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

---Version:	0.0
---History:	Version	Date		Purpose
--		0.0	Oct  1 1997	Creation


class Transaction from TDF

	---Purpose: This class offers services to open, commit or
	--          abort a transaction in a more secure way than
	--          using Data from TDF. If you forget to close a
	--          transaction, it will be automaticaly aborted at
	--          the destruction of this object, at the closure of
	--          its scope.
	--          
	--          In case of catching errors, the effect will be the
	--          same: aborting transactions until the good current
	--          one.

uses

    Data  from TDF,
    Delta from TDF,
    AsciiString from TCollection

raises

    DomainError, NullObject from Standard

is

    Create(aName : AsciiString from TCollection = "")
    	returns Transaction from TDF;
	---Purpose: Creates an empty transaction context, unable to be
	--          opened.

    Create(aTrans : Transaction from TDF)
    	returns Transaction from TDF
    	is private;
	---Purpose: Private to avoid copy.

    Create(aDF : Data from TDF;
    	   aName : AsciiString from TCollection = "")
    	returns Transaction from TDF;
	---Purpose: Creates a transaction context on <aDF>, ready to
	--          be opened.

    Initialize(me : in out; aDF : Data from TDF);
	---Purpose: Aborts all the transactions on <myDF> and sets
	--          <aDF> to build a transaction context on <aDF>,
	--          ready to be opened.

    Open(me : in out)
    	returns Integer from Standard
    	raises DomainError, NullObject from Standard;
	---Purpose: If not yet done, opens a new transaction on
	--          <myDF>. Returns the index of the just opened
	--          transaction.
	--          
	--          It raises DomainError if the transaction is
	--          already open, and NullObject if there is no
	--          current Data framework.

    Commit(me : in out;
    	   withDelta : Boolean from Standard = Standard_False)
    	returns Delta from TDF;
	---Purpose: Commits the transactions until AND including the
	--          current opened one.

    Abort(me : in out);
	---Purpose: Aborts the transactions until AND including the
	--          current opened one.
	--          
	---C++: alias ~

    Data(me) returns Data from TDF;
	---Purpose: Returns the Data from TDF.
	--          
	---C++: inline

    Transaction(me) returns Integer from Standard;
	---Purpose: Returns the number of the transaction opened by <me>.
	--          
	---C++: inline

    Name(me) returns AsciiString from TCollection;
	---Purpose: Returns the transaction name.
	--          
	---C++: return const &

    IsOpen(me)
    	returns Boolean from Standard;
	---Purpose: Returns true if the transaction is open.
	--          
	---C++: inline


fields

    myDF               : Data from TDF;
    myUntilTransaction : Integer from Standard;
    myName             : AsciiString from TCollection;

end Transaction;