ステータスモード

油抜き機

package statepattern;

public class GumballMachine {
    final static int SOLD_OUT = 0;
    final static int NO_QUARTER = 1;
    final static int HAS_QUARTER = 2;
    final static int SOLD = 3;

    int state = SOLD_OUT;
    int count = 0;


    public GumballMachine(int count) {
        this.count = count;
        if (count > 0) {
            state = NO_QUARTER;
        }
    }

    public void insertQuarter() {
        if (state == HAS_QUARTER) {
            System.out.println("One Coin only");
        } else if (state == NO_QUARTER) {
            state = HAS_QUARTER;
        } else if (state == SOLD_OUT) {
            System.out.println("Sold out");
        } else if (state == SOLD) {
            System.out.println("Wait, the ball will soon be yours");
        }
    }

    public void ejectQuarter() {
        if (state == HAS_QUARTER) {
            System.out.println("Returning coin");
            state = NO_QUARTER;
        } else if (state == NO_QUARTER) {
            System.out.println("No Quarter to return");
        } else if (state == SOLD_OUT) {
            System.out.println("You did not insert a token");
        } else if (state == SOLD) {
            System.out.println("You already bought a ball");
        }
    }

    public void turnCrank() {
        if (state == HAS_QUARTER) {
            System.out.println("Crank turned");
            state = SOLD;
            dispense();
            state = NO_QUARTER;
        } else if (state == NO_QUARTER) {
            System.out.println("No Quarter to turn Crank");
        } else if (state == SOLD_OUT) {
            System.out.println("Sorry, SoldOut");
        } else if (state == SOLD) {
            System.out.println("You already bought a ball");
        }
    }

    private void dispense() {
        if (state == SOLD) {
            System.out.println("Ball is being dispensed");
            count -= 1;
            if (count == 0) {
                System.out.println("No balls left");
                state = SOLD_OUT;
            } else {
                state = NO_QUARTER;
            }
        } else if (state == NO_QUARTER) {
            System.out.println("Insert a Coin");
        } else if (state == SOLD_OUT) {
            System.out.println("Sold Out");
        } else if (state == HAS_QUARTER) {
            System.out.println("Ball Stuck");
        }
    }
}

状態モードの適用

変更

完全なコード