Function interface andThen method, compose method

f1.andThen(f2)は、f1,f2
f1.compose(f2)は、f2,f1

下記の例
fc1 integer→string, string→integer
fc2 string→integer, integer→string

public class Outer {
    public static void main(String[] args) {
        Function<Integer, String> f1 = x -> String.valueOf(x + 2);
        Function<String, Integer> f2 = x -> Integer.valueOf(x) * 2;
        Function<Integer, Integer> fc1 = f1.andThen(f2);
        System.out.println(fc1.apply(5));
        System.out.println(f1.andThen(f2).apply(5));
        Function<String, String> fc2 = f1.compose(f2);
        System.out.println(fc2.apply("5"));
        System.out.println(f1.compose(f2).apply("5"));
    }

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