CollHandle< T > Class Template Reference

#include <CollHandle.h>

Public Member Functions
	CollHandle (const edm::InputTag &tag, bool failIfNotFound=true, bool notFoundWarn=true)
const T &	operator* () const
const T *	operator-> () const
void	read (const edm::Event &event)
void	setToken (edm::ConsumesCollector &collector)
edm::InputTag	tag () const

Private Attributes
const T *	currentColl_
const T	emptyColl_
bool	failIfNotFound_
bool	notFoundAlreadyWarned_
bool	notFoundWarn_
const edm::InputTag	tag_
edm::EDGetTokenT< T >	token_

Detailed Description

template<class T>
class CollHandle< T >

Utilitity class for handling an EDM data collection. This class acts as a wrapper of the EDM collection.

An InputTag indentifying the collection is passed to the constructor. The collection is retrieved from the event by a call to the read() method. The CollHandle class instance can then be used as a pointer to the retrieved collection.

Absence of the collection from the event can be optionnaly tolerated: see failIfNotFound parameter of the CollHandle() constructor.

In case the collection was not (yet) retrieved from the collection, it acts as a pointers to an empty collection.

The templace parameter T specifies the type of the data collection.

Definition at line 25 of file CollHandle.h.

Constructor & Destructor Documentation

template<class T>

CollHandle< T >::CollHandle ( const edm::InputTag &  tag, bool  failIfNotFound = true, bool  notFoundWarn = true  )

inline

Constructs a CollHandle.

Parameters

tag	InputTag identifying the data collection
failIfNotFound	pass true if the absence of the collection in the event must be considered as an error. See read() method.

Definition at line 33 of file CollHandle.h.

                                  : tag_(tag),
                                        token_(),
                    currentColl_(&emptyColl_),
                    notFoundAlreadyWarned_(false),
                    failIfNotFound_(failIfNotFound),
                    notFoundWarn_(notFoundWarn){}

Member Function Documentation

template<class T>

const T& CollHandle< T >::operator* ( void  ) const

inline

Gets the collection retrieved by read() method. If the collection was absent from the event an empty collection is returned.

Definition at line 94 of file CollHandle.h.

{ return *currentColl_;}

template<class T>

const T* CollHandle< T >::operator-> ( ) const

inline

Accessor to a member of the collection retrieved by read method(). Considering h a CollHandle instance, h->f() is equivalent to (*h).f().

Definition at line 89 of file CollHandle.h.

{ return currentColl_;}

template<class T>

void CollHandle< T >::read ( const edm::Event &  event )

inline

Retrieves the collection from the event. If failIfNotFound is true and the collection is not found, then an edm::Exception is thrown. For other case of exception throw see edm::Event::getByToken() method documentation. If failIfNotFound is false and the collection is not found, an empty collection is used; a warn message will be logged the first time the collection is not found.

Parameters

event

the EDM event the collection must be retrieved from.

Definition at line 62 of file CollHandle.h.

Referenced by EcalSelectiveReadoutValidation::readAllCollections().

                                  {
    //    try{
    edm::Handle<T> hColl;
    event.getByToken(token_, hColl);
  
    //If we must be tolerant to product absence, then
    //we must check validaty before calling Handle::operator*
    //to prevent exception throw:
    if(!failIfNotFound_     // product-not-found tolerant mode
       && !hColl.isValid()){// and the product was not found
      if(notFoundWarn_
     && !notFoundAlreadyWarned_){//warning logged only once
    edm::LogWarning("ProductNotFound") << tag_
                       << " product "
          "of type '" << typeid(T).name() << "' was not found!";
    notFoundAlreadyWarned_ = true;
      }
      currentColl_ = &emptyColl_;
    } else {
      currentColl_ = &(*hColl);
    }
  }

template<class T>

void CollHandle< T >::setToken ( edm::ConsumesCollector &  collector )

inline

Definition at line 49 of file CollHandle.h.

Referenced by EcalSelectiveReadoutValidation::EcalSelectiveReadoutValidation().

  {
    token_ = collector.consumes<T>(tag_);
  }

template<class T>

edm::InputTag CollHandle< T >::tag ( ) const

inline

Definition at line 96 of file CollHandle.h.

{ return tag_; }

Member Data Documentation

template<class T>

const T* CollHandle< T >::currentColl_

private

Pointer to the last read collection, points to emptColl be default

Definition at line 112 of file CollHandle.h.

Referenced by CollHandle< EEDigiCollection >::operator*(), CollHandle< EEDigiCollection >::operator->(), and CollHandle< EEDigiCollection >::read().

template<class T>

const T CollHandle< T >::emptyColl_

private

An empty collection used as default when the collection was not retrieved from the event.

Definition at line 117 of file CollHandle.h.

Referenced by CollHandle< EEDigiCollection >::read().

template<class T>

bool CollHandle< T >::failIfNotFound_

private

Switch for collection absence toleration.

Definition at line 125 of file CollHandle.h.

Referenced by CollHandle< EEDigiCollection >::read().

template<class T>

bool CollHandle< T >::notFoundAlreadyWarned_

private

Used to emit warn message in case of collection absence only once.

Definition at line 121 of file CollHandle.h.

Referenced by CollHandle< EEDigiCollection >::read().

template<class T>

bool CollHandle< T >::notFoundWarn_

private

Switch for the warning in case of not found collection

Definition at line 129 of file CollHandle.h.

Referenced by CollHandle< EEDigiCollection >::read().

template<class T>

const edm::InputTag CollHandle< T >::tag_

private

tag identifying the data collecion

Definition at line 105 of file CollHandle.h.

Referenced by CollHandle< EEDigiCollection >::read(), CollHandle< EEDigiCollection >::setToken(), and CollHandle< EEDigiCollection >::tag().

template<class T>

edm::EDGetTokenT<T> CollHandle< T >::token_

private

Definition at line 108 of file CollHandle.h.

Referenced by CollHandle< EEDigiCollection >::read(), and CollHandle< EEDigiCollection >::setToken().