-- File:	TDocStd_XLinkRoot.cdl
--      	------------------------
-- Author:	DAUTRY Philippe
--		<fid@fox.paris1.matra-dtv.fr>
---Copyright:	 MATRA DATAVISION 1997

---Version:	0.0
---History:	Version	Date		Purpose
--		0.0	Aug 27 1997	Creation


private class XLinkRoot from TDocStd inherits Attribute from TDF

	---Purpose: This attribute is the root of all external
	--          references contained in a Data from TDF. Only one
	--          instance of this class is added to the TDF_Data
	--          root label. Starting from this attribute all the
	--          Reference are linked together, to be found
	--          easely.

uses

    GUID from Standard,
    Data            from TDF,
    RelocationTable from TDF,
    XLink    from TDocStd,
    XLinkPtr from TDocStd

-- raises

is

    -- CLASS methods.
    -- --------------

    GetID(myclass) returns GUID from Standard;
	---Purpose: Returns the ID: 2a96b61d-ec8b-11d0-bee7-080009dc3333
	--          
    	---C++: return const &
    
    Set(myclass; aDF : Data from TDF)
    	returns XLinkRoot from TDocStd;
	---Purpose: Sets an empty XLinkRoot to Root or gets the
	--          existing one. Only one attribute per TDF_Data.

    Insert(myclass; anXLinkPtr : XLinkPtr from TDocStd);
	---Purpose: Inserts <anXLinkPtr> at the beginning of the XLink chain.

    Remove(myclass; anXLinkPtr : XLinkPtr from TDocStd);
	---Purpose: Removes <anXLinkPtr> from the XLink chain, if it exists.

    -- Basic methods.
    -- --------------

    Create
    	returns mutable XLinkRoot from TDocStd
    	is private;
	---Purpose: Initializes fields.

    -- Information access.
    -- -------------------

    ID(me) returns GUID from Standard
    	is redefined static;
	---Purpose: Returns the ID of the attribute.
	--          
	---C++: return const &             	
  
    BackupCopy(me) returns mutable Attribute from TDF
    	is redefined static;
	---Purpose: Returns a null handle.

    Restore(me: mutable;
    	    anAttribute : Attribute from TDF)
    	is redefined static;
	---Purpose: Does nothing.


    First(me : mutable; anXLinkPtr : XLinkPtr from TDocStd)
    	is private;
	---Purpose: Sets the field <myFirst> with <anXLinkPtr>.
	--          
	---C++: inline

    First(me)
    	returns XLinkPtr from TDocStd
    	is private;
	---Purpose: Returns the contents of the field <myFirst>.
	--          
	---C++: inline


    -- Copy use methods
    -- ----------------

    NewEmpty(me)
    	returns mutable Attribute from TDF
    	is redefined static;
	---Purpose: Returns a null handle.

    Paste(me;
    	  intoAttribute    : mutable Attribute from TDF;
	  aRelocationTable : mutable RelocationTable from TDF)
    	is redefined static;
	---Purpose: Does nothing.

    -- Miscelleaneous
    -- --------------


    Dump(me; anOS : in out OStream from Standard)
    	returns OStream from Standard
    	is redefined static;
	---Purpose: Dumps the attribute on <aStream>.
    	---C++ : return &


fields

    myFirst : XLinkPtr from TDocStd;

friends

    class XLinkIterator from TDocStd

end XLinkRoot;