TList

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 R__FOR_EACH macro:                                   
         GetListOfPrimitives()->R__FOR_EACH(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.

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, 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(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(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 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).

TObject * FindObject(const char *name)

 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)

 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.

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).

TList

class TList : public TSeqCollection

Data Members

Class Description