enum, 이늄

animal.java

public enum Animal {
	CAT {
		public String makeNoise() { return "MEOW!";	}
	},
	DOG{
		public String makeNoise() { return "WOOF!";	}
	},
	HORSE{
		public String makeNoise() { return "NEIGH!";	}
	};
	public abstract String makeNoise();
}

이늄함수형.java

public class HelloWorld {
public static void main(String[] args) {
System.out.print(Calc.PLUS.calc(3,4));
}

static enum Calc {
PLUS((Integer o1, Integer o2) -> o1 + o2),
MINUS((Integer o1, Integer o2) -> o1 - o2);

private final BiFunction<integer,integer,integer> op;

Calc(BiFunction<integer,integer,integer> op) {
this.op = op;
}

public int calc(int o1, int o2) {
return op.apply(o1,o2);
}
}
}