// references/MutableInteger.java

// (c)2021 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.

// A changeable wrapper class

import java.util.*;

import java.util.stream.*;

class IntValue {

private int n;

IntValue(int x) { n = x; }

public int getValue() { return n; }

public void setValue(int n) { this.n = n; }

public void increment() { n++; }

@Override public String toString() {

return Integer.toString(n);

}

}

public class MutableInteger {

public static void main(String[] args) {

List<IntValue> v = IntStream.range(0, 10)

.mapToObj(IntValue::new)

.collect(Collectors.toList());

System.out.println(v);

v.forEach(IntValue::increment);

System.out.println(v);

}

}

/* Output:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

*/