Java8 method reference used as Function object to combine functions

Question

Is there a way in Java8 to use a method reference as a Function object to use its methods, something like:

Stream.of(\"ciao\", \"hola\", \"hello         


        

Answer 1

We can use reduce function to combine multiple functions into one.

public static void main(String[] args) {
    List<Function<String, String>> normalizers = Arrays.asList(
    str -> {
        System.out.println(str);
        return str;
    }, 
    String::toLowerCase,
    str -> {
        System.out.println(str);
        return str;
    },
    String::trim,
    str -> {
        System.out.println(str);
        return str;
    });

    String input = " Hello World ";
    normalizers.stream()
               .reduce(Function.identity(), (a, b) -> a.andThen(b))
               .apply(input);
}

Output:

 Hello World 
 hello world 
hello world