//
// simple partial example of reasonable object-oriented design
//      for an "address book" program, showing defining multiple classes
//      in a single source file.
//
import java.util.Hashtable ;

public class AddrBook {

        // an instance of this class represents an address book --
        //      a collection of records, each of which represents
        //      a combination of person's name, address, and phone
        //      number.  
        // we implement this using the Hashtable class.  we use
        //      the person's name as the key and define a class
        //      AddrBookEntry (below) to hold the remaining data
        //      (address and phone number).  we can then retrieve
        //      an entry by using the name as the key again.
        // other implementation choices are possible, for example
        //      one based on the Vector class.

        Hashtable book = new Hashtable() ;

        void add(String name, String addr, String phone) {
                book.put(name, new AddrBookEntry(name, addr, phone)) ;
        }
        AddrBookEntry lookup(String name) {
                return (AddrBookEntry) book.get(name) ;
        }
        public static void main(String[] args) {

                AddrBook myBook = new AddrBook() ;
                myBook.add("Me", "1234 Any Street, Sometown, FL", 
                        "(800) 555-1212") ;
                myBook.add("You", "12 Another Road, Sometown, FL",
                        "(888) 555-1212") ;

                AddrBookEntry e ;

                e = myBook.lookup("Me") ;
                System.out.println("Record for Me:  ") ;
                System.out.println("name = " + e.name) ;
                System.out.println("address = " + e.address) ;
                System.out.println("phone = " + e.phone) ;

                e = myBook.lookup("You") ;
                System.out.println("Record for You:  ") ;
                System.out.println("name = " + e.name) ;
                System.out.println("address = " + e.address) ;
                System.out.println("phone = " + e.phone) ;
        }
}

// second class definition -- only one public class per file allowed,
//      but additional non-public classes okay

class AddrBookEntry {

        // an instance of this class represents an address book
        //      entry (name, address, and phone number).  name
        //      is redundant if we use this class with the above
        //      implementation of AddrBook (because it's the same
        //      as the key used to store and retrieve records),
        //      but could be useful if we changed AddrBook to
        //      use, say, a vector instead.
        // note that we have access in AddrBook to the non-private
        //      fields and methods of this class.  they need not be
        //      public.

        String name ;
        String address ;
        String phone ;

        AddrBookEntry(String name, String address, String phone) {
                this.name = name ;
                this.address = address ;
                this.phone = phone ;
        }
}