Detailed Description

Extended version of ROOT THashList.

Created by KVClassFactory on Mon Nov 30 15:00:00 2009 Author: John Frankland,,,

This collection class uses a THashList for quick look-up of objects based on the TString::Hash() value of their name, and adds all the extra functionality defined in KVSeqCollection.

Automatic rehashing of the list is enabled by default (with rehash level = 2), unlike THashList (disabled by default). Beware if objects' names change or are changed after being added to the list: a manual Rehash() is required.

Sorting the list

As THashList::Sort() is defined, we implemented a KVHashList::Sort() method which takes exactly the same argument as THashList::Sort().

Examples: MicroStat_example2.C.

Definition at line 29 of file KVHashList.h.

#include <KVHashList.h>

Inheritance diagram for KVHashList:

[legend]

Public Member Functions
	KVHashList (Int_t capacity=TCollection::kInitHashTableCapacity, Int_t rehash=2)

virtual	~KVHashList ()
	Destructor. More...

Float_t	AverageCollisions () const

template<typename T >
Bool_t	ContainsObjectWithName (const T &o)

const TList *	GetListForObject (const char *name) const

const TList *	GetListForObject (const TObject *obj) const

void	Rehash (Int_t newCapacity=0)

void	Sort (Bool_t order=kSortAscending)

Public Member Functions inherited from KVSeqCollection
	KVSeqCollection ()
	Default constructor. More...

	KVSeqCollection (const Char_t *collection_classname)

	KVSeqCollection (const KVSeqCollection &)

virtual	~KVSeqCollection ()

virtual void	Add (TObject *obj)

virtual void	AddAfter (const TObject after, TObject obj)

virtual void	AddAt (TObject *obj, Int_t idx)

virtual void	AddBefore (const TObject before, TObject obj)

virtual void	AddFirst (TObject *obj)

virtual void	AddLast (TObject *obj)

virtual TObject *	After (const TObject *obj) const

virtual TObject *	At (Int_t idx) const

virtual TObject *	Before (const TObject *obj) const

virtual void	Clear (Option_t *option="")

const Char_t *	CollectionClassName () const

virtual void	Copy (TObject &obj) const

virtual void	Delete (Option_t *option="")

virtual void	Execute (const char method, const char params, Int_t *error=0)

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)

virtual TObject *	FindObject (const char *name) const

virtual TObject *	FindObject (const TObject *obj) const

virtual TObject *	FindObjectAny (const Char_t att, const Char_t keys, Bool_t contains_all=kFALSE, Bool_t case_sensitive=kTRUE) const

TObject *	FindObjectByClass (const Char_t *) const
	Return (first) object in embedded list with given class. More...

TObject *	FindObjectByClass (const TClass *) const
	Return (first) object in embedded list with given class. More...

virtual TObject *	FindObjectByLabel (const Char_t *) const

virtual TObject *	FindObjectByName (const Char_t *name) const

virtual TObject *	FindObjectByNumber (UInt_t num) const

virtual TObject *	FindObjectByTitle (const Char_t *) const
	Will return object with given title (value of TObject::GetTitle() method). More...

virtual TObject *	FindObjectByType (const Char_t *) const

virtual TObject *	FindObjectWithMethod (const Char_t retvalue, const Char_t method) const

virtual TObject *	FindObjectWithNameAndType (const Char_t name, const Char_t type) const

virtual TObject *	First () const

template<typename T >
T *	get_object (const TString &name) const

TSeqCollection *	GetCollection () const

virtual TObject **	GetObjectRef (const TObject *obj) const
	Return reference to object. More...

virtual Int_t	GetSize () const

KVSeqCollection *	GetSubListWithClass (const Char_t *class_name) const

KVSeqCollection *	GetSubListWithClass (const TClass *_class) const

KVSeqCollection *	GetSubListWithLabel (const Char_t *retvalue) const

KVSeqCollection *	GetSubListWithMethod (const Char_t retvalue, const Char_t method) const

KVSeqCollection *	GetSubListWithName (const Char_t *retvalue) const

KVSeqCollection *	GetSubListWithType (const Char_t *retvalue) const

virtual Bool_t	IsCleanup () const

virtual Bool_t	IsSendingModifiedSignals () const

virtual Bool_t	IsSortable () const

virtual Bool_t	IsSorted () const

virtual TObject *	Last () const

virtual TIterator *	MakeIterator (Bool_t dir=kIterForward) const
	Make and return iterator for the list. More...

virtual void	Modified ()

KVSeqCollection &	operator= (const KVSeqCollection &)

virtual void	RecursiveRemove (TObject *obj)

virtual TObject *	Remove (TObject *obj)
	Remove object from list. More...

virtual void	SendModifiedSignals (Bool_t yes=kTRUE)

virtual void	SetCleanup (Bool_t enable=kTRUE)

virtual void	SetOwner (Bool_t enable=kTRUE)

Additional Inherited Members
Static Public Member Functions inherited from KVSeqCollection
static KVSeqCollection *	MakeListFromFile (TFile *file)

static KVSeqCollection *	MakeListFromFileWithClass (TFile file, const Char_t class_name)

static KVSeqCollection *	MakeListFromFileWithClass (TFile file, const TClass _class)

static KVSeqCollection *	MakeListFromFileWithMethod (TFile file, const Char_t retvalue, const Char_t *method)

static void	RehashCleanupList ()

Constructor & Destructor Documentation

◆ KVHashList()

KVHashList::KVHashList	(	Int_t	capacity = `TCollection::kInitHashTableCapacity`,
		Int_t	rehash = `2`
	)

Create a THashList object. Capacity is the initial hashtable capacity (i.e. number of slots), by default kInitHashTableCapacity = 17, and rehash is the value at which a rehash will be triggered. I.e. when the average size of the linked lists at a slot becomes longer than rehash then the hashtable will be resized and refilled to reduce the collision rate to about 1. The higher the collision rate, i.e. the longer the linked lists, the longer lookup will take. The default value of rehash = 2 (minimum allowed value) - automatic rehashing is enabled by default. If rehash=0 the table will NOT automatically be rehashed. Use Rehash() for manual rehashing. WARNING !!! If the name of an object in the HashList is modified, The hashlist must be Rehashed

Definition at line 26 of file KVHashList.cpp.

◆ ~KVHashList()

KVHashList::~KVHashList ( )

virtual

Destructor.

Definition at line 52 of file KVHashList.cpp.

Member Function Documentation

◆ AverageCollisions()

Float_t KVHashList::AverageCollisions ( ) const

Return the average collision rate. The higher the number the longer the linked lists in the hashtable, the slower the lookup. If the number is high, or lookup noticeably too slow, perfrom a Rehash()

Definition at line 64 of file KVHashList.cpp.

◆ ContainsObjectWithName()

template<typename T >

Bool_t KVHashList::ContainsObjectWithName ( const T & o )

inline

Returns true if list contains an object with the same name as o class T must have a method const char* T::GetName() const

Definition at line 48 of file KVHashList.h.

◆ GetListForObject() [1/2]

const TList * KVHashList::GetListForObject ( const char * name ) const

Return the THashTable's list (bucket) in which obj can be found based on its hash; see THashTable::GetListForObject().

Definition at line 121 of file KVHashList.cpp.

◆ GetListForObject() [2/2]

const TList * KVHashList::GetListForObject ( const TObject * obj ) const

Return the THashTable's list (bucket) in which obj can be found based on its hash; see THashTable::GetListForObject().

Definition at line 140 of file KVHashList.cpp.

◆ Rehash()

void KVHashList::Rehash ( Int_t newCapacity = 0 )

Rehash the hashlist.

This needs to be done in two cases:

If the collision rate becomes too high (i.e. the average size of the linked lists become too long - use AverageCollisions() to check if you need to rehash.) then lookup efficiency decreases since relatively long lists have to be searched every time. To improve performance rehash the hashtable, increasing the number of slots. This method resizes the table to newCapacity slots and refills the table.
If the names of any objects in the list CHANGE, you must rehash the list (as the lookup of objects depends on the TString::Hash() value calculated from their name when they are added to the list). In this case it is not necessary to increase the capacity of the list, just call Rehash() with no arguments.

Definition at line 92 of file KVHashList.cpp.

◆ Sort()

void KVHashList::Sort ( Bool_t order = kSortAscending )