import java.util.Optional;

import static java.lang.System.out;

/**

* Created by john on 2016/1/16.

*/

public class Java8OptionalExample {

public static void main(String[] args) {

Java8OptionalExample example = new Java8OptionalExample();

Integer value1 = null;

Integer value2 = new Integer(10);

//Optional.ofNullable - allows passed parameter to be null

Optional<Integer> a = Optional.ofNullable(value1);

//Optional.of - throws NullPointerException if passed parameter is null

Optional<Integer> b = Optional.of(value2);

System.out.println(example.sum(a,b));

}

public Integer sum(Optional<Integer> a, Optional<Integer> b) {

//Optional.isPresent - checks the value is present or not

out.println("First parameter is present: "+a.isPresent());

out.println("Second parameter is present: "+b.isPresent());

//Optional.orElse - return the value if present otherwise returns

// the default value pressed

Integer value1 = a.orElse(new Integer(0));

//Optional.get - get the value, value should be present

Integer value2 = b.get();

return value1 + value2;

}

}