-- File:	GraphContent.cdl
-- Created:	Wed Sep 23 10:23:20 1992
-- Author:	Christian CAILLET
--		<cky@phobox>
---Copyright:	 Matra Datavision 1992


class GraphContent  from Interface  inherits EntityIterator

    	---Purpose : Defines general form for classes of graph algorithms on
    	--           Interfaces, this form is that of EntityIterator
    	--           Each sub-class fills it according to its own algorithm
    	--           This also allows to combine any graph result to others,
    	--           all being given under one unique form

uses Transient, Graph

is

    Create returns GraphContent;
    ---Purpose : Creates an empty GraphContent, ready to be filled

    Create (agraph : Graph) returns GraphContent;
    ---Purpose : Creates with all entities designated by a Graph

    Create (agraph : Graph; stat : Integer) returns GraphContent;
    ---Purpose : Creates with entities having specific Status value in a Graph

    Create (agraph : Graph; ent : Transient) returns GraphContent;
    ---Purpose : Creates an Iterator with Shared entities of an entity
    --           (equivalente to EntityIterator but with a Graph) 

    GetFromGraph (me : in out; agraph : Graph);
    ---Purpose : Gets all Entities designated by a Graph (once created), adds
    --           them to those already recorded

    GetFromGraph (me : in out; agraph : Graph; stat : Integer);
    ---Purpose : Gets entities from a graph which have a specific Status value
    --           (one created), adds them to those already recorded

    Result (me : in out) returns EntityIterator;
    ---Purpose : Returns Result under the exact form of an EntityIterator :
    --           Can be used when EntityIterator itself is required (as a
    --           returned value for instance), whitout way for a sub-class

    	-- --    Evaluation - Iteration    -- --
    	--   Made by Start-More-Next-Value  inherited from EntityIterator
    	--   Start is redefined to call Evaluate moreover
    	--   Default for Evaluate is given as doing nothing

--    Start (me : in out)  is redefined;
    Begin (me : in out);
    ---Purpose : Does the Evaluation before starting the iteration itself
    --           (in out)

    Evaluate (me : in out)  is virtual;
    ---Purpose : Evaluates list of Entities to be iterated. Called by Start
    --           Default is set to doing nothing : intended to be redefined
    --           by each sub-class

end GraphContent;