In order to negate an existing predicate, the Predicate.not() static method added to Java 11. The Predicate class is present in java.util.function package.
Syntax:
negate = Predicate.not( positivePredicate );
Parameters:
- Predicate whose negate is required
Return Type: Return type not() method is Predicate.
Approach:
- Create one predicate and initialize the conditions to it.
- Create another predicate to create negate and assign it with the not() method.
Below is the implementation of the above approach:
Java
// Implementation of Predicate.not() method in Javaimport java.util.Arrays;import java.util.List;import java.util.function.Predicate;import java.util.stream.Collectors; public class GFG { public static void main(String[] args) { List<Integer> list = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10); // creating a predicate for negation Predicate<Integer> even = i -> i % 2 == 0; // creating a predicate object which // is negation os supplied predicate Predicate<Integer> odd = Predicate.not(even); // filtering the even number using even predicate List<Integer> evenNumbers = list.stream().filter(even).collect( Collectors.toList()); // filtering the odd number using odd predicate List<Integer> oddNumbers = list.stream().filter(odd).collect( Collectors.toList()); // Print the Lists System.out.println(evenNumbers); System.out.println(oddNumbers); }} |
Output:
[2, 4, 6, 8, 10] [1, 3, 5, 7, 9]
