State Pattern + Singleton Implementation

Design Patterns/src/state/atm/with/singleton/ATMMachine.java

@@ -0,0 +1,56 @@
+package state.atm.with.singleton;
+
+public class ATMMachine {
+
+    private ATMState atmState;
+    private int cashInMachine;
+    private boolean correctPinEntered = false;
+
+    public ATMMachine() {
+        this.atmState = NoCard.getInstance(this);
+    }
+
+    public void changeATMMachineState(ATMState atmState) {
+        this.atmState = atmState;
+    }
+
+    public void setCashInMachine(int cashInMachine){
+        this.cashInMachine = cashInMachine;
+    }
+
+    public void insertCard() {
+        atmState.insertCard();
+    }
+
+    public void ejectCard() {
+        atmState.ejectCard();
+    }
+
+    public void requestCash(int cashToWithdraw) {
+        atmState.requestCash(cashToWithdraw);
+    }
+
+    public void insertPin(int pinEntered){
+        atmState.insertPin(pinEntered);
+    }
+
+    public ATMState getAtmState() {
+        return atmState;
+    }
+
+    public void setAtmState(ATMState atmState) {
+        this.atmState = atmState;
+    }
+
+    public int getCashInMachine() {
+        return cashInMachine;
+    }
+
+    public boolean isCorrectPinEntered() {
+        return correctPinEntered;
+    }
+
+    public void setCorrectPinEntered(boolean correctPinEntered) {
+        this.correctPinEntered = correctPinEntered;
+    }
+}

Design Patterns/src/state/atm/with/singleton/ATMState.java

@@ -0,0 +1,9 @@
+package state.atm.with.singleton;
+
+public interface ATMState {
+
+    void insertCard();
+    void ejectCard();
+    void insertPin(int pinEntered);
+    void requestCash(int cashToWithdraw);
+}

Design Patterns/src/state/atm/with/singleton/HasCard.java

@@ -0,0 +1,44 @@
+package state.atm.with.singleton;
+
+public class HasCard implements ATMState {
+
+    ATMMachine atmMachine;
+    private static HasCard instance;
+
+    private HasCard(ATMMachine atmMachine) {
+        this.atmMachine = atmMachine;
+    }
+
+    public static HasCard getInstance(ATMMachine atmMachine) {
+        return instance == null ? instance = new HasCard(atmMachine) : instance;
+    }
+
+    @Override
+    public void insertCard() {
+        System.out.println("You can only insert one card at a time");
+    }
+
+    @Override
+    public void ejectCard() {
+        System.out.println("Your card is ejected");
+        atmMachine.changeATMMachineState(NoCard.getInstance(atmMachine));
+    }
+
+    @Override
+    public void requestCash(int cashToWithdraw) {
+        System.out.println("You have not entered your PIN");
+    }
+
+    @Override
+    public void insertPin(int pinEntered) {
+
+        if (pinEntered == 1234) {
+            System.out.println("Correct PIN entered");
+            atmMachine.setCorrectPinEntered(true);
+            atmMachine.changeATMMachineState(HasPin.getInstance(atmMachine));
+        } else {
+            System.out.println("You entered the wrong PIN");
+            atmMachine.setCorrectPinEntered(false);
+        }
+    }
+}

Design Patterns/src/state/atm/with/singleton/HasPin.java

@@ -0,0 +1,48 @@
+package state.atm.with.singleton;
+
+public class HasPin implements ATMState {
+
+    ATMMachine atmMachine;
+    private static HasPin instance;
+
+    private HasPin(ATMMachine atmMachine) {
+        this.atmMachine = atmMachine;
+    }
+
+    public static HasPin getInstance(ATMMachine atmMachine) {
+        return instance == null ? instance = new HasPin(atmMachine) : instance;
+    }
+
+    @Override
+    public void insertCard() {
+        System.out.println("You have already inserted a card");
+    }
+
+    @Override
+    public void ejectCard() {
+        System.out.println("Your card is ejected");
+        atmMachine.changeATMMachineState(NoCard.getInstance(atmMachine));
+    }
+
+    @Override
+    public void insertPin(int pinEntered) {
+        System.out.println("You've already entered a pin");
+    }
+
+    @Override
+    public void requestCash(int cashToWithdraw) {
+
+        if (cashToWithdraw > atmMachine.getCashInMachine()) {
+            System.out.println("You don't have enough cash to withdraw");
+        } else {
+            System.out.println("Cash Withdrawn: " + cashToWithdraw);
+            atmMachine.setCashInMachine(atmMachine.getCashInMachine() - cashToWithdraw);
+
+            if (atmMachine.getCashInMachine() <= 0)
+                atmMachine.changeATMMachineState(NoCash.getInstance(atmMachine));
+        }
+
+        System.out.println("Your card is ejected");
+        atmMachine.changeATMMachineState(NoCash.getInstance(atmMachine));
+    }
+}

Design Patterns/src/state/atm/with/singleton/Main.java

@@ -0,0 +1,31 @@
+package state.atm.with.singleton;
+
+public class Main {
+    public static void main(String[] args) {
+
+        ATMMachine atmMachine = new ATMMachine();
+        atmMachine.setCashInMachine(200);
+
+        sleep(1000);
+
+        atmMachine.insertCard();
+        atmMachine.ejectCard();
+
+        sleep(1000);
+
+        atmMachine.insertCard();
+        atmMachine.insertPin(1111);
+
+        sleep(1000);
+
+        atmMachine.insertPin(1234);
+        atmMachine.requestCash(100);
+    }
+
+    static void sleep(int timeToSleep) {
+        try {Thread.sleep(timeToSleep);}
+        catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+}

Design Patterns/src/state/atm/with/singleton/NoCard.java

@@ -0,0 +1,36 @@
+package state.atm.with.singleton;
+
+public class NoCard implements ATMState {
+
+    ATMMachine atmMachine;
+    private static NoCard instance;
+
+    private NoCard(ATMMachine atmMachine) {
+        this.atmMachine = atmMachine;
+    }
+
+    public static NoCard getInstance(ATMMachine atmMachine) {
+        return instance == null ? instance = new NoCard(atmMachine) : instance;
+    }
+
+    @Override
+    public void insertCard() {
+        System.out.println("Card has been inserted");
+        atmMachine.changeATMMachineState(HasCard.getInstance(atmMachine));
+    }
+
+    @Override
+    public void ejectCard() {
+        System.out.println("You didn't insert a card");
+    }
+
+    @Override
+    public void insertPin(int pinEntered) {
+        System.out.println("You have not entered your card");
+    }
+
+    @Override
+    public void requestCash(int cashToWithdraw) {
+        System.out.println("You have not inserted your card");
+    }
+}

Design Patterns/src/state/atm/with/singleton/NoCash.java

@@ -0,0 +1,37 @@
+package state.atm.with.singleton;
+
+public class NoCash implements ATMState {
+
+    ATMMachine atmMachine;
+    private static NoCash instance;
+
+    private NoCash(ATMMachine atmMachine) {
+        this.atmMachine = atmMachine;
+    }
+
+    public static NoCash getInstance(ATMMachine atmMachine) {
+        return instance == null ? instance = new NoCash(atmMachine) : instance;
+    }
+
+    @Override
+    public void insertCard() {
+        System.out.println("We don't have any money");
+        System.out.println("Your card is ejected");
+    }
+
+    @Override
+    public void ejectCard() {
+        System.out.println("We don't have any money");
+        System.out.println("There is no card to eject");
+    }
+
+    @Override
+    public void insertPin(int pinEntered) {
+        System.out.println("We don't have any money");
+    }
+
+    @Override
+    public void requestCash(int cashToWithdraw) {
+        System.out.println("We don't have any money");
+    }
+}