xAODTMetaBranch Class Reference

Specialised class for browsing xAOD metadata interface objects in ROOT. More...

#include <xAODTMetaBranch.h>

Inheritance diagram for xAODTMetaBranch:

Collaboration diagram for xAODTMetaBranch:

Public Member Functions
	xAODTMetaBranch (::TTree &parent, xAOD::TEvent &event, const std::type_info &ti, const char *brName, const char *brType)
	Constructor with all the needed parameters. More...
virtual ::Int_t	GetEntry (::Long64_t entry, ::Int_t getall)
	Function getting the current entry/file for this branch. More...
virtual ::TClass *	IsA () const
	Function returning the type of ::TBranchObject. More...

Private Attributes
xAOD::TEvent *	m_event
	Pointer to the TEvent object reading the persistent tree. More...
const std::type_info *	m_ti
	The type of the object that needs to be read. More...
const void *	m_object
	Pointer to the object read in using TEvent. More...

Detailed Description

Specialised class for browsing xAOD metadata interface objects in ROOT.

This is a class extremely similar to xAOD::TEventBranch. But instead of giving access to event level information, it provides a convenient view of the ROOT-readable metadata payload of xAOD files.

Author

Attila Krasznahorkay Attil.nosp@m.a.Kr.nosp@m.aszna.nosp@m.hork.nosp@m.ay@ce.nosp@m.rn.c.nosp@m.h

Definition at line 27 of file xAODTMetaBranch.h.

Constructor & Destructor Documentation

xAODTMetaBranch()

xAODTMetaBranch::xAODTMetaBranch	(	::TTree &	parent,
		xAOD::TEvent &	event,
		const std::type_info &	ti,
		const char *	brName,
		const char *	brType
	)

Constructor with all the needed parameters.

Member Function Documentation

GetEntry()

Int_t xAODTMetaBranch::GetEntry	(	::Long64_t	entry,
		::Int_t	getall
	)

Function getting the current entry/file for this branch.

This is the function doing the heavy lifting.

It loads the interface object for the current file (entry) requested. Only doing some minimal overhead in the meanwhile.

Parameters

entry	The entry/file to be read for this object
getall	When set to 1, read all information about the branch (Not used.)

Returns

The number of bytes read, or a negative number if not successful

Definition at line 32 of file xAODTMetaBranch.cxx.

                                                         {
 
   // Check if the branch is active:
   if( TestBit( kDoNotProcess ) ) {
      return 0;
   }
 
   // Check whether we already have the requested entry:
   if( fReadEntry == entry ) {
      return 1;
   }
 
   // Load the requested file:
   if( m_event->getFile( entry ) < 0 ) {
      Error( "GetEntry",
             XAOD_MESSAGE( "Problems with loading entry/file %lld" ), entry );
      return -1;
   }
 
   // Update the internal pointer:
   m_object = m_event->getInputObject( GetName(), *m_ti, kFALSE, kTRUE );
   if( ! m_object ) {
      Error( "GetEntry",
             XAOD_MESSAGE( "Failed to read variable of type \"%s\" with "
                           "key \"%s\"" ),
             GetClassName(), GetName() );
      return -1;
   }
 
   // We were successful:
   fReadEntry = entry;
   return 1;
}

IsA()

TClass * xAODTMetaBranch::IsA

(

)

const

Function returning the type of ::TBranchObject.

I took this from the ARA code directly.

Apparenly TTree would not know how to handle this object if it reported its actual type. So we pretend that this is a TBranchObject object. That way TBrowser shows its contents nicely.

Returns

The class for TBranchObject

Definition at line 73 of file xAODTMetaBranch.cxx.

                                   {
 
   return ::TBranchObject::IsA();
}

Member Data Documentation

m_event

xAOD::TEvent* xAODTMetaBranch::m_event

private

Pointer to the TEvent object reading the persistent tree.

Definition at line 47 of file xAODTMetaBranch.h.

m_object

const void* xAODTMetaBranch::m_object

private

Pointer to the object read in using TEvent.

Definition at line 51 of file xAODTMetaBranch.h.

m_ti

const std::type_info* xAODTMetaBranch::m_ti

private

The type of the object that needs to be read.

Definition at line 49 of file xAODTMetaBranch.h.

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

• xAODTMetaBranch.h
• xAODTMetaBranch.cxx