StepHandler is the base class for implementing any model for a step in the event generation chain. More...

#include <StepHandler.h>

Inheritance diagram for ThePEG::StepHandler:

Public Member Functions
Standard constructors and destructors.
virtual	~StepHandler ()
	The destructor.
Virtual functions to be implemented by concrete sub-classes.
virtual void	handle (EventHandler &eh, const tPVector &tagged, const Hint &hint)=0
	The main function called by the EventHandler class to perform a step.
Access to the calling EventHandler and current Step.
tEHPtr	eventHandler () const
	Get a pointer to the EventHandler which made the last call to handle().
void	eventHandler (tEHPtr)
	Set a pointer to the EventHandler which made the last call to handle().
tStepPtr	newStep ()
	Return a pointer to a new step.
tStepPtr	currentStep ()
	If a new step has been created, return it, otherwise return the current step from the eventHandler().

Static Public Member Functions
static void	Init ()
	Standard Init function used to initialize the interface.

Protected Member Functions
void	createNewStep ()
	Use the collision handler to create a new step.

Private Member Functions
StepHandler &	operator= (const StepHandler &)
	Private and non-existent assignment operator.

Private Attributes
tEHPtr	theEventHandler
	A pointer to the (partial) collision handler which made the current call to handle().
tStepPtr	theNewStep
	A pointer to a new step if created in the last call to handle().
tStepPtr	theCurrentStep
	A pointer to the current step.

Static Private Attributes
static AbstractNoPIOClassDescription < StepHandler >	initStepHandler
	Describe an abstract class without persistent data.

Detailed Description

StepHandler is the base class for implementing any model for a step in the event generation chain.

It has one main virtual method, handle(), which should be overridden by sub classes. The handle method is given a reference to a EventHandler, a vector of particles and a Hint as arguments. The handler is only allowed to treat particles which are in the vector. The Hint may be cast dynamically to a sub class and do whatever it wishes with the information found there. The EventHandler can be used to add other StepHandlers and Hints to modify the subsequent generation. If the StepHandler actually performs some action, the resulting particles should be added to a new Step which should be aquired with the newStep() function.

See also:: The interfaces defined for StepHandler.; EventHandler; Hint; Step

Definition at line 41 of file StepHandler.h.

Member Function Documentation

virtual void ThePEG::StepHandler::handle	(	EventHandler &	eh,
		const tPVector &	tagged,
		const Hint &	hint
	)

pure virtual

The main function called by the EventHandler class to perform a step.

Parameters:

eh	the EventHandler in charge of the Event generation.
tagged	if not empty these are the only particles which should be considered by the StepHandler.
hint	a Hint object with possible information from previously performed steps.

Exceptions:

Veto	if the StepHandler requires the current step to be discarded.
Stop	if the generation of the current Event should be stopped after this call.
Exception	if something goes wrong.

Implemented in ThePEG::ClusterCollapser, ThePEG::CascadeHandler, and ThePEG::DecayHandler.

tStepPtr ThePEG::StepHandler::newStep ( )

inline

Return a pointer to a new step.

If one has alredy been created in the last call to handle(), that step will be returned.

Definition at line 93 of file StepHandler.h.

References createNewStep(), and theNewStep.