// streams/FunctionMap.java

// (c)2017 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

import java.util.*;

import java.util.stream.*;

import java.util.function.*;

class FunctionMap {

static String[] elements = { "12", "", "23", "45" };

static Stream<String> testStream() {

return Arrays.stream(elements);

}

static void

test(String descr, Function<String, String> func) {

System.out.println(" ---( " + descr + " )---");

testStream()

.map(func)

.forEach(System.out::println);

}

public static void main(String[] args) {

test("add brackets", s -> "[" + s + "]");

test("Increment", s -> {

try {

return Integer.parseInt(s) + 1 + "";

} catch(NumberFormatException e) {

return s;

}

});

test("Replace", s -> s.replace("2", "9"));

test("Take last digit", s -> s.length() > 0 ?

s.charAt(s.length() - 1) + "" : s);

}

}

/* Output:

---( add brackets )---

[12]

[]

[23]

[45]

---( Increment )---

13

24

46

---( Replace )---

19

93

45

---( Take last digit )---

2

3

5

*/