-- File:	EntityIterator.cdl
-- Created:	Mon Feb  3 14:08:35 1992
-- Author:	Christian CAILLET
--		<cky@phobox>
---Copyright:	 Matra Datavision 1992


class EntityIterator  from Interface

    ---Purpose : Defines an Iterator on Entities, complying with GraphTools
    --           needs. Allows considering of various criteria

uses Transient, HSequenceOfTransient from TColStd,
     IntVal, InterfaceModel

raises NoMoreObject, NoSuchObject

is

    Create returns EntityIterator;
    ---Purpose : Defines an empty iterator (see AddList & AddItem)

    Create  (list : HSequenceOfTransient)  returns EntityIterator;
    ---Purpose : Defines an iterator on a list, directly i.e. without copying it

    AddList (me : in out; list : HSequenceOfTransient);
    ---Purpose : Gets a list of entities and adds its to the iteration list

    AddItem (me : in out; anentity : any Transient);
    ---Purpose : Adds to the iteration list a defined entity

    GetOneItem (me : in out; anentity : any Transient) is static;
    ---Purpose : same as AddItem (kept for compatibility)

    Reset (me : in out) is protected;
    ---Purpose : Allows subclasses of EntityIterator to reevaluate an iteration

    SelectType (me : in out; atype : Type; keep : Boolean);
    ---Purpose : Selects entities with are Kind of a given type,  keep only
    --           them (is keep is True) or reject only them (if keep is False)


    NbEntities (me) returns Integer  is static;
    ---Purpose : Returns count of entities which will be iterated on
    --           Calls Start if not yet done

    NbTyped    (me; type : Type) returns Integer  is static;
    ---Purpose : Returns count of entities of a given type (kind of)

    Typed      (me; type : Type) returns EntityIterator;
    ---Purpose : Returns the list of entities of a given type (kind of)

    Start (me)  is virtual;
    ---Purpose : Allows re-iteration (useless for the first iteration)

    More (me) returns Boolean;
    ---Purpose : Says if there are other entities (vertices) to iterate
    --           the first time, calls Start

    Next (me) raises NoMoreObject;
    ---Purpose : Sets iteration to the next entity (vertex) to give

    Value (me) returns any Transient  raises NoSuchObject;
    ---Purpose : Returns the current Entity iterated, to be used by Interface
    --           tools or by GraphTools (where Entity is a Vertex)
    ---C++ : return const &

    Content (me) returns HSequenceOfTransient;
    ---Purpose : Returns the content of the Iterator, accessed through a Handle
    --           to be used by a frontal-engine logic
    --           Returns an empty Sequence if the Iterator is empty
    --           Calls Start if not yet done

    Destroy (me : in out) is virtual;
    ---Purpose : Clears data of iteration
    ---C++: alias "Standard_EXPORT virtual ~Interface_EntityIterator() { Destroy();}"
    
fields

    thecurr : IntVal;
    thelist : HSequenceOfTransient;

end EntityIterator;