ANSWER THIS JAVA BASED QUESTION, USING THE MOST SIMPLE WAY TO BETTER UNDERSTAND AND EXPLAIN EACH STEP: Question $4$

Aggregation Relationship:

A:

Part $1$:

I. Create a class Address with the following private fields:

$$ city

$$ street

$$ number

$$ postal$\_$code

II$.$ Add the following public methods for Address:

$$ A constructor that initializes all fields based on its parameters.

$$ Getter methods $($getCity$(),$ getStreet$(),$ etc.$)$ that return the values of the fields.

$$ Setter methods $($setCity$(),$ setStreet$(),$ etc.$)$ that update the field values based on the parameters.

$$ A display method that prints the full address on the screen.

III. Create a class Person with the following private fields:

$$ name

$$ surname

$$ year$\_$of$\_$birth $($constant$)$

$$ address $($of type Address$)$

IV$.$ Add the public methods for Person:

$$ A constructor that initializes all fields based on its parameters.

$$ Getter methods $($getName$(),$ getSurname$(),$ getYearOfBirth$(),$ etc.$)$ to return the values of the fields.

$$ Setter methods $($setName$(),$ setSurname$(),$ etc.$)$ to update the field values.

$$ A getAge method that calculates and returns the person's age based on the year$\_$of$\_$birth.

$$ Hint: Use Calendar.getInstance$().$get$($Calendar$.$YEAR$)$ to get the current year.

$$ An is$18$ method that returns true if the person is $18$ years old or older, and false otherwise.

$$ A changeAddress method that updates the person's address with new values passed as parameters.

$$ A display method that prints all the person$$s details on the screen, including their age and full

address.

Part $2$:

V$.$ Create a class Student with the following private fields:

$$ id $($constant$)$

$$ semester

$$ average

$$ person$\_$data $($constant$,$ type Person from part $1)$

VI$.$ The class contains the following public methods:

$$ A constructor that initializes all fields based on its parameters.

$$ Getter methods that return the values of the class fields.

$$ setSemester and setAverage methods that update the semester and average fields based on their

parameters.

$$ getYear method that calculates and returns the corresponding year of study based on the semester.

$$ checkAverage method that returns true if the average field is greater than the value passed as a

parameter, and false otherwise.

$$ Display method that prints all the student's data on the screen.

B:

Imagine we're designing a simple game. We need to represent a player that can wield a weapon. Using

aggregation, complete the following tasks:

I. Create a Weapon class with the following:

a$.$ A private field name for the weapon's name.

b$.$ A constructor that initializes the name field.

c$.$ A getter method getName$()$ that returns the name of the weapon.

II$.$ Create a Player class with the following:

a$.$ A private field name for the player's name.

b$.$ A private field weapon $($of type Weapon$)$ representing the weapon the player is wielding.

c$.$ A constructor that initializes both the name and weapon fields.

d$.$ A getter method getName$()$ that returns the player's name.

e$.$ A getter method getWeaponName$()$ that returns the name of the weapon the player is

wielding.

III. Create a Main class that:

a$.$ Creates a Weapon object $($e$.$g$.,$ a "Sword"$).$

b$.$ Creates a Player object and assigns the Weapon to them.

c$.$ Prints out the player's name and the name of the weapon they are wielding.