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File List | 1989-03-12 | 21.4 KB | 541 lines

1 package BANK is 2 ------------------------------------------------------------------------ 3 --| BEGIN PROLOGUE 4 --| DESCRIPTION : BANK defines a bank, the TELLER objects 5 --| : within it, and the procedure PRINT_REPORT 6 --| : (which reports on the status of the BANK). 7 --| : 8 --| : BANK is an abstract state machine, defining 9 --| : a BANK object which contains TELLER objects. 10 --| : 11 --| REQUIREMENTS SUPPORTED : Bank Demonstration Program to show 12 --| : object-oriented design and tasking 13 --| : with Ada 14 --| : 15 --| LIMITATIONS : None 16 --| AUTHOR(S) : Richard Conn (RLC) 17 --| CHANGE LOG : 1/16/89 RLC Initial Design and Code 18 --| CHANGE LOG : 2/25/89 RLC Final Review Prior to Release 19 --| REMARKS : None 20 --| PORTABILITY ISSUES : None 21 --| END PROLOGUE 22 ------------------------------------------------------------------------ 23 24 -- TRANSACTION requested of a TELLER 25 type TRANSACTION is (ADD_NEW_CUSTOMER, 26 GET_BALANCE, 27 MAKE_DEPOSIT, 28 MAKE_WITHDRAWAL); 29 30 -- Unit of currency 31 type DOLLAR is new FLOAT; 32 33 -- Identification of a CUSTOMER 34 type CUSTOMER_ID is new NATURAL range 1 .. NATURAL'LAST; 35 36 -- Index of and Number of TELLER objects within the bank 37 type TELLER_INDEX is new NATURAL range 1 .. 4; 38 39 -- A TELLER_PERSON is an object to which a CUSTOMER may make a REQUEST 40 -- The BANK tells the TELLER_PERSON to START_WORK, giving the 41 -- TELLER_PERSON its TELLER_NUMBER 42 task type TELLER_PERSON is 43 entry REQUEST(ID : in out CUSTOMER_ID; 44 KIND : in TRANSACTION; 45 AMOUNT : in out DOLLAR); 46 end TELLER_PERSON; 47 -- These are the TELLER objects available at the bank 48 TELLER : array(TELLER_INDEX) of TELLER_PERSON; 49 50 -- PRINT_REPORT gives the transaction log of all the bank 51 -- customers 52 procedure PRINT_REPORT; 53 54 -- STOP_WORK terminates all TELLER tasks 55 procedure STOP_WORK; 56 end BANK; 57 -- 58 with CONSOLE; 59 package body BANK is 60 ------------------------------------------------------------------------ 61 --| BEGIN PROLOGUE 62 --| DESCRIPTION : Package Body BANK implements the TELLER 63 --| : tasks and the PRINT_REPORT procedure. 64 --| : CUSTOMER data is maintained within the 65 --| : BANK as a linked list. 66 --| : 67 --| REQUIREMENTS SUPPORTED : Bank Demonstration Program to show 68 --| : object-oriented design and tasking 69 --| : with Ada 70 --| : 71 --| LIMITATIONS : None 72 --| AUTHOR(S) : Richard Conn (RLC) 73 --| CHANGE LOG : 1/16/89 RLC Initial Design and Code 74 --| CHANGE LOG : 2/25/89 RLC Final Review Prior to Release 75 --| REMARKS : None 76 --| PORTABILITY ISSUES : Uses CONSOLE (TEXT_IO), so is very portable; 77 --| : no known portability problems. 78 --| END PROLOGUE 79 ------------------------------------------------------------------------ 80 81 -- Identifier of next customer 82 NEXT_ID : CUSTOMER_ID := CUSTOMER_ID'FIRST; 83 84 -- Linked list of customer data 85 type CUSTOMER_DATA; 86 type CUSTOMER_DATA_POINTER is access CUSTOMER_DATA; 87 type CUSTOMER_DATA is record 88 ID : CUSTOMER_ID; 89 BALANCE : DOLLAR := 0.0; 90 TRANSACTION_COUNT : NATURAL := 0; 91 ATTEMPTED_OVERDRAWS : NATURAL := 0; 92 NEXT : CUSTOMER_DATA_POINTER := null; 93 end record; 94 95 -- Count of number of transactions for each TELLER object 96 TELLER_TRANSACTION_COUNT : array(TELLER_INDEX) of NATURAL 97 := (others => 0); 98 99 -- Pointers to first and last customer data entries 100 FIRST_CUSTOMER : CUSTOMER_DATA_POINTER := null; 101 LAST_CUSTOMER : CUSTOMER_DATA_POINTER := null; 102 103 -- 104 -- package body BANK 105 -- Print a report of the status of the BANK 106 procedure PRINT_REPORT is 107 CURRENT_CUSTOMER : CUSTOMER_DATA_POINTER; 108 begin 109 110 -- Check for any customers and issue an error message if none 111 if NEXT_ID = CUSTOMER_ID'FIRST then 112 CONSOLE.WRITE("The bank doesn't have any customers"); 113 CONSOLE.WRITE(CONSOLE.NEW_LINE); 114 115 -- Generate report 116 else 117 118 -- Customer balance, transaction count, attempted overdraw 119 -- count report 120 CONSOLE.WRITE("**** BANK STATUS REPORT ****"); 121 CONSOLE.WRITE(CONSOLE.NEW_LINE); 122 CONSOLE.WRITE( 123 "Customer Balance Transactions Attempted_Overdraws"); 124 CONSOLE.WRITE(CONSOLE.NEW_LINE); 125 CURRENT_CUSTOMER := FIRST_CUSTOMER; 126 while CURRENT_CUSTOMER /= null loop 127 CONSOLE.WRITE(INTEGER(CURRENT_CUSTOMER.ID), 5); 128 CONSOLE.WRITE(" "); 129 CONSOLE.WRITE(FLOAT(CURRENT_CUSTOMER.BALANCE), 8, 2); 130 CONSOLE.WRITE(" "); 131 CONSOLE.WRITE(INTEGER(CURRENT_CUSTOMER.TRANSACTION_COUNT), 8); 132 CONSOLE.WRITE(" "); 133 CONSOLE.WRITE(INTEGER(CURRENT_CUSTOMER.ATTEMPTED_OVERDRAWS), 134 8); 135 CONSOLE.WRITE(CONSOLE.NEW_LINE); 136 CURRENT_CUSTOMER := CURRENT_CUSTOMER.NEXT; 137 end loop; 138 CONSOLE.WRITE(CONSOLE.NEW_LINE); 139 140 -- Teller transaction count report 141 CONSOLE.WRITE("Teller : "); 142 for I in TELLER_INDEX loop 143 CONSOLE.WRITE(INTEGER(I), 8); 144 end loop; 145 CONSOLE.WRITE(CONSOLE.NEW_LINE); 146 CONSOLE.WRITE("Transaction_Count: "); 147 for I in TELLER_INDEX loop 148 CONSOLE.WRITE(INTEGER(TELLER_TRANSACTION_COUNT(I)), 8); 149 end loop; 150 CONSOLE.WRITE(CONSOLE.NEW_LINE); 151 152 end if; 153 end PRINT_REPORT; 154 155 -- Terminate all TELLER tasks 156 procedure STOP_WORK is 157 begin 158 for I in TELLER_INDEX loop 159 abort TELLER(I); 160 end loop; 161 end STOP_WORK; 162 -- 163 -- package body BANK 164 165 -- FIND_CUSTOMER is used to find a CUSTOMER_DATA record 166 -- based on a CUSTOMER_ID number 167 function FIND_CUSTOMER(ID : in CUSTOMER_ID) 168 return CUSTOMER_DATA_POINTER is 169 CURRENT_CUSTOMER : CUSTOMER_DATA_POINTER; 170 begin 171 CURRENT_CUSTOMER := FIRST_CUSTOMER; 172 while CURRENT_CUSTOMER /= null loop 173 exit when CURRENT_CUSTOMER.ID = ID; 174 CURRENT_CUSTOMER := CURRENT_CUSTOMER.NEXT; 175 end loop; 176 return CURRENT_CUSTOMER; 177 end FIND_CUSTOMER; 178 179 180 -- 181 -- package body BANK 182 183 task TELLER_ASSIGNER is 184 -- This task assigns an ID number to a teller. 185 -- TELLER_ASSIGNER is called by the TELLER_PERSON task when the 186 -- TELLER_PERSON task first starts up. 187 entry GET_TELLER_ID(ID : out TELLER_INDEX); 188 end TELLER_ASSIGNER; 189 190 task body TELLER_ASSIGNER is 191 NEXT_TELLER_ID : TELLER_INDEX := TELLER_INDEX'FIRST; 192 begin 193 loop 194 accept GET_TELLER_ID(ID : out TELLER_INDEX) do 195 ID := NEXT_TELLER_ID; 196 if NEXT_TELLER_ID /= TELLER_INDEX'LAST then 197 NEXT_TELLER_ID := NEXT_TELLER_ID + 1; 198 end if; 199 end GET_TELLER_ID; 200 end loop; 201 end TELLER_ASSIGNER; 202 203 -- 204 -- package body BANK 205 206 -- Implementation of a TELLER task 207 task body TELLER_PERSON is 208 209 THIS_CUSTOMER : CUSTOMER_DATA_POINTER; 210 MY_NUMBER : TELLER_INDEX; 211 212 begin 213 214 -- TELLER gets his ID number 215 TELLER_ASSIGNER.GET_TELLER_ID(MY_NUMBER); 216 217 -- TELLER loops on REQUESTs from CUSTOMERs 218 loop 219 accept REQUEST(ID : in out CUSTOMER_ID; 220 KIND : in TRANSACTION; 221 AMOUNT : in out DOLLAR) do 222 223 -- Increment teller's transaction count 224 TELLER_TRANSACTION_COUNT(MY_NUMBER) 225 := TELLER_TRANSACTION_COUNT(MY_NUMBER) + 1; 226 227 -- 228 -- package body BANK 229 230 -- Process REQUEST 231 case KIND is 232 233 when ADD_NEW_CUSTOMER => 234 if LAST_CUSTOMER = null then 235 LAST_CUSTOMER := new CUSTOMER_DATA; 236 FIRST_CUSTOMER := LAST_CUSTOMER; 237 else 238 LAST_CUSTOMER.NEXT := new CUSTOMER_DATA; 239 LAST_CUSTOMER := LAST_CUSTOMER.NEXT; 240 end if; 241 LAST_CUSTOMER.ID := NEXT_ID; 242 ID := NEXT_ID; 243 NEXT_ID := NEXT_ID + 1; 244 THIS_CUSTOMER := LAST_CUSTOMER; 245 246 when GET_BALANCE => 247 THIS_CUSTOMER := FIND_CUSTOMER(ID); 248 AMOUNT := THIS_CUSTOMER.BALANCE; 249 250 when MAKE_DEPOSIT => 251 THIS_CUSTOMER := FIND_CUSTOMER(ID); 252 THIS_CUSTOMER.BALANCE 253 := THIS_CUSTOMER.BALANCE + AMOUNT; 254 AMOUNT := THIS_CUSTOMER.BALANCE; 255 256 when MAKE_WITHDRAWAL => 257 THIS_CUSTOMER := FIND_CUSTOMER(ID); 258 if THIS_CUSTOMER.BALANCE < AMOUNT then 259 AMOUNT := 0.0; 260 THIS_CUSTOMER.ATTEMPTED_OVERDRAWS := 261 THIS_CUSTOMER.ATTEMPTED_OVERDRAWS + 1; 262 else 263 THIS_CUSTOMER.BALANCE 264 := THIS_CUSTOMER.BALANCE - AMOUNT; 265 end if; 266 267 end case; 268 269 -- Increment CUSTOMER's transaction count 270 THIS_CUSTOMER.TRANSACTION_COUNT 271 := THIS_CUSTOMER.TRANSACTION_COUNT + 1; 272 273 end REQUEST; 274 275 end loop; 276 277 end TELLER_PERSON; 278 279 end BANK; 280 281 -- 282 package CUSTOMER_WORLD is 283 ------------------------------------------------------------------------ 284 --| BEGIN PROLOGUE 285 --| DESCRIPTION : CUSTOMER_WORLD is an abstract state machine 286 --| : which defines the collection of all CUSTOMERs 287 --| : of the BANK. It allows the mainline procedure 288 --| : to ADD a new CUSTOMER and TERMINATE_ALL 289 --| : current CUSTOMERs. The CUSTOMER itself acts 290 --| : as an independent task and requires no 291 --| : direct interaction with the mainline once 292 --| : it starts. 293 --| : 294 --| REQUIREMENTS SUPPORTED : Bank Demonstration Program to show 295 --| : object-oriented design and tasking 296 --| : with Ada 297 --| : 298 --| LIMITATIONS : None 299 --| AUTHOR(S) : Richard Conn (RLC) 300 --| CHANGE LOG : 1/16/89 RLC Initial Design and Code 301 --| CHANGE LOG : 2/25/89 RLC Final Review Prior to Release 302 --| REMARKS : None 303 --| PORTABILITY ISSUES : None 304 --| END PROLOGUE 305 ------------------------------------------------------------------------ 306 307 -- Add another CUSTOMER task to the system 308 procedure ADD; 309 310 -- Terminate all CUSTOMERs in the system 311 procedure TERMINATE_ALL; 312 313 end CUSTOMER_WORLD; 314 315 -- 316 with BANK; 317 with RANDOM; 318 package body CUSTOMER_WORLD is 319 320 -- Support infix operations, like DOLLAR < DOLLAR 321 use BANK; 322 323 -- This is the amount that a CUSTOMER initially deposits 324 -- into his account 325 INITIAL_DEPOSIT : constant BANK.DOLLAR := 100.0; 326 327 -- A CUSTOMER is a task, running concurrently with the TELLERs, 328 -- other CUSTOMERs, and the mainline task 329 task type CUSTOMER; 330 331 -- CUSTOMER_POINTER is a pointer to a CUSTOMER, used to 332 -- create new customers and track old customers in the linked 333 -- list of customers used for task termination when the 334 -- program is complete 335 type CUSTOMER_POINTER is access CUSTOMER; 336 337 -- These are the constructs used to create a linked list of 338 -- the customers 339 type CUSTOMER_LIST_ELEMENT; 340 type CUSTOMER_LIST_ELEMENT_POINTER is access CUSTOMER_LIST_ELEMENT; 341 type CUSTOMER_LIST_ELEMENT is record 342 THIS_CUSTOMER : CUSTOMER_POINTER; 343 NEXT : CUSTOMER_LIST_ELEMENT_POINTER := null; 344 end record; 345 346 -- Pointer to the first of the customers 347 FIRST_CUSTOMER : CUSTOMER_LIST_ELEMENT_POINTER := null; 348 LAST_CUSTOMER : CUSTOMER_LIST_ELEMENT_POINTER := null; 349 350 -- 351 -- package body CUSTOMER_WORLD 352 353 -- Implementation of the CUSTOMER task 354 task body CUSTOMER is 355 356 ID : BANK.CUSTOMER_ID := BANK.CUSTOMER_ID'FIRST; 357 BALANCE : BANK.DOLLAR := 0.0; 358 AMOUNT : BANK.DOLLAR := 0.0; 359 MY_TRANSACTION : BANK.TRANSACTION; 360 361 -- SELECT_TELLER makes a random selection of one of the 362 -- BANK's tellers 363 function SELECT_TELLER return BANK.TELLER_INDEX is 364 begin 365 return BANK.TELLER_INDEX( 366 RANDOM.NUMBER * FLOAT(BANK.TELLER_INDEX'LAST) + 1.0); 367 exception 368 when others => 369 return BANK.TELLER_INDEX'LAST; 370 end SELECT_TELLER; 371 372 begin -- CUSTOMER activity 373 374 -- As a new CUSTOMER, the first two transactions of the 375 -- CUSTOMER are to ask the TELLER to add him as a new 376 -- CUSTOMER and make an initial deposit 377 BANK.TELLER(SELECT_TELLER).REQUEST(ID, BANK.ADD_NEW_CUSTOMER, 378 BALANCE); 379 BALANCE := INITIAL_DEPOSIT; 380 BANK.TELLER(SELECT_TELLER).REQUEST(ID, BANK.MAKE_DEPOSIT, BALANCE); 381 382 -- The rest of the life of the CUSTOMER is spent in the 383 -- these steps within the following loop: 384 -- (1) delay a random amount of time from 0 to 5 seconds 385 -- (2) compute a random amount from -$50 to +$50 386 -- (3) if the random amount is negative, attempt to 387 -- withdraw that amount; if positive, deposit that 388 -- amount 389 loop 390 delay DURATION(5.0 * RANDOM.NUMBER); 391 AMOUNT := BANK.DOLLAR(100.0 * RANDOM.NUMBER - 50.0); 392 if AMOUNT < DOLLAR'(0.0) then 393 MY_TRANSACTION := BANK.MAKE_WITHDRAWAL; 394 AMOUNT := -AMOUNT; 395 else 396 MY_TRANSACTION := BANK.MAKE_DEPOSIT; 397 end if; 398 BANK.TELLER(SELECT_TELLER).REQUEST(ID, MY_TRANSACTION, AMOUNT); 399 end loop; 400 401 end CUSTOMER; 402 403 -- 404 -- package body CUSTOMER_WORLD 405 406 -- Add a new CUSTOMER to the linked list 407 procedure ADD is 408 begin 409 410 -- If the list is empty, start a new list 411 if LAST_CUSTOMER = null then 412 FIRST_CUSTOMER := new CUSTOMER_LIST_ELEMENT; 413 LAST_CUSTOMER := FIRST_CUSTOMER; 414 415 -- If the list is not empty, add an element onto it 416 else 417 LAST_CUSTOMER.NEXT := new CUSTOMER_LIST_ELEMENT; 418 LAST_CUSTOMER := LAST_CUSTOMER.NEXT; 419 end if; 420 421 -- Start a new CUSTOMER task 422 LAST_CUSTOMER.THIS_CUSTOMER := new CUSTOMER; 423 424 end ADD; 425 426 -- Terminate all CUSTOMER tasks by moving thru the linked list 427 -- and explicitly terminating the tasks pointed to by the list 428 -- elements. 429 procedure TERMINATE_ALL is 430 CURRENT_CUSTOMER : CUSTOMER_LIST_ELEMENT_POINTER; 431 begin 432 CURRENT_CUSTOMER := FIRST_CUSTOMER; 433 while CURRENT_CUSTOMER /= null loop 434 abort CURRENT_CUSTOMER.THIS_CUSTOMER.all; 435 CURRENT_CUSTOMER := CURRENT_CUSTOMER.NEXT; 436 end loop; 437 end TERMINATE_ALL; 438 439 end CUSTOMER_WORLD; 440 441 -- 442 with BANK; 443 with CUSTOMER_WORLD; 444 with CONSOLE; 445 procedure BD3 is -- BANK_DEMO_3 446 ------------------------------------------------------------------------ 447 --| BEGIN PROLOGUE 448 --| DESCRIPTION : Procedure BD3 (BANK DEMO 3) is a mainline 449 --| : which demonstrates the operation of the 450 --| : BANK. Upon invocation, the console becomes 451 --| : a command processor for the bank manager. 452 --| : The bank manager can obtain the status of 453 --| : the bank (balances, number of transactions, 454 --| : and attempted overdraws of all customers 455 --| : and number of transactions processed by all 456 --| : tellers) in a single or continuous (group 457 --| : of 11 over about one minute) display. 458 --| : The user at the console can also cause new 459 --| : Customer tasks to be created and shut down 460 --| : the system. 461 --| : 462 --| REQUIREMENTS SUPPORTED : Bank Demonstration Program to show 463 --| : object-oriented design and tasking 464 --| : with Ada 465 --| : 466 --| LIMITATIONS : None 467 --| AUTHOR(S) : Richard Conn (RLC) 468 --| CHANGE LOG : 1/16/89 RLC Initial Design and Code 469 --| CHANGE LOG : 2/25/89 RLC Final Review Prior to Release 470 --| REMARKS : None 471 --| PORTABILITY ISSUES : Uses CONSOLE (TEXT_IO), so is very portable; 472 --| : no known portability problems. 473 --| END PROLOGUE 474 ------------------------------------------------------------------------ 475 476 -- Line input from the console 477 INPUT : CONSOLE.OUTSTRING; 478 479 -- Number of continuous status reports displayed by the 'c' 480 -- command before control is returned to the console 481 NUMBER_OF_CONTINUOUS_STATUS_REPORTS : constant := 10; 482 483 -- 484 -- procedure BD3 485 486 begin -- mainline 487 488 -- This is the beginning of the main loop. In this loop, 489 -- a list of commands is printed on the console, the user 490 -- at the console (as CUSTOMER 0) enters one of these commands 491 -- followed by striking the RETURN key, and the command is 492 -- processed. 493 loop 494 495 -- Command listing and prompt 496 CONSOLE.WRITE("Enter"); 497 CONSOLE.WRITE(CONSOLE.NEW_LINE); 498 CONSOLE.WRITE(" b for bank status"); 499 CONSOLE.WRITE(CONSOLE.NEW_LINE); 500 CONSOLE.WRITE(" c for continuous bank status"); 501 CONSOLE.WRITE(CONSOLE.NEW_LINE); 502 CONSOLE.WRITE(" s for start next customer"); 503 CONSOLE.WRITE(CONSOLE.NEW_LINE); 504 CONSOLE.WRITE(" x for exit: "); 505 CONSOLE.READ(INPUT); 506 507 -- Interpretation and execution of input command 508 case INPUT(1) is 509 when 'b' | 'c' => -- Short or continuous bank status 510 -- report 511 BANK.PRINT_REPORT; 512 if INPUT(1) = 'c' then 513 for I in 1 .. NUMBER_OF_CONTINUOUS_STATUS_REPORTS loop 514 delay 5.0; 515 BANK.PRINT_REPORT; 516 CONSOLE.WRITE(CONSOLE.NEW_LINE); 517 end loop; 518 end if; 519 520 when 's' => -- Start up a new CUSTOMER 521 CUSTOMER_WORLD.ADD; 522 523 when 'x' => -- Exit program 524 CUSTOMER_WORLD.TERMINATE_ALL; -- Kill CUSTOMER tasks 525 BANK.STOP_WORK; -- Kill TELLER tasks 526 exit; -- Exit loop 527 528 when ' ' => -- Non-error on a null input line 529 null; 530 531 when others => -- Other commands are invalid 532 CONSOLE.WRITE("Invalid Command: "); 533 CONSOLE.WRITE(CONSOLE.TRIM(INPUT)); 534 CONSOLE.WRITE(CONSOLE.NEW_LINE); 535 536 end case; 537 538 end loop; 539 540 end BD3;