public class PhoneEntry
{
    private String first;
    private String last;
    private String phone;
    private String email;
    
    /* PRE:  'first' and 'last' can not both be the empty string, and
     *       no String should be null
     * POST: Stores input values in class fields.
     */
    public PhoneEntry(String first, String last, String phone, String email)
    {
        this.first = first;
        this.last = last;
        this.phone = phone;
        this.email = email;
    }

    /* PRE:  a valid PhoneEntry (where not both 'first' and 'last' can be 
     *       empty at the same time.
     * POST: Phone entries will be compared as follows:
     *          * if both have first and last name not empty, compare 
     *            the strings "last, first"
     *          * if both have first names empty, compare last names
     *          * if both have last names empty, compare first names
     *          * an entry with first name only is considered smaller than
     *            an entry with both first and last name
     */
    
    // THIS CODE BELOW DOES NOT WORK AS SPECIFIED IN 'POST' !!! Change it!
    public int compareToIgnoreCase(PhoneEntry e)
    {
        if ((last.equals("")) || (e.last.equals("")))
        {
            return first.compareToIgnoreCase(e.first);
        }
        else
        {
            return last.compareToIgnoreCase(e.last);
        }
    }
    public String getFirst()
    {
        return first;
    }
    
    public String getLast()
    {
        return last;
    }
    
    public String getPhone()
    {
        return phone;
    }
    
    public String getEmail()
    {
        return email;
    }
    
    public String toString()
    {
        if (last.equals(""))
            return first;
        else if (first.equals(""))
            return last;
        else
            return last + ", " + first;
    }
}