Question

Create a simple Java class for a Month object with the following requirements:

 This program will have a header block comment with your name, the course and section, as well as a brief description of what the class does.
 All methods will have comments concerning their purpose, their inputs, and their outputs
 One integer property: monthNumber (protected to only allow values 1-12). This is a numeric representation of the month (e.g. 1 represents January, 2 represents February, etc.)
 A constructor that takes no arguments, and sets the monthNumber to 1.
 Add a second constructor that takes in an integer argument to set the initial monthNumber for the new Month object. Use data protection to prevent the user from entering a number less than 1 or greater than 12. When a non-valid input is entered, throw a new IllegalArgumentException.
 A setMonth() method that takes an integer and uses data protection to prevent the user from entering a number less than 1 or greater than 12. Also throw an IllegalArgumentException if an illegal value is entered.
 A getMonth() method that returns the monthNumber as an integer.
 Add a String array property that holds the values of the month names (e.g. monthNames[3] would hold the value “March”). Remember, you can leave the 0th index blank/null
 Add a toString() method to use the monthNumber property to return the name of the month as a String. Use the private global String array with the names of the months in it to return the proper String based on the monthNumber.
 Add an equals() method that takes in a month object and returns a boolean based on the values of each object’s monthNumber
 Add a compareTo() method that takes in a month object and returns a negative number if the called object is smaller than the passed in object, a positive number if the called object is bigger than the passed in object, and zero (0) if the two objects are equivalent.

Create a simple program using Java that demonstrates the month object with the following requirements:

 That creates a month object using the no argument constructor.
 A second month object is created using the constructor that takes in an integer argument.
 Additionally, use either a do or while loop to get the user to enter a number between 1 and 12 using the setMonth() method on the 1st month object. The loop will continue until they enter a valid number.
 The program will display the month number for both of the objects using the getMonth() method.

Answer 1

Following is the answer:

Months.java

public class Months {
    private int monthNumber;
    private String[] monthNames = {"null", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};

    //constructor with no arguments
    Months(){
        this.monthNumber = 1;
    }

    //constructor with one argument monthNumber
    Months(int monthNumber){
        //exception if monthNumber is > 13 and < 0
        try {
            if(monthNumber > 0 && monthNumber < 13){
                this.monthNumber = monthNumber;
            }else {
                throw new IllegalArgumentException();
            }
        }catch (IllegalArgumentException e){
            System.out.println("Invalid month");
        }
    }

    //get method to return monthNumber
    public int getMonthNumber() {
        return monthNumber;
    }

    //set method to set monthNumber
    public void setMonthNumber(int monthNumber) {
        try {
            if(monthNumber > 0 && monthNumber < 13){
                this.monthNumber = monthNumber;
            }else {
                throw new IllegalArgumentException();
            }
        }catch (IllegalArgumentException e){
            System.out.println("Invalid month");
        }
    }
    
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Months months = (Months) o;
        return monthNumber == months.monthNumber;
    }

    public int compareTo(Object o){
        return this.compareTo(o);
    }

}

MonthsMain.java

import java.util.Scanner;

public class MonthsMain {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        Months month1 = new Months();
        Months months = new Months(12);
        int month;
        do{
            System.out.println("Enter a month (between 1-12)");
            month = sc.nextInt();
        }while (month < 1  || month > 12);
        month1.setMonthNumber(month);
        System.out.println("Month1: " + month1.getMonthNumber());
        System.out.println("Month1: " + months.getMonthNumber());
    }
}

Output: