectedinherited

Set the link to an object given by a string key.

Parameters

dataID	Key of the object.
link_clid	CLID of the link being set.
sg	Associated store.

Returns: The SG key for this object.

If sg is 0, then we take the store from whatever the link's currently set to. If the link has no current store, then we take the global default.

◆ toIdentifiedObject() [2/8]

template<class STORABLE >

void DataLink< STORABLE >::toIdentifiedObject	(	const ID_type &	dataID,
		const EventContext &	ctx
	)

Set the link to an object given by a string key.

Parameters

dataID	Key of the object.
ctx	Event context for this link.

◆ toIdentifiedObject() [3/8]

template<class STORABLE >

void DataLink< STORABLE >::toIdentifiedObject	(	const ID_type &	dataID,
		IProxyDict *	sg = `0`
	)

Set the link to an object given by a string key.

Parameters

dataID	Key of the object.
sg	Associated store.

If sg is 0, then we take the store from whatever the link's currently set to. If the link has no current store, then we take the global default.

◆ toIdentifiedObject() [4/8]

template<class STORABLE >

void DataLink< STORABLE >::toIdentifiedObject ( const ID_type & id )

Set the link using a user readable ID for the target object.

◆ toIdentifiedObject() [5/8]

template<class STORABLE >

void DataLink< STORABLE >::toIdentifiedObject ( sgkey_t key )

Set the link using a hashed ID for the target object.

◆ toIdentifiedObject() [6/8]

void DataLinkBase::toIdentifiedObject	(	sgkey_t	key,
		CLID	clid,
		IProxyDict *	sg
	)

protectedinherited

Set the link to an object given by a hashed key.

Parameters

key	Hashed key of the object.
link_clid	CLID of the link being set.
sg	Associated store.

If sg is 0, then we take the store from whatever the link's currently set to. If the link has no current store, then we take the global default.

May throw ExcCLIDMismatch.

◆ toIdentifiedObject() [7/8]

template<class STORABLE >

void DataLink< STORABLE >::toIdentifiedObject	(	sgkey_t	key,
		const EventContext &	ctx
	)

Set the link to an object given by a hashed key.

Parameters

key	Hashed key of the object.
ctx	Event context for this link.

May throw ExcCLIDMismatch.

◆ toIdentifiedObject() [8/8]

template<class STORABLE >

void DataLink< STORABLE >::toIdentifiedObject	(	sgkey_t	key,
		IProxyDict *	sg = `0`
	)

Set the link to an object given by a hashed key.

Parameters

key	Hashed key of the object.
sg	Associated store.

If sg is 0, then we take the store from whatever the link's currently set to. If the link has no current store, then we take the global default.

May throw ExcCLIDMismatch.

◆ toPersistent()

template<class STORABLE >

bool DataLink< STORABLE >::toPersistent ( )

Prepare the object to be written out.

◆ toPersistentNoRemap()

bool DataLinkBase::toPersistentNoRemap ( )

inherited

Prepare this link for writing.

One of the toPersistent methods should be called before trying to write the link with root.

Ensures the hashed SG key to be saved is correct. If this link is referencing an object not in SG, we throw ExcPointerNotInSG.

This version does not perform link remapping.

Returns true.

◆ toStorableObject() [1/4]

void DataLinkBase::toStorableObject	(	const_pointer_t	obj,
		CLID	clid_in,
		IProxyDict *	sg
	)

protectedinherited

Set the link to an object given by a pointer.

Parameters

obj	Pointer to the object.
link_clid	CLID of the link being set.
sg	Associated store.

Returns: The SG key for this object.

If sg is 0, then we take the store from whatever the link's currently set to. If the link has no current store, then we take the global default.

May throw ExcCLIDMismatch.

◆ toStorableObject() [2/4]

template<class STORABLE >

void DataLink< STORABLE >::toStorableObject ( const_reference data )

Set the link to a data object that's already in the event.

◆ toStorableObject() [3/4]

template<class STORABLE >

void DataLink< STORABLE >::toStorableObject	(	const_reference	data,
		const EventContext &	ctx
	)

Set the link to an object given by a reference.

Parameters

data	The object to which to link.
ctx	Event context for this link.

◆ toStorableObject() [4/4]

template<class STORABLE >

void DataLink< STORABLE >::toStorableObject	(	const_reference	data,
		IProxyDict *	sg = `0`
	)

Set the link to an object given by a reference.

Parameters

data	The object to which to link.
sg	Associated store.

If sg is 0, then we take the store from whatever the link's currently set to. If the link has no current store, then we take the global default.

◆ toTransient() [1/7]

template<class STORABLE >

virtual bool DataLink< STORABLE >::toTransient ( )

privatevirtual

Reset the object's internal cache.

Implements DataLinkBase.

◆ toTransient() [2/7]

template<class STORABLE >

bool DataLink< STORABLE >::toTransient ( const EventContext & ctx )

Finish initialization after link has been read.

Parameters

ctx	Event context for this link.

This should be called after a link has been read by root in order to set the proxy pointer. Returns true.

◆ toTransient() [3/7]

bool DataLinkBase::toTransient	(	const ID_type &	dataID,
		CLID	link_clid,
		const EventContext &	ctx
	)

inherited

Finish initialization like the link as just been read from root, but with a specified key.

Parameters

dataID	Key of the object.
link_clid	CLID of the link being set.
ctx	Event context for this link.

The link should be clear before this is called. Returns true.

◆ toTransient() [4/7]

bool DataLinkBase::toTransient	(	const ID_type &	dataID,
		CLID	link_clid,
		IProxyDict *	sg = `0`
	)

inherited

Finish initialization like the link as just been read from root, but with a specified key.

Parameters

dataID	Key of the object.
link_clid	CLID of the link being set.
sg	Associated store.

The link should be clear before this is called. Returns true.

If sg is 0, then we use the global default store.

◆ toTransient() [5/7]

template<class STORABLE >

bool DataLink< STORABLE >::toTransient	(	const ID_type &	dataID,
		const EventContext &	ctx
	)

Finish initialization like the link as just been read from root, but with a specified key.

Parameters

dataID	Key of the object.
ctx	Event context for this link.

The link should be clear before this is called. Returns true.

◆ toTransient() [6/7]

template<class STORABLE >

bool DataLink< STORABLE >::toTransient	(	const ID_type &	dataID,
		IProxyDict *	sg = `0`
	)

Finish initialization like the link as just been read from root, but with a specified key.

Parameters

dataID	Key of the object.
sg	Associated store.

The link should be clear before this is called. Returns true.

If sg is 0, then we use the global default store.

◆ toTransient() [7/7]

template<class STORABLE >

bool DataLink< STORABLE >::toTransient ( IProxyDict * sg = 0 )

Finish initialization after link has been read.

Parameters

sg	Associated store.

This should be called after a link has been read by root in order to set the proxy pointer. Returns true.

If sg is 0, then we use the global default store.

Member Data Documentation

◆ m_event [1/2]

template<class STORABLE >

xAOD::TVirtualEvent* DataLink< STORABLE >::m_event

private

Pointer to the event object.

Definition at line 150 of file A/AthLinks/DataLink.h.

◆ m_event [2/2]

template<class STORABLE >

ROOT_SELECTION_NS::MemberAttributes< kTransient > DataLink< STORABLE >::m_event

Declare m_event as transient.

Definition at line 173 of file A/AthLinks/DataLink.h.

◆ m_isDirectIO

bool DataLinkBase::m_isDirectIO

protectedinherited

A transient variable signalling when direct I/O is happening.

This flag is used exclusively by the DataLink<>::toTransient() function to know when it should take the persistent data stored in this object into account. That function may be called in normal P->T conversions as well, in which case using the data from this class would just reset the object to its default state.

Definition at line 60 of file A/AthLinks/DataLinkBase.h.

◆ m_object [1/2]

template<class STORABLE >

const_pointer DataLink< STORABLE >::m_object

mutableprivate

Cached pointer to the object.

Definition at line 148 of file A/AthLinks/DataLink.h.

◆ m_object [2/2]

template<class STORABLE >

ROOT_SELECTION_NS::MemberAttributes< kTransient > DataLink< STORABLE >::m_object

Declare m_object as transient.

Definition at line 171 of file A/AthLinks/DataLink.h.

◆ m_persKey [1/2]

uint32_t DataLinkBase::m_persKey

protectedinherited

Key/identifier of the referenced object.

Definition at line 50 of file A/AthLinks/DataLinkBase.h.

◆ m_persKey [2/2]

sgkey_t DataLinkBase::m_persKey

privateinherited

The hashed key for this link.

Definition at line 341 of file AthLinks/DataLinkBase.h.

◆ m_proxy

SG::DataProxyHolder DataLinkBase::m_proxy

privateinherited

SG proxy for this link.

Definition at line 344 of file AthLinks/DataLinkBase.h.

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

AthLinks/DataLink.h

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Private Types

Private Member Functions

Private Attributes

Accessors.

Detailed Description

template<class STORABLE> class DataLink< STORABLE >

Member Typedef Documentation

◆ __attribute__ [1/2]

◆ __attribute__ [2/2]

◆ castfn_t

◆ const_pointer [1/2]

◆ const_pointer [2/2]

◆ const_pointer_t

◆ const_reference [1/2]

◆ const_reference [2/2]

◆ DictSel

◆ ID_type [1/2]

◆ ID_type [2/2]

◆ pointer

◆ pointer_t

◆ reference

◆ self

◆ sgkey_t [1/2]

◆ sgkey_t [2/2]

◆ value_type [1/2]

◆ value_type [2/2]

Constructor & Destructor Documentation

◆ DataLink() [1/17]

◆ DataLink() [2/17]

◆ DataLink() [3/17]

◆ DataLink() [4/17]

◆ DataLink() [5/17]

◆ DataLink() [6/17]

◆ DataLink() [7/17]

◆ DataLink() [8/17]

◆ DataLink() [9/17]

◆ DataLink() [10/17]

◆ DataLink() [11/17]

◆ DataLink() [12/17]

◆ DataLink() [13/17]

◆ DataLink() [14/17]

◆ DataLink() [15/17]

◆ DataLink() [16/17]

◆ DataLink() [17/17]

Member Function Documentation

◆ classID()

◆ clear() [1/2]

◆ clear() [2/2]

◆ cptr() [1/2]

◆ cptr() [2/2]

◆ dataID()

◆ findIdentifier()

◆ getDataNonConstPtr()

◆ getDataPtr()

◆ isDefault() [1/2]

◆ isDefault() [2/2]

◆ isValid() [1/2]

◆ isValid() [2/2]

◆ key()

◆ operator bool()

◆ operator const_pointer() [1/2]

◆ operator const_pointer() [2/2]

◆ operator!() [1/2]

◆ operator!() [2/2]

◆ operator!=()

◆ operator*() [1/2]

◆ operator*() [2/2]

◆ operator->() [1/2]

◆ operator->() [2/2]

◆ operator==()

◆ persKey()

◆ proxy()

◆ setPersKey()

◆ source()

template<class STORABLE>
class DataLink< STORABLE >

◆ attribute [1/2]

◆ attribute [2/2]