閱讀以下說明和 Java程序，填補代碼中的空缺，將解答填入答題紙的對應欄內(nèi)。
【說明】
以下Java代碼實現(xiàn)一個簡單客戶關系管理系統(tǒng)（CRM）中通過工廠（CustomerFactory ）對象來創(chuàng)建客戶（Customer）對象的功能?？蛻舴譃閯?chuàng)建成功的客戶（RealCustomer）和空客戶 （NullCustomer）?？湛蛻魧ο笫钱敳粷M足特定條件時創(chuàng)建或獲取的對象。類間關系如圖 5-1 所示。

圖5-1 類圖
【Java代碼】
Abstract class Customer﹛
Protected String name;
（  1  ）boolean isNil();
（  2  ）String getName();
﹜
Class RealCustomer （   3   ）Customer{
Public RealCustomer(String name){  this.name=name;   }
Public String getName(){   return name ;   }
Public boolean is Nil() {   return false;   }
﹜

Class NullCustomer（ 4  ）Customer﹛
Public String getName()﹛   return "Not Available in Customer Database";   ﹜
Public boolean isNil() ﹛    return true;    ﹜
﹜
class Customerfactory {
public String[] names = {"Rob"，"Joe"，"Julie"};
public Customer getCustomer(String name) {
for (int i = 0; i < names.length;i++) {
if (names[i].（   5   ）)﹛
return new RealCustomer(name);
﹜
﹜
return （   6   ）;
﹜
﹜
Public class CrM﹛
Public viod get Customer()﹛
Customerfactory（  7   ）;
Customer customer1-cf.getCustomer("Rob");
Customer customer2=cf.getCustomer("Bob");
Customer customer3= cf.getCustomer("Julie");
Customer customer4= cf.getCustomer("Laura");
System.out.println("customers”)
System.out.println(customer1.getName());
System.out.println(customer2getName());
System.out.println(customer3.getName());
System.out.println(customer4.getName());
﹜
Public static viod main (String[]arge)﹛
CRM crm =new CRM();
Crm.getCustomer();
﹜
﹜
/*程序輸出為：
Customers
rob
Not Available in Customer Database
Julie
Not Available in Customer Database
*/