Question

I have a class named Person.This class represents (as the name says) a Person. Now I have to create a class PhoneBook to represent a list of Persons. How can I do this? I don’t understand what means “create a class to represent a list”.

import java.util.*;

public class Person {

private String surname;
private String name;
private String title;
private String mail_addr;
private String company;
private String position;

private int homephone;       
private int officephone;      
private int cellphone;       

private Collection<OtherPhoneBook> otherphonebooklist;

public Person(String surname,String name,String title,String mail_addr,String company,String position){

    this.surname=surname;
    this.name=name;
    this.title=title;
    this.mail_addr=mail_addr;
    this.company=company;
    this.position=position;

    otherphonebooklist=new ArrayList<OtherPhoneBook>();

}

public String getSurname(){

    return surname;
}

public String getName(){

    return name;
}

public String getTitle(){

    return title;
}

public String getMailAddr(){

    return company;
}

public String getCompany(){

    return position;
}

public void setHomePhone(int hp){

    homephone=hp;
}

public void setOfficePhone(int op){

    officephone=op; 
}

public void setCellPhone(int cp){

    cellphone=cp;
}

public int getHomePhone(){

    return homephone;
}

public int getOfficePhone(){

    return officephone;
}

public int getCellPhone(){

    return cellphone;
}

public Collection<OtherPhoneBook> getOtherPhoneBook(){

    return otherphonebooklist;
}

public String toString(){

    String temp="";

    temp+="\nSurname: "+surname;
    temp+="\nName: "+name;
    temp+="\nTitle: "+title;
    temp+="\nMail Address: "+mail_addr;
    temp+="\nCompany: "+company;
    temp+="\nPosition: "+position;

    return temp;

}
}

Answer 1

Based on the class being named PhoneBook, I assume that you ultimately want to create a mapping between a phone number, and a person. If this is what you need to do then your PhoneBook class should contain a Map instead of a List (but this may depend on other parameters of the project).

public class PhoneBook
{
    private Map<String,Person> people = new HashMap<String,Person>();

    public void addPerson(String phoneNumber, Person person)
    {
        people.put(phoneNumber,person);
    }

    public void getPerson(String phoneNumber)
    {
        return people.get(phoneNumber);
    }
}

In the above, the phone number is represented as a String, which is probably not ideal since the same phone number could have different String representations (different spacing, or dashes, etc). Ideally the Map key would be a PhoneNumber class that takes this all into account in its hashCode and equals functions.