first draft state

assignments/state_pattern/GumballMachine.java

@@ -0,0 +1,93 @@
+package assignments.state_pattern;
+
+public class GumballMachine {
+    private GumballMachineState soldOutState;
+    private GumballMachineState noQuarterState;
+    private GumballMachineState hasQuarterState;
+    private GumballMachineState soldState;
+    private GumballMachineState winnerState;
+
+    private int count = 0;
+    private GumballMachineState currentState;
+
+    public GumballMachine(int numberGumballs) {
+        soldOutState = new SoldOutState(this);
+        noQuarterState = new NoQuarterState(this);
+        hasQuarterState = new HasQuarterState(this);
+        soldState = new SoldState(this);
+        winnerState = new WinnerState(this);
+
+        this.count = numberGumballs;
+
+        currentState = (numberGumballs > 0) ? noQuarterState : soldOutState;
+    }
+
+    public void setState(GumballMachineState currentState) {
+        this.currentState = currentState;
+    }
+
+    public void insertQuarter() {
+        currentState.insertQuarter();
+    }
+
+    public void ejectQuarter() {
+        currentState.ejectQuarter();
+    }
+
+    public void turnCrank() {
+        currentState.turnCrank();
+        currentState.dispense();
+    }
+
+    public void releaseBall() {
+        System.out.println("A gumball comes rolling out the slot...");
+        if (count > 0) {
+            count = count - 1;
+        }
+    }
+
+    public int getCount() {
+        return count;
+    }
+
+    public GumballMachineState getNoQuarterState() {
+        return noQuarterState;
+    }
+
+    public GumballMachineState getHasQuarterState() {
+        return hasQuarterState;
+    }
+
+    public GumballMachineState getSoldOutState() {
+        return soldOutState;
+    }
+
+    public GumballMachineState getSoldState() {
+        return soldState;
+    }
+
+    public GumballMachineState getWinnerState() {
+        return winnerState;
+    }
+
+    public void refill(int count) {
+        this.count += count;
+        System.out.println("The gumball machine was just refilled; its new count is: " + this.count);
+        if (currentState == soldOutState) {
+            currentState = noQuarterState;
+        }
+    }
+
+    public String toString() {
+        StringBuffer result = new StringBuffer();
+        result.append("\nMighty Gumball, Inc.");
+        result.append("\nJava-enabled Standing Gumball Model #2004");
+        result.append("\nInventory: " + count + " gumball");
+        if (count != 1) {
+            result.append("s");
+        }
+        result.append("\n");
+        result.append("Machine is " + currentState.getStateToString() + "\n");
+        return result.toString();
+    }
+}

assignments/state_pattern/GumballMachineState.java

@@ -0,0 +1,15 @@
+package assignments.state_pattern;
+
+//State Interface
+//Should showcase actions on the state only
+public interface GumballMachineState {
+    void insertQuarter();
+
+    void ejectQuarter();
+
+    void turnCrank();
+
+    void dispense();
+
+    String getStateToString();
+}

assignments/state_pattern/GumballMachineTestDrive.java

@@ -0,0 +1,45 @@
+package assignments.state_pattern;
+
+public class GumballMachineTestDrive {
+
+    public static void main(String[] args) {
+        GumballMachine gumballMachine = new GumballMachine(10);
+
+        System.out.println(gumballMachine);
+
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+
+        System.out.println(gumballMachine);
+
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+
+        System.out.println(gumballMachine);
+
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+
+        System.out.println(gumballMachine);
+
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+
+        System.out.println(gumballMachine);
+
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+        gumballMachine.insertQuarter();
+        gumballMachine.turnCrank();
+
+        System.out.println(gumballMachine);
+    }
+}

assignments/state_pattern/HasQuarterState.java

@@ -0,0 +1,44 @@
+package assignments.state_pattern;
+
+import java.util.Random;
+
+public class HasQuarterState implements GumballMachineState {
+    private Random randomWinner = new Random(System.currentTimeMillis());
+    private GumballMachine gumballMachine;
+
+    public HasQuarterState(GumballMachine gumballMachine) {
+        this.gumballMachine = gumballMachine;
+    }
+
+    @Override
+    public void insertQuarter() {
+        System.out.println("You can't insert another quarter");
+    }
+
+    @Override
+    public void ejectQuarter() {
+        System.out.println("Quarter returned");
+        gumballMachine.setState(gumballMachine.getNoQuarterState());
+    }
+
+    @Override
+    public void turnCrank() {
+        System.out.println("You turned...");
+        int winner = randomWinner.nextInt(10);
+        if ((winner == 0) && (gumballMachine.getCount() > 1)) {
+            gumballMachine.setState(gumballMachine.getWinnerState());
+        } else {
+            gumballMachine.setState(gumballMachine.getSoldState());
+        }
+    }
+
+    @Override
+    public void dispense() {
+        System.out.println("No gumball dispensed");
+    }
+
+    @Override
+    public String getStateToString() {
+        return "waiting for turn of crank";
+    }
+}

assignments/state_pattern/NoQuarterState.java

@@ -0,0 +1,35 @@
+package assignments.state_pattern;
+
+public class NoQuarterState implements GumballMachineState {
+    private GumballMachine gumballMachine;
+
+    public NoQuarterState(GumballMachine gumballMachine) {
+        this.gumballMachine = gumballMachine;
+    }
+
+    @Override
+    public void insertQuarter() {
+        System.out.println("You inserted a quarter");
+        gumballMachine.setState(gumballMachine.getHasQuarterState());
+    }
+
+    @Override
+    public void ejectQuarter() {
+        System.out.println("You haven't inserted a quarter");
+    }
+
+    @Override
+    public void turnCrank() {
+        System.out.println("You turned, but there's no quarter");
+    }
+
+    @Override
+    public void dispense() {
+        System.out.println("You need to pay first");
+    }
+
+    @Override
+    public String getStateToString() {
+        return "waiting for quarter";
+    }
+}

assignments/state_pattern/SoldOutState.java

@@ -0,0 +1,34 @@
+package assignments.state_pattern;
+
+public class SoldOutState implements GumballMachineState {
+    private GumballMachine gumballMachine;
+
+    public SoldOutState(GumballMachine gumballMachine) {
+        this.gumballMachine = gumballMachine;
+    }
+
+    @Override
+    public void insertQuarter() {
+        System.out.println("You can't insert a quarter, the machine is sold out");
+    }
+
+    @Override
+    public void ejectQuarter() {
+        System.out.println("You can't eject, you haven't inserted a quarter yet");
+    }
+
+    @Override
+    public void turnCrank() {
+        System.out.println("You turned, but there are no gumballs");
+    }
+
+    @Override
+    public void dispense() {
+        System.out.println("No gumball dispensed");
+    }
+
+    @Override
+    public String getStateToString() {
+        return "sold out";
+    }
+}

assignments/state_pattern/SoldState.java

@@ -0,0 +1,40 @@
+package assignments.state_pattern;
+
+public class SoldState implements GumballMachineState {
+    private GumballMachine gumballMachine;
+
+    public SoldState(GumballMachine gumballMachine) {
+        this.gumballMachine = gumballMachine;
+    }
+
+    @Override
+    public void insertQuarter() {
+        System.out.println("Please wait, we're already giving you a gumball");
+    }
+
+    @Override
+    public void ejectQuarter() {
+        System.out.println("Sorry, you already turned the crank");
+    }
+
+    @Override
+    public void turnCrank() {
+        System.out.println("Turning twice doesn't get you another gumball!");
+    }
+
+    @Override
+    public void dispense() {
+        gumballMachine.releaseBall();
+        if (gumballMachine.getCount() > 0) {
+            gumballMachine.setState(gumballMachine.getNoQuarterState());
+        } else {
+            System.out.println("Oops, out of gumballs!");
+            gumballMachine.setState(gumballMachine.getSoldOutState());
+        }
+    }
+
+    @Override
+    public String getStateToString() {
+        return "dispensing a gumball";
+    }
+}

assignments/state_pattern/WinnerState.java

@@ -0,0 +1,46 @@
+package assignments.state_pattern;
+
+public class WinnerState implements GumballMachineState {
+    private GumballMachine gumballMachine;
+
+    public WinnerState(GumballMachine gumballMachine) {
+        this.gumballMachine = gumballMachine;
+    }
+
+    @Override
+    public void insertQuarter() {
+        System.out.println("Please wait, we're already giving you a Gumball");
+    }
+
+    @Override
+    public void ejectQuarter() {
+        System.out.println("Sorry, you already turned the crank");
+    }
+
+    @Override
+    public void turnCrank() {
+        System.out.println("Turning again doesn't get you another gumball!");
+    }
+
+    @Override
+    public void dispense() {
+        gumballMachine.releaseBall();
+        if (gumballMachine.getCount() <= 0) {
+            gumballMachine.setState(gumballMachine.getSoldOutState());
+        } else {
+            gumballMachine.releaseBall();
+            System.out.println("YOU'RE A WINNER! You got two gumballs for your quarter");
+            if (gumballMachine.getCount() > 0) {
+                gumballMachine.setState(gumballMachine.getNoQuarterState());
+            } else {
+                System.out.println("Oops, out of gumballs!");
+                gumballMachine.setState(gumballMachine.getSoldOutState());
+            }
+        }
+    }
+
+    @Override
+    public String getStateToString() {
+        return "despensing two gumballs for your quarter, because YOU'RE A WINNER!";
+    }
+}