Wed Dec 26 16:00:00 GMT 2001

VendingMachine

//: c04:vendingmachine:VendingMachine.java // Demonstrates use of StateMachine.java package c04.vendingmachine; import c04.statemachine2.*; final class VM extends State { private VM(String nm) { super(nm); } public final static VM quiescent = new VM("Quiesecent"), collecting = new VM("Collecting"), selecting = new VM("Selecting"), unavailable = new VM("Unavailable"), wantMore = new VM("Want More?"), noChange = new VM("Use Exact Change Only"), makesChange = new VM("Machine makes change"); } final class HasChange implements Input { private String name; private HasChange(String nm) { name = nm; } public String toString() { return name; } public final static HasChange yes = new HasChange("Has change"), no = new HasChange("Cannot make change"); } class ChangeAvailable extends StateMachine { public ChangeAvailable() { super(VM.makesChange); buildTable(new Object[][][]{ { {VM.makesChange}, // Current state // Input, test, transition, next state: {HasChange.no, null, null, VM.noChange}}, { {VM.noChange}, // Current state // Input, test, transition, next state: {HasChange.yes, null, null, VM.makesChange}}, }); } } final class Money implements Input { private String name; private int value; private Money(String nm, int val) { name = nm; value = val; } public String toString() { return name; } public int getValue() { return value; } public final static Money quarter = new Money("Quarter", 25), dollar = new Money("Dollar", 100); } final class Quit implements Input { private Quit() {} public String toString() { return "Quit"; } public final static Quit quit = new Quit(); } final class FirstDigit implements Input { private String name; private int value; private FirstDigit(String nm, int val) { name = nm; value = val; } public String toString() { return name; } public int getValue() { return value; } public final static FirstDigit A = new FirstDigit("A", 0), B = new FirstDigit("B", 1), C = new FirstDigit("C", 2), D = new FirstDigit("D", 3); } final class SecondDigit implements Input { private String name; private int value; private SecondDigit(String nm, int val) { name = nm; value = val; } public String toString() { return name; } public int getValue() { return value; } public final static SecondDigit one = new SecondDigit("one", 0), two = new SecondDigit("two", 1), three = new SecondDigit("three", 2), four = new SecondDigit("four", 3); } class ItemSlot { int price; int quantity; static int counter = 0; String id = Integer.toString(counter++); public ItemSlot(int prc, int quant) { price = prc; quantity = quant; } public String toString() { return id; } public int getPrice() { return price; } public int getQuantity() { return quantity; } public void decrQuantity() { quantity--; } } public class VendingMachine extends StateMachine{ StateMachine changeAvailable = new ChangeAvailable(); int amount = 0; FirstDigit first = null; ItemSlot[][] items = new ItemSlot[4][4]; Condition notEnough = new Condition() { public boolean condition(Input input) { int i1 = first.getValue(); int i2 = ((SecondDigit)input).getValue(); return items[i1][i2].getPrice() > amount; } }; Condition itemAvailable = new Condition() { public boolean condition(Input input) { int i1 = first.getValue(); int i2 = ((SecondDigit)input).getValue(); return items[i1][i2].getQuantity() > 0; } }; Condition itemNotAvailable = new Condition() { public boolean condition(Input input) { return !itemAvailable.condition(input); //int i1 = first.getValue(); //int i2 = ((SecondDigit)input).getValue(); //return items[i1][i2].getQuantity() == 0; } }; Transition clearSelection = new Transition() { public void transition(Input input) { int i1 = first.getValue(); int i2 = ((SecondDigit)input).getValue(); ItemSlot is = items[i1][i2]; System.out.println( "Clearing selection: item " + is + " costs " + is.getPrice() + " and has quantity " + is.getQuantity()); first = null; } }; Transition dispense = new Transition() { public void transition(Input input) { int i1 = first.getValue(); int i2 = ((SecondDigit)input).getValue(); ItemSlot is = items[i1][i2]; System.out.println("Dispensing item " + is + " costs " + is.getPrice() + " and has quantity " + is.getQuantity()); items[i1][i2].decrQuantity(); System.out.println("New Quantity " + is.getQuantity()); amount -= is.getPrice(); System.out.println("Amount remaining " + amount); } }; Transition showTotal = new Transition() { public void transition(Input input) { amount += ((Money)input).getValue(); System.out.println("Total amount = " + amount); } }; Transition returnChange = new Transition() { public void transition(Input input) { System.out.println("Returning " + amount); amount = 0; } }; Transition showDigit = new Transition() { public void transition(Input input) { first = (FirstDigit)input; System.out.println("First Digit= "+ first); } }; public VendingMachine() { super(VM.quiescent); // Initial state for(int i = 0; i < items.length; i++) for(int j = 0; j < items[i].length; j++) items[i][j] = new ItemSlot((j+1)*25, 5); items[3][0] = new ItemSlot(25, 0); buildTable(new Object[][][]{ { {VM.quiescent}, // Current state // Input, test, transition, next state: {Money.class, null, showTotal, VM.collecting}}, { {VM.collecting}, // Current state // Input, test, transition, next state: {Quit.quit, null, returnChange, VM.quiescent}, {Money.class, null, showTotal, VM.collecting}, {FirstDigit.class, null, showDigit, VM.selecting}}, { {VM.selecting}, // Current state // Input, test, transition, next state: {Quit.quit, null, returnChange, VM.quiescent}, {SecondDigit.class, notEnough, clearSelection, VM.collecting}, {SecondDigit.class, itemNotAvailable, clearSelection, VM.unavailable}, {SecondDigit.class, itemAvailable, dispense, VM.wantMore}}, { {VM.unavailable}, // Current state // Input, test, transition, next state: {Quit.quit, null, returnChange, VM.quiescent}, {FirstDigit.class, null, showDigit, VM.selecting}}, { {VM.wantMore}, // Current state // Input, test, transition, next state: {Quit.quit, null, returnChange, VM.quiescent}, {FirstDigit.class, null, showDigit, VM.selecting}}, }); } } ///:~


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