PhonebookHashtable

import java.io.*;
import java.util.*;

public class Main {

private Hashtable phoneBooks;

public Main(){
 this.phoneBooks = new Hashtable();
 }



public void tambah(String name, String number){
 if(this.phoneBooks.containsKey(name)){
 System.out.println(name+ " exists.");
 } else {
 this.phoneBooks.put(name, number);
 System.out.println(name+" success.");
 }
 }

public void cari (String name){
 if(this.phoneBooks.containsKey(name)){
 String number = (String) this.phoneBooks.get(name);
 System.out.println(name+"'s number is "+number+".");
 } else {
 System.out.println("Unknown '"+name+"'");
 }
 }

public void status(){
 Enumeration names;
 names = this.phoneBooks.keys();
 int total = 0;
 while(names.hasMoreElements()) {
 String str = (String) names.nextElement();
 System.out.println(str + " " + this.phoneBooks.get(str));
 total++;
 }
 System.out.println("Total "+total+" kontak.");
 }

public void hapus_entry(String name){
 if(this.phoneBooks.containsKey(name)){
 this.phoneBooks.remove(name);
 System.out.println(name+" deleted.");
 } else {
 System.out.println("Unknown'"+name+"'");
 }
 }

public static void main(String[] args ) throws IOException {

Scanner scanner = new Scanner(System.in);
Main phoneBook = new Main();

while(true){
    System.out.print("Choose category\n");
    System.out.print("1. Add contact \n");
    System.out.print("2. Search contact \n");
    System.out.print("3. Status \n");
    System.out.print("4. Delete contact \n");
    System.out.print("5. Exit \n");
    System.out.print("Command: ");

int command = scanner.nextInt();

if(command==1){
    System.out.print("Name: ");
    String name = scanner.next();
    System.out.print("Number: ");
    String number = scanner.next();
    phoneBook.tambah(name, number);
 }
 else if(command==2){
    System.out.print("Name: ");
    String name = scanner.next();
    phoneBook.cari(name);
 }
 else if(command==3){
    phoneBook.status();
 }
 else if(command==4){
    System.out.print("Name: ");
    String name = scanner.next();
    phoneBook.hapus_entry(name);
 }
 else if(command==5){
 break;
 }
 }
 scanner.close();
 }
 }