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#include <FWCore/Framework/interface/EDLooperBase.h>
Description: Base class for all looping components
This abstract class forms the basis of being able to loop through a list of events multiple times. In general the class EDLooper is more appropriate for looping sequentially over events.
The class uses a Template Pattern to describe the structure of a loop. The structure is made up of three phases 1) start of loop At the start of a new loop the virtual method 'startingNewLoop(unsigned int)' is called. The integer passed is the number of loops which have been run in the job starting at index 0. 2) during loop Each time an event has been processed by all other modules in a job, the method Status duringLoop(Event const&, EventSetup const&, ProcessingController&) will be called. The return value 'Status' can be either kContinue if you want to proceed to the 'next' event or kStop if you want to stop this particular loop. The class ProcessingController allows you further control of what is meant by 'next' event. By default 'next' event will just be the next event in the normal sequence. However, for sources which support the feature, you can also use ProcessingController to make the 'next' event be the 'event before the last processed event' (i.e. go back one) or to use an EventID to exactly specify what next event you want. However, if you say to go 'back' one event while the job is on the first event of the loop or pass an EventID for an event not contained in the source the job will immediately go to 'end of loop'. NOTE: if you have no need of controlling exactly what 'next' event should be processed then you should instead inherit from the subclass EDLooper and us it simplified interface for 'duringLoop'. 3) end of loop Once all events have been processed or kStop was returned from 'duringLoop' or ProcessingController was told to go to an 'invalid' event then the method Status endOfLoop(EventSetup const&, unsigned int iCounter) will be called. iCounter will be the number of loops which have been run in the job starting at index 0. If kContinue is returned from endOfLoop then a new loop will begin else if kStop is called then the job will end.
Like other modules, an EDLooperBase is called for 'beginJob', 'endJob', 'beginRun', 'endRun', 'beginLuminosityBlock' and 'endLuminosityBlock'.
Additional information and control of a job is possible via the interfaces: attachTo(ActivityRegistry&) : via the ActivityRegistry you can monitor exactly which modules are being run scheduleInfo(): returns a ScheduleInfo which you can use to determine what paths are in a job and what modules are on each path. moduleChanger(): returns a ModuleChanger instance which can be used to modify the parameters of an EDLooper or EDFilter. Such modifications can only occur during a call to 'endOfLoop' since the newly changed module can only be properly initialized at the start of the next loop.
1.8.5
