-- File:	MoniTool_OptValue.cdl
-- Created:	Fri Dec 17 10:52:31 1999
-- Author:	Christian CAILLET
--		<cky@heliox.paris1.matra-dtv.fr>
---Copyright:	 Matra Datavision 1999


class OptValue  from MoniTool

    ---Purpose : This class allows two kinds of use
    --         
    --           As an object, a OptValue can be put in any operator or
    --           algorithm ... to use an Option of a Profile, by recording
    --           its value, hence avoiding to query the Profile eachtime
    --           
    --           This object brings a value which can be set as coming from a
    --           Profile, with a configuration name and for an Option name
    --           This value is evaluated then returned immediately
    --           
    --           As a class, it can be redefined to work on a dedicated
    --           Profile, provided by such or such specific way (as static
    --           context for instance)
    --           
    --           To change configuration, etc... can be done by querying and
    --           editing the Profile

uses AsciiString from TCollection, Transient,
     Profile from MoniTool

is

    Create (opt : CString = "") returns OptValue;
    ---Purpose : Creates an OptValue on a given Option
    --           This allows to use "shortcut" method to set the value
    --           
    --           WARNING : loading is not done at creation time. It must be
    --           done explicitly by call to Load
    --           
    --           The reason comes from C++ : the Profile being virtual, and
    --           intended to be redefined in sub-classes, must not be used in
    --           the constructor. A separate method, called on the object
    --           already created with its true type, must be called after

    	-- Methods to set an OptValue
    	-- Two kinds : basic methods (which require complete set of arguments)
    	--   and shortcuts (which allow to use pre-defined Profile and Option)

    	-- Basic Methods

    Clear (me : in out);
    ---Purpose : Clears the Value of the OptValue

    SetValue (me : in out; prof : Profile; opt : CString; fast : Boolean = Standard_True);
    ---Purpose : Sets the value as coming from the Profile, according to an
    --           Option name. Access as Fast or regular
    --           If no value is available, the former one remains : can be
    --             cleared by call to Clear

    	-- Context
    	-- It is defined by the Option name given when creating the OptValue,
    	--   and the Profile, provided by a specific virtual method : Prof

    Prof (me) returns Profile  is virtual;
    ---Purpose : Returns the Profile which can be used by Short Cut methods
    --           Defaults returns a Null Handle, can be redefined
    --           For instance, to return a static used as dictionary or context

    	-- Short Cuts
    	-- They suppose that Profile is provided and that Option name has been
    	--   given when creating

    Load (me : in out; fast : Boolean = Standard_True);
    ---Purpose : Sets the value from the Profile returned by method Prof,
    --           and Option Name given at creation time.
    --           FastValue by default, else Value
    --           
    --           Does not check if already loaded : reloads anyway
    --           IsLoaded allows to test

    	-- Returned Value

    IsLoaded (me) returns Boolean;
    ---Purpose : Says if the OptValue is already loaded (i.e. Value defined)

    Value (me; val : out Transient);
    ---Purpose : Returns the Value set by, either SetConf or SetValue
    --           Can be Null ... (if not set or not properly set)
    --           
    --           Returned as Argument, hence avoiding DownCast
    --  Warning : type is not controlled

    Delete (me:out) is virtual; 
    	---C++: alias "Standard_EXPORT virtual ~MoniTool_OptValue() { Delete(); }" 	    

fields

    theopt : AsciiString;
    theval : Transient;

end OptValue;