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Importance of Predicate interface in lambda expression in Java?
Predicate<T> is a generic functional interface that represents a single argument function that returns a boolean value (true or false). This interface available in java.util.function package and contains a test(T t) method that evaluates the predicate of a given argument.
Syntax
public interface Predicate {
boolean test(T t);
}Example
import java.util.*;
import java.util.functionPredicate;
public class LambdaPredicateTest {
public static void main(String args[]) {
Employee emp1 = new Employee("Raja", 26);
Employee emp2 = new Employee("Jaidev", 24);
Employee emp3 = new Employee("Adithya", 30);
List<Employee> empList = new ArrayList<Employee>();
empList.add(emp1);
empList.add(emp2);
empList.add(emp3);
Predicate<Employee> predicateForAge = (e) -> e.age >= 25;
Predicate<Employee> predicateForName = (e) -> e.name.startsWith("A");
for(Employee emp : empList) {
if(predicateForAge.test(emp)) {
System.out.println(emp.name +" is eligible by age");
}
}
System.out.println("----------------------------");
for(Employee emp : empList) {
if(predicateForName.test(emp)) {
System.out.println(emp.name +" is eligible by name");
}
}
}
}
// Employee class
class Employee {
public String name;
public int age;
public Employee(String name,int age){
this.name=name;
this.age=age;
}
}Output
Raja is eligible by age Adithya is eligible by age ---------------------------- Adithya is eligible by name
Updated on: 11-Jul-2020
2K+ Views
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