UMap(3U)						    InterViews Reference Manual 						  UMap(3U)

NAME

       UMap - maintains a mapping between two sets of pointers

SYNOPSIS

       #include <Unidraw/umap.h>

DESCRIPTION

       UMap  is an abstract class for objects that store an arbitrary number of pointer pairs and can search to find either member of a pair given
       the other.  A UMapElem object stores each pointer pair in the UMap.  UMapElem is an abstract class  that  defines  virtuals  for  returning
       either  member  of  the pair, referred to as the id and the tag.  Subclasses of UMapElem redefine these virtuals to return either member of
       the pair they store.

UMAPELEM PUBLIC OPERATIONS

       UMapElem()
	      The base class constructor does nothing by default.

       virtual void* id()
       virtual void* tag()
	      Return the id or the tag that the UMapElem stores.  Subclasses typically define two member variables that store  pair's  values  and
	      redefine these operations to return them.

UMAP PUBLIC OPERATIONS

       virtual ~UMap()
	      The destructor deletes all UMapElem objects in the UMap.

       int Count()
	      Return the number of mappings in the UMap, corresponding to the number of UMapElems that have been registered.

       void Clear()
	      Delete all the UMapElem mappings in the UMap without destroying the UMap.

UMAP PROTECTED OPERATIONS

       UMap() The base class constructor does nothing by default.

       void Register(UMapElem*)
       void Unregister(UMapElem*)
	      Register or remove a UMapElem from the UMap.

       int Index(UMapElem*)
       UMapElem* Elem(int index)
	      A  UMap  stores  its  UMapElem  in its _elems UArray protected member variable.  The Index operations returns the index of the given
	      UMapElem in the UArray, while Elem returns the UMapElem at a specified index.  These operations  simply  perform	the  corresponding
	      operations on the UArray.

       virtual UMapElem* FindId(void* id)
       virtual UMapElem* FindTag(void* tag)
	      FindId  searches	the  UMap for the UMapElem element containing the given id, while FindTag searches for the one with the given tag.
	      These operations perform linear searches by default, comparing their arguments against the values that the  UMapElems'  id  and  tag
	      operations  return.   The comparison is based on the pointer values; subclasses can redefine these operations to make more sophisti-
	      cated comparisons based on the id or tags actual type.  For example, if either the id is a string, then FindId  might  do  a  string
	      comparison to detect a match.

SEE ALSO

       UArray(3U)

Unidraw 							  4 October 1990							  UMap(3U)