Question

Modify the given Customer.java to implement the Comparable interface so that the customer will be sorted by their last name in ascending order. Implement a toString() method for the Customer class. Using the CustomerTester.java, add a least 5 new Customers to an ArrayList. Print the unsorted list. Sort the list of customers, and then print out the sorted ArrayList of Customers. Make sure your output is meaningful and readable. (21 points)

Submit Customer.java and CustomerTester.java.

Sample output:
Customer 1 is Tugg Thomson
Customer 2 is Fred Jones
Customer 3 is Sally Stevens
Customer 4 is Tim James
Customer 5 is George Thompson


Customer 1 is Tim James
Customer 2 is Fred Jones
Customer 3 is Sally Stevens
Customer 4 is George Thompson
Customer 5 is Tugg Thomson

Answer 1

As per question there is no Customer.java file given for modification and implement same.

Based on the question I understand the concept that what you’re looking for, and assuming the expected outcome based on sample output I have developed the following java code

Customer.java

class Customer implements Comparable<Customer>{ // implements the Comparable interface to Customer class

String first_name; //Declaring Customer first_name variable as a String

String last_name;   //Declaring Customer first_lastname variable as a String

Customer(String first_name,String last_name){ //Constructor for assigning variables

this.first_name=first_name;

this.last_name=last_name;

}

public int compareTo(Customer cust){ //compareTo() method will compare the Customer data

if(last_name.equals(cust.last_name)) //A conditional statement for equals of last_names

return 0; // If the conditional statement is true returns 0

else if(last_name.compareTo(cust.last_name)>0)

return 1;

else

return -1;

}

}

CustomerTester.java

import java.util.*; // import util classes

import java.io.*; // import IO classes

public class CustomerTester{ // class CustomerTester begins

public static void main(String[] args){ // declaring main method

int i=1, j=1; // an integers for printing customer serial number

ArrayList<Customer> al=new ArrayList<Customer>(); // al object creation

al.add(new Customer("Tugg","Thomson")); // adding customer data to ArrayList

al.add(new Customer("Fred","Jones"));

al.add(new Customer("Sally","Stevens"));

al.add(new Customer("Tim","James"));

al.add(new Customer("George","Thompson"));

System.out.println();

System.out.println("Before Sorting Last Name");

System.out.println();

for(Customer cust:al){ // loop for print before sorting data

System.out.println("Customer "+i+" is "+cust.first_name+" "+cust.last_name);

    i++;

}

System.out.println();

System.out.println("After Sorting Last Name");

System.out.println();

Collections.sort(al);

for(Customer cust:al){   // loop for print after sorting data

System.out.println("Customer "+j+" is "+cust.first_name+" "+cust.last_name);

    j++;

}

}

}

Output (Screenshot): The following screenshot also guide you how to compile and execute the code for output

.Administrator: C:\Windowslsystem321cmd.exe C:NUsers Shiva\Desktop java>javac Customer.java C:NUsers Shiva\Desktop java>javac CustomerTester.java C:NUsers Shiva\Desktop java>java CustomerTester Before Sorting Last Name Customer Customer Customer Customer Customer 5 is George Thompson 1 is Tugg Thomson 2 is Fred Jones 3 is Sally Stevens 4 is Tim James After Sorting Last Name Customer 1 is Tim Janes istomer 2 is Fred Jones Customer Customer 4 is George Thompson Customer 3 is Sally Stevens 5 is Tugg Thomson C:NUsers Shiva \Desktop java