package inverview.optional;

import java.util.Optional;

public class OptionalTest {

public static void main(String[] args) {

String[] str = new String[10];

str[5] = "JAVA OPTIONAL CLASS EXAMPLE"; // Setting value for 5th index

// It returns an empty instance of Optional class

Optional<String> empty = Optional.empty();

System.out.println("empty: " + empty);

// System.out.println(empty.get());

// It returns a non-empty Optional

Optional<String> value = Optional.of(str[5]);

// If value is present, it returns an Optional otherwise returns an empty Optional

System.out.println("Filtered value: "+value.filter((s)->s.equals("Abc")));

System.out.println("Filtered value: "+value.filter((s)->s.equals("JAVA OPTIONAL CLASS EXAMPLE")));

// It returns value of an Optional. if value is not present, it throws an NoSuchElementException

System.out.println("Getting value: "+value.get());

// It returns hashCode of the value

System.out.println("Getting hashCode: "+value.hashCode());

// It returns true if value is present, otherwise false

System.out.println("Is value present: "+value.isPresent());

// It returns non-empty Optional if value is present, otherwise returns an empty Optional

System.out.println("Nullable Optional: "+Optional.ofNullable(str[5]));

// It returns value if available, otherwise returns specified value,

System.out.println("orElse: "+value.orElse("Value is not present"));

System.out.println("orElse: "+empty.orElse("Value is not present"));

value.ifPresent(System.out::println); // printing value by using method reference

}

}