class AtlSelector: public TSelector

 Default constructor

 Default destructor

 Set output tree/ntuple

 If the name of the output tree is set it is automatically being
 filled with all events passing the ProcessCut() method.

 The trigger configuration dbase of the used runs is also copied
 from the input files.

 If the size of the output tree exceeds the maximum tree size
 (see TTree::SetMaxTreeSize()) of (currently) 2Gb, Root splits
 the output file automatically. Iin contrast to Root's internal
 mechanism, which writes all histograms to the last of the
 splitted files only, the AtlSelector class splits also the
 histograms and writes them to their corresponding output files
 (see ChangeOutputFile()). The same holds for the trigger
 configuration dbase.

 Set branch assignments of the input tree. Here an A++ input
 tree is assumed. For other trees this (virtual) method has to
 be overloaded. See also the GetEntry() method

 Get entry from current input tree. This (virtual) method can be
 overloaded if needed (different type of input tree)

 The Init() function is called when the selector needs to initialize
 a new tree or chain. Typically here the branch addresses and branch
 pointers of the tree will be set.
 It is normally not necessary to make changes to the generated
 code, but the routine can be extended by the user if needed.
 Init() will be called many times when running on PROOF
 (once per file to be processed).

 The Notify() function is called when a new file is opened. This
 can be either for a new TTree in a TChain or when a new TTree
 is started when using PROOF.

 Load the configurations (trigger etc.) from the
 newly opened file. In case of writing an event list make sure a
 new one is appended for the current tree.

 At the end of this function, the Notify() functions of the
 current event reader and all active tools are called.

 Perform bookkeeping of the cut-flow and job info histograms.
 This is done for every input file.

 The Begin() function is called at the start of the query.
 When running with PROOF Begin() is only called on the client.
 The tree argument is deprecated (on PROOF 0 is passed).

 The SlaveBegin() function is called after the Begin() function.
 When running with PROOF SlaveBegin() is called on each slave server.
 The tree argument is deprecated (on PROOF 0 is passed).

 Function called before starting the event loop
  -it performs some cleanup
  -it creates histograms
  -it sets some initialisation for the event list

 The Process() function is called for each entry in the tree (or possibly
 keyed object in the case of PROOF) to be processed. The entry argument
 specifies which entry in the currently loaded tree is to be processed.
 It can be passed to either AtlSelector::GetEntry() or
 TBranch::GetEntry() to read either all or the required parts of
 the data. When processing keyed objects with PROOF, the object
 is already loaded and is available via the fObject pointer.

 This function should contain the "body" of the analysis. It can contain
 simple or elaborate selection criteria, run algorithms on the data
 of the event and typically fill histograms.

 The processing can be stopped by calling Abort().

 Use fStatus to set the return value of TTree::Process().

 The return value is currently not used.

 The SlaveTerminate() function is called after all entries or objects
 have been processed. When running with PROOF SlaveTerminate() is called
 on each slave server.

 The Terminate() function is the last function to be called during
 a query. It always runs on the client, it can be used to present
 the results graphically or save the results to file.

 Event fill routine (histograms etc)

 Set Default Values for public member variables.
 When implementing this virtual method in a derived
 Selector class, make sure to call this base method
 as well.
 SetCutDefaults should be called in the ctor of the
 derived class.

 void DerivedSelector::SetCutDefaults(){
   AtlSelector::SetCutDefaults(); // calls base portion
   fFoo = bar; // set default value of fFoo to bar

 }

 Print information about the current process.  For interactive
 (ie non-batch) jobs continuous output is given while for batch
 jobs only a few out is given to avoid too much junk in the log
 file

 Print summary at end of job

 Add analysis tool to list of tools

 Retrieves Tool from fListOfTools
 If parameter force is true, the method will abort if no tool with
 the description is found
 otherwise it won't bother and simply return 0

 Load trigger configuration

 Book histograms containing information about the analysis job
 like the no. of processed events, the event weights etc.

 The binning for the nevt histogram is as follows:
 Bin  1 : All unfiltered events (unweighted)
 Bin  2 : All unfiltered events (MC weight only)
 Bin  3 : All unfiltered events (all weights)
 Bin  4 : Processed events (unweighted)
 Bin  5 : Processed events (MC weight only)
 Bin  6 : Processed events (all weights)
 Bin  7 : Pre-accepted events by ProcessPreCut() (unweighted)
 Bin  8 : Pre-accepted events by ProcessPreCut() (MC weights only)
 Bin  9 : Pre-accepted events by ProcessPreCut() (all weights)
 Bin 10 : Accepted events by ProcessCut() (unweighted)
 Bin 11 : Accepted events by ProcessCut() (MC weight only)
 Bin 12 : Accepted events by ProcessCut() (all weights)

 This method is used to prevent Root from wrinting all
 histograms only to the last file in case of splited output
 files (see TTree::ChangeFile()). Instead the histograms are
 splitted as well and written to their corresponding output
 file.

 Get Jet Multiplicity label

 Returns Jet Multiplicity label ('1', '2', ...)

 Get Lepton Label

 Works only for single-leptons

 Returns Lepton Channel Label

 Clear AtlSelector

 User has to call this function in derived selector

 Get Jet Multiplicity Enum ('kOneJet', 'kTwoJet', ...)

 Get Lepton Channel Enum ('kElectron', 'kMuon', ...)

 Print configuration of base selector.
 (this function is supposed to be used from inside the user
 analysis Print()

 Explcitly sets the event reader.
 Ownership of the reader is transferred to AtlSelector!

 Sets the input mode.
 Deprecated, please use SetEvtReader() if possible.

 Is there an A++ tree written to the output .root file ?

 Switch for printing every event
 (useful for testing/debugging)

 Switch for printing the Root's object table
 (useful for tracking memory leaks)