Question

Using JAVA*
Design a class named Person with fields for holding a person’s name,
address, and telephone number. Write one or more constructors and the
appropriate mutator and accessor methods for the class’s fields.

Next, design a class named Customer, which extends the Person class. The
Customer class should have a field for a customer number and a boolean
field indicating whether the customer wishes to be on a mailing list. Write
one or more constructors and the appropriate mutator and accessor methods
for the class’s fields. Demonstrate an object of the Customer class in a simple
program.

1) Add an "age" field to the Person class with appropriate methods to get and set the age.

2) Add an interface (you can call it what you want but a good suggestion would be "AgeCalculator") this will have a calculate method that takes 2 parameters.

3) Create a Lambda Expression with 2 Parameters (not just 1 as we did for the quickcheck) .... you will be calling yours with 2 parameters -- the person's current age which is stored in the Person/Customer object and how many years you want to add to that person's age .

Example : ask the user how many years they want to add to the person's age and say you store it in a variable called futureAge ; assuming you defined your multiple parameter lambda expression (let's say you called it future) and your AgeCalculator interface, you could calculate the future age by saying:

future.calculate(curAge, numYearsAdded) (see page 688 for 1 parameter lambda expression call)

Answer 1

public class Person {
   private String name;
   private String address;
   private long telephoneNumber;
   private int age;
   public Person() {
       this.name="";
       this.address="";
       this.telephoneNumber=0;
       this.age=0;
   }
   public Person(String name,String address,long phn,int age){
       this.name=name;
       this.address=address;
       this.telephoneNumber=phn;
       this.age=age;
              
   }
   public String getName() {
       return name;
   }
   public void setName(String name) {
       this.name = name;
   }
   public String getAddress() {
       return address;
   }
   public void setAddress(String address) {
       this.address = address;
   }
   public long getTelephoneNumber() {
       return telephoneNumber;
   }
   public void setTelephoneNumber(long telephoneNumber) {
       this.telephoneNumber = telephoneNumber;
   }
   public int getAge() {
       return age;
   }
   public void setAge(int age) {
       this.age = age;
   }
}

public class Customer extends Person{
   private String customeNumber;
   private boolean isOnMailingList;
   public Customer() {
       this.customeNumber="";
       this.isOnMailingList=false;
   }
   public Customer(String name,String address,long phn,int age,String custNo,
           boolean isMailingOn){
       super(name, address, phn, age);
       this.customeNumber=custNo;
       this.isOnMailingList=isMailingOn;
   }
   public String getCustomeNumber() {
       return customeNumber;
   }
   public void setCustomeNumber(String customeNumber) {
       this.customeNumber = customeNumber;
   }
   public boolean isOnMailingList() {
       return isOnMailingList;
   }
   public void setOnMailingList(boolean isOnMailingList) {
       this.isOnMailingList = isOnMailingList;
   }
  
}

public interface AgeCalculator {
   void calculate(int param1,int param2);
}

import java.util.Scanner;

public class TestCustomer {

   public static void main(String[] args) {
       Customer cust=new Customer("john", "12-street,LA", 95867263,
               25, "CUS123", true);
       Scanner sc=new Scanner(System.in);
       System.out.println("Enter no of years to add to person age: ");
       int noOfYears=sc.nextInt();
       System.out.println("Age before calculate: "+cust.getAge());
       AgeCalculator future=(int currAge,int yearsToAdd)->{//lambda function displays future age
           int futureAge= currAge+yearsToAdd;
           System.out.println("Future age is: "+futureAge);
       };
       future.calculate(cust.getAge(), noOfYears);//calling lambda calculate method
      
      
   }

}

Expected output:

Enter no of years to add to person age: 5 Age before calculate: 25 Age after calculate: 30