//三項関数(S×T×U→R)の自作インターフェース
@FunctionalInterface
interface TriFunction<S,T,U,R> {
	R apply(S s, T t, U u);
}

public class TriFunctionTest {
	public static void main(String[] args) {
		//3つ文字列を連結
		TriFunction<String,String,String,String> tf1 = (a,b,c) -> a+b+c;
		System.out.println(tf1.apply("foo","bar","baz"));

		//三項演算(条件分岐)
		TriFunction<Boolean, Number, Number, Number> tf2 = (cond, v, w) -> cond ? v : w;
		System.out.println(tf2.apply(true, 1, 2));
	}
}