Collection of Tools & Utilities/Collection of Tools and Utilities.iso/ada/bd3.zip/BD3.ADA

Text File | 1989-03-13 | 20KB | 541 lines

package BANK is
--------------------------------------------------------------------------
--| BEGIN PROLOGUE
--| DESCRIPTION            : BANK defines a bank, the TELLER objects
--|                        : within it, and the procedure PRINT_REPORT
--|                        : (which reports on the status of the BANK).
--|                        :
--|                        : BANK is an abstract state machine, defining
--|                        : a BANK object which contains TELLER objects.
--|                        :
--| REQUIREMENTS SUPPORTED : Bank Demonstration Program to show
--|                        : object-oriented design and tasking
--|                        : with Ada
--|                        :
--| LIMITATIONS            : None
--| AUTHOR(S)              : Richard Conn (RLC)
--| CHANGE LOG             : 1/16/89  RLC  Initial Design and Code
--| CHANGE LOG             : 2/25/89  RLC  Final Review Prior to Release
--| REMARKS                : None
--| PORTABILITY ISSUES     : None
--| END PROLOGUE
--------------------------------------------------------------------------

    -- TRANSACTION requested of a TELLER
    type TRANSACTION  is (ADD_NEW_CUSTOMER,
                          GET_BALANCE,
                          MAKE_DEPOSIT,
                          MAKE_WITHDRAWAL);

    -- Unit of currency
    type DOLLAR       is new FLOAT;

    -- Identification of a CUSTOMER
    type CUSTOMER_ID  is new NATURAL range 1 .. NATURAL'LAST;

    -- Index of and Number of TELLER objects within the bank
    type TELLER_INDEX is new NATURAL range 1 .. 4;

    -- A TELLER_PERSON is an object to which a CUSTOMER may make a REQUEST
    -- The BANK tells the TELLER_PERSON to START_WORK, giving the
    -- TELLER_PERSON its TELLER_NUMBER
    task type TELLER_PERSON is
    entry REQUEST(ID     : in out CUSTOMER_ID;
              KIND   : in TRANSACTION;
              AMOUNT : in out DOLLAR);
    end TELLER_PERSON;
    -- These are the TELLER objects available at the bank
    TELLER : array(TELLER_INDEX) of TELLER_PERSON;

    -- PRINT_REPORT gives the transaction log of all the bank
    -- customers
    procedure PRINT_REPORT;

    -- STOP_WORK terminates all TELLER tasks
    procedure STOP_WORK;
end BANK;
--
with CONSOLE;
package body BANK is
--------------------------------------------------------------------------
--| BEGIN PROLOGUE
--| DESCRIPTION            : Package Body BANK implements the TELLER
--|                        : tasks and the PRINT_REPORT procedure.
--|                        : CUSTOMER data is maintained within the
--|                        : BANK as a linked list.
--|                        :
--| REQUIREMENTS SUPPORTED : Bank Demonstration Program to show
--|                        : object-oriented design and tasking
--|                        : with Ada
--|                        :
--| LIMITATIONS            : None
--| AUTHOR(S)              : Richard Conn (RLC)
--| CHANGE LOG             : 1/16/89  RLC  Initial Design and Code
--| CHANGE LOG             : 2/25/89  RLC  Final Review Prior to Release
--| REMARKS                : None
--| PORTABILITY ISSUES     : Uses CONSOLE (TEXT_IO), so is very portable;
--|                        : no known portability problems.
--| END PROLOGUE
--------------------------------------------------------------------------

    -- Identifier of next customer
    NEXT_ID                  : CUSTOMER_ID           := CUSTOMER_ID'FIRST;

    -- Linked list of customer data
    type CUSTOMER_DATA;
    type CUSTOMER_DATA_POINTER is access CUSTOMER_DATA;
    type CUSTOMER_DATA is record
    ID                  : CUSTOMER_ID;
    BALANCE             : DOLLAR                := 0.0;
    TRANSACTION_COUNT   : NATURAL               := 0;
    ATTEMPTED_OVERDRAWS : NATURAL               := 0;
    NEXT                : CUSTOMER_DATA_POINTER := null;
    end record;

    -- Count of number of transactions for each TELLER object
    TELLER_TRANSACTION_COUNT : array(TELLER_INDEX) of NATURAL
      := (others => 0);

    -- Pointers to first and last customer data entries
    FIRST_CUSTOMER           : CUSTOMER_DATA_POINTER := null;
    LAST_CUSTOMER            : CUSTOMER_DATA_POINTER := null;

--
-- package body BANK
    -- Print a report of the status of the BANK
    procedure PRINT_REPORT is
    CURRENT_CUSTOMER : CUSTOMER_DATA_POINTER;
    begin

        -- Check for any customers and issue an error message if none
    if NEXT_ID = CUSTOMER_ID'FIRST then
        CONSOLE.WRITE("The bank doesn't have any customers");
        CONSOLE.WRITE(CONSOLE.NEW_LINE);

        -- Generate report
    else

            -- Customer balance, transaction count, attempted overdraw
            -- count report
        CONSOLE.WRITE("**** BANK STATUS REPORT ****");
        CONSOLE.WRITE(CONSOLE.NEW_LINE);
        CONSOLE.WRITE(
              "Customer      Balance  Transactions  Attempted_Overdraws");
        CONSOLE.WRITE(CONSOLE.NEW_LINE);
        CURRENT_CUSTOMER := FIRST_CUSTOMER;
        while CURRENT_CUSTOMER /= null loop
        CONSOLE.WRITE(INTEGER(CURRENT_CUSTOMER.ID), 5);
        CONSOLE.WRITE("     ");
        CONSOLE.WRITE(FLOAT(CURRENT_CUSTOMER.BALANCE), 8, 2);
        CONSOLE.WRITE("      ");
        CONSOLE.WRITE(INTEGER(CURRENT_CUSTOMER.TRANSACTION_COUNT), 8);
        CONSOLE.WRITE("             ");
        CONSOLE.WRITE(INTEGER(CURRENT_CUSTOMER.ATTEMPTED_OVERDRAWS),
          8);
        CONSOLE.WRITE(CONSOLE.NEW_LINE);
        CURRENT_CUSTOMER := CURRENT_CUSTOMER.NEXT;
        end loop;
        CONSOLE.WRITE(CONSOLE.NEW_LINE);

            -- Teller transaction count report
        CONSOLE.WRITE("Teller           : ");
        for I in TELLER_INDEX loop
        CONSOLE.WRITE(INTEGER(I), 8);
        end loop;
        CONSOLE.WRITE(CONSOLE.NEW_LINE);
        CONSOLE.WRITE("Transaction_Count: ");
        for I in TELLER_INDEX loop
        CONSOLE.WRITE(INTEGER(TELLER_TRANSACTION_COUNT(I)), 8);
        end loop;
        CONSOLE.WRITE(CONSOLE.NEW_LINE);

    end if;
    end PRINT_REPORT;

    -- Terminate all TELLER tasks
    procedure STOP_WORK is
    begin
    for I in TELLER_INDEX loop
        abort TELLER(I);
    end loop;
    end STOP_WORK;
--
-- package body BANK

    -- FIND_CUSTOMER is used to find a CUSTOMER_DATA record
    -- based on a CUSTOMER_ID number
    function FIND_CUSTOMER(ID : in CUSTOMER_ID)
                return CUSTOMER_DATA_POINTER is
    CURRENT_CUSTOMER : CUSTOMER_DATA_POINTER;
    begin
    CURRENT_CUSTOMER := FIRST_CUSTOMER;
    while CURRENT_CUSTOMER /= null loop
        exit when CURRENT_CUSTOMER.ID = ID;
        CURRENT_CUSTOMER := CURRENT_CUSTOMER.NEXT;
    end loop;
    return CURRENT_CUSTOMER;
    end FIND_CUSTOMER;


--
-- package body BANK

    task TELLER_ASSIGNER is
    -- This task assigns an ID number to a teller.
    -- TELLER_ASSIGNER is called by the TELLER_PERSON task when the
    -- TELLER_PERSON task first starts up.
    entry GET_TELLER_ID(ID : out TELLER_INDEX);
    end TELLER_ASSIGNER;

    task body TELLER_ASSIGNER is
    NEXT_TELLER_ID : TELLER_INDEX := TELLER_INDEX'FIRST;
    begin
    loop
        accept GET_TELLER_ID(ID : out TELLER_INDEX) do
        ID := NEXT_TELLER_ID;
        if NEXT_TELLER_ID /= TELLER_INDEX'LAST then
            NEXT_TELLER_ID := NEXT_TELLER_ID + 1;
        end if;
        end GET_TELLER_ID;
    end loop;
    end TELLER_ASSIGNER;

--
-- package body BANK

    -- Implementation of a TELLER task
    task body TELLER_PERSON is

    THIS_CUSTOMER : CUSTOMER_DATA_POINTER;
    MY_NUMBER     : TELLER_INDEX;

    begin

        -- TELLER gets his ID number
    TELLER_ASSIGNER.GET_TELLER_ID(MY_NUMBER);

        -- TELLER loops on REQUESTs from CUSTOMERs
    loop
        accept REQUEST(ID     : in out CUSTOMER_ID;
               KIND   : in TRANSACTION;
               AMOUNT : in out DOLLAR) do

                -- Increment teller's transaction count
        TELLER_TRANSACTION_COUNT(MY_