THashList
class description - source file - inheritance tree
public:
THashList THashList(Int_t capacity = TCollection::kInitHashTableCapacity, Int_t rehash = 0)
THashList THashList(TObject* parent, Int_t capacity = TCollection::kInitHashTableCapacity, Int_t rehash = 0)
virtual void ~THashList()
virtual void AddAfter(TObject* after, TObject* obj)
virtual void AddAfter(TObjLink* after, TObject* obj)
virtual void AddAt(TObject* obj, Int_t idx)
virtual void AddBefore(TObject* before, TObject* obj)
virtual void AddBefore(TObjLink* before, TObject* obj)
virtual void AddFirst(TObject* obj)
virtual void AddFirst(TObject* obj, Option_t* opt)
virtual void AddLast(TObject* obj)
virtual void AddLast(TObject* obj, Option_t* opt)
Float_t AverageCollisions()
TClass* Class()
virtual void Clear(Option_t* option)
virtual void Delete(Option_t* option)
virtual TObject* FindObject(Text_t* name)
virtual TObject* FindObject(TObject* obj)
virtual TClass* IsA()
void Rehash(Int_t newCapacity)
virtual TObject* Remove(TObject* obj)
virtual TObject* Remove(TObjLink* lnk)
virtual void ShowMembers(TMemberInspector& insp, char* parent)
virtual void Streamer(TBuffer& b)
protected:
THashTable* fTable Hashtable used for quick lookup of objects
THashList
THashList implements a hybrid collection class consisting of a
hash table and a list to store TObject's. The hash table is used for
quick access and lookup of objects while the list allows the objects
to be ordered. The hash value is calculated using the value returned
by the TObject's Hash() function. Each class inheriting from TObject
can override Hash() as it sees fit.
/*
*/
THashList(Int_t capacity, Int_t rehash)
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. If rehash=0 the table will
NOT automatically be rehashed. Use Rehash() for manual rehashing.
THashList(TObject *parent, Int_t capacity, Int_t rehash)
: TList(parent)
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. If rehash=0 the table will
NOT automatically be rehashed. Use Rehash() for manual rehashing.
~THashList()
Delete a hashlist. All objects will be removed from the list before the
list will be deleted.
void AddFirst(TObject *obj)
Add object at the beginning of the list.
void AddFirst(TObject *obj, Option_t *opt)
Add object at the beginning of the list and also store option.
Storing an option is useful when one wants to change the behaviour
of an object a little without having to create a complete new
copy of the object. This feature is used, for example, by the Draw()
method. It allows the same object to be drawn in different ways.
void AddLast(TObject *obj)
Add object at the end of the list.
void AddLast(TObject *obj, Option_t *opt)
Add object at the end of the list and also store option.
Storing an option is useful when one wants to change the behaviour
of an object a little without having to create a complete new
copy of the object. This feature is used, for example, by the Draw()
method. It allows the same object to be drawn in different ways.
void AddBefore(TObject *before, TObject *obj)
Insert object before object before in the list.
void AddBefore(TObjLink *before, TObject *obj)
Insert object before object before in the list.
void AddAfter(TObject *after, TObject *obj)
Insert object after object after in the list.
void AddAfter(TObjLink *after, TObject *obj)
Insert object after object after in the list.
void AddAt(TObject *obj, Int_t idx)
Insert object at location idx in the list.
Float_t 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().
void Clear(Option_t *option)
Remove all objects from the list. Does not delete the objects.
void Delete(Option_t *option)
Remove all objects from the list AND delete all heap based objects.
TObject* FindObject(const Text_t *name) const
Find object using its name. Uses the hash value returned by the
TString::Hash() after converting name to a TString.
TObject* FindObject(TObject *obj) const
Find object using its hash value (returned by its Hash() member).
void Rehash(Int_t newCapacity)
Rehash the hashlist. If the collision rate becomes too high (i.e.
the average size of the linked lists become too long) then lookup
efficiency decreases since relatively long lists have to be searched
every time. To improve performance rehash the hashtable. This resizes
the table to newCapacity slots and refills the table. Use
AverageCollisions() to check if you need to rehash.
TObject* Remove(TObject *obj)
Remove object from the list.
TObject* Remove(TObjLink *lnk)
Remove object via its objlink from the list.
Inline Functions
TClass* Class()
TClass* IsA()
void ShowMembers(TMemberInspector& insp, char* parent)
void Streamer(TBuffer& b)
Author: Fons Rademakers 10/08/95
Last update: 2.20/00 12/11/98 17.11.54 by Fons Rademakers
Copyright (c) 1995-1999, The ROOT System, All rights reserved. *
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