-- File:	Interface_ReaderModule.cdl
-- Created:	Thu Feb  4 18:06:48 1993
-- Author:	Christian CAILLET
--		<cky@phobox>
---Copyright:	 Matra Datavision 1993


deferred class ReaderModule  from Interface  inherits TShared

    ---Purpose : Defines unitary operations required to read an Entity from a
    --           File (see FileReaderData, FileReaderTool), under control of
    --           a FileReaderTool. The initial creation is performed by a
    --           GeneralModule (set in GeneralLib). Then, which remains is
    --           Loading data from the FileReaderData to the Entity
    --           
    --           To work, a GeneralModule has formerly recognized the Type read
    --           from FileReaderData as a positive Case Number, then the
    --           ReaderModule reads it according to this Case Number

uses Transient, FileReaderData, Check

raises DomainError

is

    CaseNum (me; data : FileReaderData; num : Integer) returns Integer
    	is deferred;
    ---Purpose : Translates the type of record <num> in <data> to a positive
    --           Case Number. If Recognition fails, must return 0

    Read (me; casenum : Integer; data : FileReaderData; num : Integer;
    	  ach : in out Check; ent : mutable Transient)
    ---Purpose : Performs the effective loading from <data>, record <num>,
    --           to the Entity <ent> formerly created
    --           In case of Error or Warning, fills <ach> with messages
    --           Remark that the Case Number comes from translating a record
    	  raises DomainError  is deferred;
    --           Can raise any exception, while it is preferable to prevent
    --           them and fill the Check

    NewRead (me; casenum : Integer; data : FileReaderData; num : Integer;
    	  ach : in out Check; ent : out mutable Transient) returns Boolean
    ---Purpose : Specific operator (create+read) defaulted to do nothing.
    --           It can be redefined when it is not possible to work in two
    --           steps (NewVoid then Read). This occurs when no default
    --           constructor is defined : hence the result <ent> must be
    --           created with an effective definition from the reader.
    --           Remark : if NewRead is defined, Copy has nothing to do.
    --           
    --           Returns True if it has produced something, false else.
    --           If nothing was produced, <ach> should be filled : it will be
    --           treated as "Unrecognized case" by reader tool.
    	  raises DomainError  is virtual;
    --           Can raise any exception, while it is preferable to prevent
    --           them and fill the Check

end ReaderModule;