FillIterator Class Reference

#include <FillIterator.h>

Inheritance diagram for FillIterator:

[legend]Collaboration diagram for FillIterator:

[legend]List of all members.

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Detailed Description

Abstract base class for iterators used to fill self-filling histograms.

A FillIterator object has to know how many entries for a given event should be made. If, for example, we have n D* meson candidates in an event, operator() should return a value between 0 (first D*) and n-1 (last D*). "-1" means "no D* available, or past the last D*".

To iterate over all values, use code like this (iter is a pointer to a FillIterator, and may be 0, meaning "exactly 1 entry per event"):

  if (!iter || iter->reset()) {
  do {
    if (!cut || (*cut)()) {
      float w = wfun ? (*wfun)() : 1.;
      this->TH1F::Fill ((*xfun)(), w);
    } 
  } while (iter && iter->next());  
 *

If FillIterator objects are used, the corresponding FloatFun and BaseCut objects normally have to store a pointer to the iterator, so that a DStarMass object can ask the iterator the mass of which D* meson is to be plotted.

The destructor is protected to ensure FillIterator objects can only be created on the heap (with "new"). The resulting memory leak is acknowledged.

Normally, a concrete subclass of FillIterator will look something like this:

 class MyIterator: public FillIterator {
 public:
   MyIterator(): index(0) {}
   virtual int getN () const { return NUMBEROFENTRIES;};
   virtual int operator() () const {
     return (index < getN()) ? index : -1;
   }
   virtual bool next() {
     if (index++ >= getN()) {
       index = -1;
       return false;
     }
     return true;
   }
   virtual bool reset() {
     If (getN() <= 0) {
       index = -1;
       return false;
     }
     index = 0;
     return true;
   }
   virtual bool isValid() const {
     return (index >= 0) && index < getN();
   }
 protected:
   ~MyIterator() {};
   int index;
 };

Here getN() has to be implemented in a way that it returns the number of entries, e.g. D* mesons, for the current event. This will typically need a pointer to some Tree entry that contains the number of D* mesons.

Changelog

• 6.7.04 BL: FillIterator derived from IntFun
• 15.7.04 BL: Added method getIterator()
• 22.9.04 BL: Added method isValid()
• 4.6.05 BL: Added constructors with name as argument

Author: Jenny Böhme, Benno List

Date

2005/06/04 16:27:51

Author

blist

Definition at line 90 of file FillIterator.h.

Public Member Functions
	FillIterator (const char *name_="?")
	Constructor from a C style string, serves as default constructor.
	FillIterator (const std::string &name_)
	Constructor from a C++ string.
virtual int	operator() () const=0
	Returns iterator value, starting at 0; "-1" means "invalid".
virtual bool	next ()=0
	Increments iterator; returns false if iterator cannot be incremented.
virtual bool	reset ()=0
	Resets iterator; returns false if iterator value range is empty.
virtual bool	isValid () const=0
	Returns whether current value of iterator is valid.
virtual const FillIterator *	getIterator () const
	Returns pointer to iterator = itself.
Protected Member Functions
virtual	~FillIterator ()
	Protected destructor to ensure creation on the heap.

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Constructor & Destructor Documentation

FillIterator::FillIterator (  const char *  name_ = "?"  )  [inline, explicit]

Constructor from a C style string, serves as default constructor. Parameters: name_  The object's name Definition at line 94 of file FillIterator.h.

FillIterator::FillIterator (  const std::string &  name_  )  [inline, explicit]

Constructor from a C++ string. Parameters: name_  The object's name Definition at line 98 of file FillIterator.h.

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

• FillIterator.h

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