import java.util.Collections;

import java.util.List;

import java.util.ArrayList;

public class UnmodifiableListTest {

private static void printPersons(List<Person> persons) {

for (Person p : persons) {

System.out.print(p.name() + ", ");

}

System.out.println("");

}

public static void main(String[] args) {

List<Person> persons = new ArrayList<Person>();

persons.add(new Person("Yalun", 25));

persons.add(new Person("Jack", 30));

persons.add(new Person("Lucy", 16));

List<Person> unmodifiablePersons = Collections.unmodifiableList(persons);

System.out.println("Original: ");

printPersons(unmodifiablePersons);

// Try changing the collection through the view

try {

//unmodifiablePersons.add(new Person("Tim", 44));

unmodifiablePersons.remove(0);

} catch (UnsupportedOperationException e) {

System.out.println("UnsupportedOperationException!");

}

System.out.println("Now the array content is still:");

printPersons(unmodifiablePersons);

// Make a change to one element throught the view

try {

for (Person p : unmodifiablePersons) {

if (p.name().equals("Lucy")) {

p.setName("Jane");

}

}

} catch (Exception e) {

System.out.println("Exception!");

}

System.out.println("After making changes of an element through the view:");

printPersons(unmodifiablePersons);

System.out.println("Original list now is: ");

printPersons(persons);

// Remove the first element in the original array

try {

persons.remove(0);

persons.add(new Person("Tim", 44));

} catch (Exception e) {

System.out.println("Exception!");

}

System.out.println("After changing the original array: ");

printPersons(persons);

System.out.println("Through the view:");

printPersons(unmodifiablePersons);

}

}