TList


class description - source file - inheritance tree

class TList : public TSeqCollection


    protected:
virtual void DeleteLink(TObjLink* lnk) TObjLink** DoSort(TObjLink** head, Int_t n) TObjLink* FindLink(const TObject* obj, Int_t& idx) const TObjLink* LinkAt(Int_t idx) const Bool_t LnkCompare(TObjLink* l1, TObjLink* l2) virtual TObjLink* NewLink(TObject* obj, TObjLink* prev = 0) virtual TObjLink* NewOptLink(TObject* obj, Option_t* opt, TObjLink* prev = 0) public:
TList TList() TList TList(TObject*) virtual void ~TList() virtual void Add(TObject* obj) virtual void Add(TObject* obj, Option_t* opt) virtual void AddAfter(TObjLink* after, TObject* obj) virtual void AddAfter(TObject* after, TObject* obj) virtual void AddAt(TObject* obj, Int_t idx) virtual void AddBefore(TObjLink* before, TObject* obj) virtual void AddBefore(TObject* before, TObject* obj) virtual void AddFirst(TObject* obj) virtual void AddFirst(TObject* obj, Option_t* opt) virtual void AddLast(TObject* obj, Option_t* opt) virtual void AddLast(TObject* obj) virtual TObject* After(TObject* obj) const virtual TObject* At(Int_t idx) const virtual TObject* Before(TObject* obj) const static TClass* Class() virtual void Clear(Option_t* option) virtual void Delete(Option_t* option) virtual TObject* FindObject(const TObject* obj) const virtual TObject* FindObject(const char* name) const virtual TObject* First() const virtual TObjLink* FirstLink() const virtual TClass* IsA() const Bool_t IsAscending() virtual TObject* Last() const virtual TObjLink* LastLink() const virtual TIterator* MakeIterator(Bool_t dir = kIterForward) const virtual TObject* Remove(TObject* obj) virtual TObject* Remove(TObjLink* lnk) virtual void ShowMembers(TMemberInspector& insp, char* parent) virtual void Sort(Bool_t order = kSortAscending) virtual void Streamer(TBuffer& b) void StreamerNVirtual(TBuffer& b)

Data Members

protected:
TObjLink* fFirst ! pointer to first entry in linked list TObjLink* fLast ! pointer to last entry in linked list TObjLink* fCache ! cache to speedup sequential calling of Before() and After() functions Bool_t fAscending ! sorting order (when calling Sort() or for TSortedList) public:


See also

THashList, TQConnection, TSortedList

Class Description

                                                                      
 TList                                                                
                                                                      
 A doubly linked list. All classes inheriting from TObject can be     
 inserted in a TList. Before being inserted into the list the object  
 pointer is wrapped in a TObjLink object which contains, besides      
 the object pointer also a previous and next pointer.                 
                                                                      
 There are basically four ways to iterate over a TList (in order      
 of preference, if not forced by other constraints):                  
    1) Using the ForEach macro:                                       
         GetListOfPrimitives()->ForEach(TObject,Paint)(option);       
                                                                      
    2) Using the TList iterator TListIter (via the wrapper class      
       TIter):                                                        
         TIter next(GetListOfPrimitives());                           
         while (TObject *obj = next())                                
            obj->Draw(next.GetOption());                              
                                                                      
    3) Using the TObjLink list entries (that wrap the TObject*):      
         TObjLink *lnk = GetListOfPrimitives()->FirstLink();          
         while (lnk) {                                                
            lnk->GetObject()->Draw(lnk->GetOption());                 
            lnk = lnk->Next();                                        
         }                                                            
                                                                      
    4) Using the TList's After() and Before() member functions:       
         TFree *idcur = this;                                         
         while (idcur) {                                              
            ...                                                       
            ...                                                       
            idcur = (TFree*)GetListOfFree()->After(idcur);            
         }                                                            
                                                                      
   Methods 2, 3 and 4 can also easily iterate backwards using either  
   a backward TIter (using argument kIterBackward) or by using        
   LastLink() and lnk->Prev() or by using the Before() member.        
                             
                                                                      


~TList()
 Delete the list. Objects are not deleted unless the TList is the
 owner (set via SetOwner()).

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 the specified ObjLink object. If before = 0 then add
 to the head of the list. An ObjLink can be obtained by looping over a list
 using the above describe iterator method 3.

void AddAfter(TObject *after, TObject *obj)
 Insert object after object after in the list.

void AddAfter(TObjLink *after, TObject *obj)
 Insert object after the specified ObjLink object. If after = 0 then add
 to the tail of the list. An ObjLink can be obtained by looping over a list
 using the above describe iterator method 3.

void AddAt(TObject *obj, Int_t idx)
 Insert object at position idx in the list.

TObject* After(TObject *obj) const
 Returns the object after object obj. Returns 0 if obj is last in list.

TObject* At(Int_t idx) const
 Returns the object at position idx. Returns 0 if idx is out of range.

TObject* Before(TObject *obj) const
 Returns the object before object obj. Returns 0 if obj is first in list.

void Clear(Option_t *option)
 Remove all objects from the list. Does not delete the objects
 unless the TList is the owner (set via SetOwner()) and option
 "nodelete" is not set.
 If option="nodelete" then don't delete any heap objects that were
 marked with the kCanDelete bit, otherwise these objects will be
 deleted (this option is used by THashTable::Clear()).

void Delete(Option_t *option)
 Remove all objects from the list AND delete all heap based objects.
 If option="slow" then keep list consistent during delete. This allows
 recursive list operations during the delete (e.g. during the dtor
 of an object in this list one can still access the list to search for
 other not yet deleted objects).

void DeleteLink(TObjLink *lnk)
 Delete a TObjLink object.

TObject* FindObject(const char *name) const
 Find an object in this list using its name. Requires a sequential
 scan till the object has been found. Returns 0 if object with specified
 name is not found. This method overrides the generic FindObject()
 of TCollection for efficiency reasons.

TObject* FindObject(const TObject *obj) const
 Find an object in this list using the object's IsEqual()
 member function. Requires a sequential scan till the object has
 been found. Returns 0 if object is not found.
 This method overrides the generic FindObject() of TCollection for
 efficiency reasons.

TObjLink* FindLink(const TObject *obj, Int_t &idx) const
 Returns the TObjLink object that contains object obj. In idx it returns
 the position of the object in the list.

TObject* First() const
 Return the first object in the list. Returns 0 when list is empty.

TObject* Last() const
 Return the last object in the list. Returns 0 when list is empty.

TObjLink* LinkAt(Int_t idx) const
 Return the TObjLink object at index idx.

TIterator* MakeIterator(Bool_t dir) const
 Return a list iterator.

TObjLink* NewLink(TObject *obj, TObjLink *prev)
 Return a new TObjLink.

TObjLink* NewOptLink(TObject *obj, Option_t *opt, TObjLink *prev)
 Return a new TObjOptLink (a TObjLink that also stores the option).

TObject* Remove(TObject *obj)
 Remove object from the list.

TObject* Remove(TObjLink *lnk)
 Remove object link (and therefore the object it contains)
 from the list.

void Sort(Bool_t order)
 Sort linked list. Real sorting is done in private function DoSort().
 The list can only be sorted when is contains objects of a sortable
 class.

Bool_t LnkCompare(TObjLink *l1, TObjLink *l2)
 Compares the objects stored in the TObjLink objects.
 Depending on the flag IsAscending() the function returns
 true if the object in l1 <= l2 (ascending) or l2 <= l1 (descending).

TObjLink** DoSort(TObjLink **head, Int_t n)
 Sort linked list.

void Streamer(TBuffer &b)
 Stream all objects in the collection to or from the I/O buffer.



Inline Functions


              TList TList()
              TList TList(TObject*)
               void Add(TObject* obj)
               void Add(TObject* obj, Option_t* opt)
          TObjLink* FirstLink() const
          TObjLink* LastLink() const
             Bool_t IsAscending()
            TClass* Class()
            TClass* IsA() const
               void ShowMembers(TMemberInspector& insp, char* parent)
               void StreamerNVirtual(TBuffer& b)


Author: Fons Rademakers 10/08/95
Last update: root/cont:$Name: $:$Id: TList.cxx,v 1.8 2001/03/07 11:51:34 rdm Exp $
Copyright (C) 1995-2000, Rene Brun and Fons Rademakers. *


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