OptionalExample.java

package com.learn.optional;

import com.learn.data.Student;
import com.learn.data.StudentDataBase;

import java.util.Optional;


public class OptionalExample {

 public static void main(String[] args) {

 String studentName = getStudentName();
 if (studentName != null) {
 System.out.println("Length of Student Name " + studentName.length());
 }else {
 System.out.println("Name not found.");
 }


 Optional<String> studentNameOptional = getStudentNameOptional();
 if (studentNameOptional.isPresent()) {
 System.out.println("Length of Student Name Optional : " + studentNameOptional.get().length()); // to get actual value inside Optional.
 }else {
 System.out.println("Name not found.");
 }

 }

 /**
 * Too many null Checks.
 * @return
 */
 public static String getStudentName() {
 Student student = StudentDataBase.studentSupplier.get();
 // if student == null, then it return null
 if (student == null) {
 return null;
 }
 return student.getName();
 }

 public static Optional<String> getStudentNameOptional() {
 // wrapping actual Student Object within Optional
 Optional<Student> studentOptional = Optional.ofNullable(StudentDataBase.studentSupplier.get());

 // Checks whether is this Optional Object has any value inside that object or not.
 if (studentOptional.isPresent()) {
 return studentOptional.map(Student::getName); // this return Optional<String>
 }
 return Optional.empty(); // Represents an Optional Object with no value.
 }
}