a (simplified) python wrapper for StoreObjPtr. More...

#include <PyStoreObj.h>

Collaboration diagram for PyStoreObj:

[legend]

Public Member Functions
	PyStoreObj (const std::string &name, DataStore::EDurability durability=DataStore::EDurability::c_Event)
	constructor. More...

	PyStoreObj (TClass *objClass, DataStore::EDurability durability=DataStore::EDurability::c_Event)
	constructor. More...

	PyStoreObj (TClass *objClass, const std::string &name, DataStore::EDurability durability=DataStore::EDurability::c_Event)
	constructor. More...

bool	registerInDataStore (DataStore::EStoreFlags storeFlags)
	Register the object in the DataStore. More...

bool	registerInDataStore (const std::string &name="", DataStore::EStoreFlags storeFlags=DataStore::EStoreFlags::c_WriteOut)
	Register the object in the DataStore. More...

bool	isRequired (const std::string &name="")
	Ensure this object has been registered previously. More...

bool	isOptional (const std::string &name="")
	Tell the DataStore about an optional input. More...

bool	hasValidClass () const
	Check whether a TClass for the contained object could be determined.

bool	isValid () const
	Check whether the object was registered and created.

	operator bool () const
	Does this PyStoreObj contain a valid datastore object? More...

TObject *	obj () const
	Returns the attached DataStore object, or nullptr if no valid object exists.

TObject *	operator-> () const
	Returns the attached DataStore object, or nullptr if no valid object exists.

bool	assign (TObject *object, bool replace=false)
	Assign 'object' to the accessor. More...

bool	create (bool replace=false)
	Create default constructed object in the DataStore. More...

Static Public Member Functions
static std::vector< std::string >	list (DataStore::EDurability durability=DataStore::EDurability::c_Event)
	Return list of available objects for given durability.

static void	printList (DataStore::EDurability durability=DataStore::EDurability::c_Event)
	Print list of available objects for given durability.

Private Member Functions
void	ensureAttached () const
	Ensure that contained TObject has been attached to a memory location on the DataStore.

void	attach () const
	Lookup the store entry and cache a pointer to it.

Private Attributes
StoreAccessorBase	m_storeAccessor
	Store accessor to retrieve the object.

StoreEntry *	m_storeEntry = nullptr
	Pointer to the DataStore entry - serves as an internal cache omitting repeated look up from the DataStore.

Detailed Description

a (simplified) python wrapper for StoreObjPtr.

Compared to StoreObjPtr, PyStoreObj returns only TObjects (since it doesn't use templates). Thanks to Python, you can still access all public functions and data members of the actual type.

You can check the runtime type information of the returned objects by using Python's built-in type() function.

Usage example

Inside a Python module's event() function, you can access DataStore objects like this:

from ROOT import Belle2
evtmetadata = Belle2.PyStoreObj('EventMetaData')
# Alternatively: evtmetadata = Belle2.PyStoreObj(Belle2.EventMetaData.Class())
if not evtmetadata:
  B2ERROR("No EventMetaData found");
else:
  event = evtmetadata.getEvent()
  # alternatively: evtmetadata.obj().getEvent()

Most of the time you can just use the PyStoreObj instance like an instance of the class it represents, i.e. call all the members. The only exceptions are if the class has members which are also present in PyStoreObj (for example isValid() or isRequired()). In this case you need to use the obj() member to obtain a reference to the real object first as shown in the example.

Creating objects

You can also create new objects in your Python basf2 module, using registerInDataStore() and create(). Since you cannot specify the type directly, as with template arguments to StoreObjPtr, the class name is assumed to be identical to the 'name' argument given to the constructor, and to reside in the Belle2 namespace. Consequently, you can only create objects with their default names.

See display/examples/displaydata.py for a concrete example.

See also: PyStoreArray and the Conditions Data interface classes PyDBObj and PyDBArray

Definition at line 67 of file PyStoreObj.h.

Constructor & Destructor Documentation

◆ PyStoreObj() [1/3]

PyStoreObj	(	const std::string &	name,
		DataStore::EDurability	durability = `DataStore::EDurability::c_Event`
	)

explicit

constructor.

Parameters

name	Name of the entry to be accessed
durability	0: event, 1: persistent

Definition at line 40 of file PyStoreObj.cc.

                                                        :
   PyStoreObj(replaceNullPtr(DataStore::getTClassFromDefaultObjectName(name),
                             TObject::Class()),
              /* Default to TObject for unknown class for backwards compatability */
              name,
              durability)
 {
 }

◆ PyStoreObj() [2/3]

PyStoreObj	(	TClass *	objClass,
		DataStore::EDurability	durability = `DataStore::EDurability::c_Event`
	)

explicit

constructor.

Parameters

objClass	Class of the object to be accessed
durability	0: event, 1: persistent

Definition at line 50 of file PyStoreObj.cc.

◆ PyStoreObj() [3/3]

PyStoreObj	(	TClass *	objClass,
		const std::string &	name,
		DataStore::EDurability	durability = `DataStore::EDurability::c_Event`
	)

explicit

constructor.

Parameters

objClass	Class of the object to be accessed
name	Name of the entry to be accessed
durability	0: event, 1: persistent

Definition at line 56 of file PyStoreObj.cc.

Member Function Documentation

◆ assign()

bool assign	(	TObject *	object,
		bool	replace = `false`
	)

Assign 'object' to the accessor.

(takes ownership).

Parameters

object	The object that should be put in the DataStore, should be of same type as the one used by this accessor.
replace	Should an existing object be replaced? (if existing and supplied object are equal, this has no effect)

Returns: True if the assignment succeeded. If false, assign() will delete 'object', do not use it afterwards.

Definition at line 140 of file PyStoreObj.cc.

◆ create()

bool create ( bool replace = false )

Create default constructed object in the DataStore.

Parameters

replace Should an existing object be replaced?

Returns: True if the creation succeeded.

Definition at line 103 of file PyStoreObj.cc.

◆ isOptional()

bool isOptional ( const std::string & name = "" )

Tell the DataStore about an optional input.

Mainly useful for creating diagrams of module inputs and outputs. This must be called in the initialization phase.

Parameters

name	If not empty, use non-default name for this object.

Returns: True if the object exists.

Definition at line 87 of file PyStoreObj.cc.

◆ isRequired()

bool isRequired ( const std::string & name = "" )

Ensure this object has been registered previously.

Will cause an ERROR if it does not exist. This must be called in the initialization phase.

Parameters

name	If not empty, use non-default name for this object.

Returns: True if the object exists.

Definition at line 82 of file PyStoreObj.cc.

◆ operator bool()

operator bool ( ) const

inline

Does this PyStoreObj contain a valid datastore object?

Accessing the object's data is UNSAFE if this returns false.

Definition at line 145 of file PyStoreObj.h.

145 { return isValid(); }

Belle2::PyStoreObj::isValid

bool isValid() const

Check whether the object was registered and created.

Definition: PyStoreObj.cc:92

◆ registerInDataStore() [1/2]

bool registerInDataStore	(	const std::string &	name = `""`,
		DataStore::EStoreFlags	storeFlags = `DataStore::EStoreFlags::c_WriteOut`
	)

Register the object in the DataStore.

This must be called in the initialization phase, and a TClass or name=class name must have been supplied during construction.

Parameters

name	Name of the entry to be registered. Empty for default name.
storeFlags	ORed combination of DataStore::EStoreFlags. (default: c_WriteOut)

Returns: True if the registration succeeded.

Definition at line 70 of file PyStoreObj.cc.

◆ registerInDataStore() [2/2]

bool registerInDataStore ( DataStore::EStoreFlags storeFlags )

Register the object in the DataStore.

This must be called in the initialization phase.

Parameters

storeFlags ORed combination of DataStore::EStoreFlags. (default: c_WriteOut)

Returns: True if the registration succeeded.

Definition at line 65 of file PyStoreObj.cc.

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

framework/pybasf2/include/PyStoreObj.h
framework/pybasf2/src/PyStoreObj.cc

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Usage example

Creating objects

Constructor & Destructor Documentation

◆ PyStoreObj() [1/3]

◆ PyStoreObj() [2/3]

◆ PyStoreObj() [3/3]

Member Function Documentation

◆ assign()

◆ create()

◆ isOptional()

◆ isRequired()

◆ operator bool()

◆ registerInDataStore() [1/2]

◆ registerInDataStore() [2/2]