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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;