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-- F393B00.A   
 -- Alert_Foundation
 --
--                             Grant of Unlimited Rights
--
--     Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
--     F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained 
--     unlimited rights in the software and documentation contained herein.
--     Unlimited rights are defined in DFAR 252.227-7013(a)(19).  By making 
--     this public release, the Government intends to confer upon all 
--     recipients unlimited rights  equal to those held by the Government.  
--     These rights include rights to use, duplicate, release or disclose the 
--     released technical data and computer software in whole or in part, in 
--     any manner and for any purpose whatsoever, and to have or permit others 
--     to do so.
--
--                                    DISCLAIMER
--
--     ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
--     DISCLOSED ARE AS IS.  THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED 
--     WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
--     SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE 
--     OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
--     PARTICULAR PURPOSE OF SAID MATERIAL.
--*
 --
 -- FOUNDATION DESCRIPTION:
 --      This package declares three abstract types for use in C660 series 
 --      tests, Alert, Special_Alert, and Private_Alert.
 --      It models (in miniature) an application situation in which an 
 --      abstraction is defined in terms of structure (record and operations 
 --      on the record) but not in terms of content (record is null).  It 
 --      also models a situation in which an abstraction includes some 
 --      specific, implementation dependent, information.
 --
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--
 --!
 
 package F393B00 is
    type Alert is abstract tagged null record;  -- abstract type
                                                -- see procedure Handle below
 
    procedure Handle (A : in out Alert) is abstract;
                                                -- abstract procedure, 
                                                -- explicitly declared
 
 
    type Private_Alert is abstract tagged private;
 
    procedure Handle (PA : in out Private_Alert) is abstract;
                                                -- ensures that Private_Alert
                                                -- is visibly abstract
 
 
    type Status_Kind is (Practice, Real, Dont_Care);
    type Urgency_Kind is (Low, Medium, High);
 
    type Practice_Alert is new Alert with record
      Status : Status_Kind := Dont_Care;
      Urgency : Urgency_Kind := Low;
    end record;
 
    procedure Handle (PA : in out Practice_Alert);
                                                -- overrides inherited Handle
 
 
 
    type Device is (Teletype, Console, Big_Screen);
 
    type Special_Alert (Age : Integer) is 
      abstract new Practice_Alert with record
        Display : Device;
      end record;
 
    procedure Handle (SA : in out Special_Alert) is abstract; 
                                                -- overrides inherited Handle
 
 private
    subtype Implementation_Detail is Integer range 1..10;
 
    type Private_Alert is abstract tagged record
      Private_Field : Implementation_Detail := 1;
    end record;
 
  
 end F393B00;
 
 --=======================================================================--
 
 package body F393B00 is
 
      procedure Handle (PA : in out Practice_Alert) is
        begin
          PA.Status := Real;
          PA.Urgency := Medium;
        end Handle;
 
 end F393B00;