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 Jave 代碼實現(xiàn)一個簡單客戶關系管理系統(tǒng)(CrM)中通過工廠(Customerrfactory )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。
【Java 代碼】
Abstract class Customer﹛
Protected String name;
()boolean isNil()
()String getName();
﹜
Class realCustomer ()Customer﹛
Public realCustomer(String name )﹛ return false; ﹜
﹜
Class NullCustomer()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].())﹛
return new realCusωmer(name);
﹜
﹜
return ()
﹜
﹜
Public class CrM﹛
Public viod get Customer()﹛
Customerfactory()
Customer customer1-cf.getCustomer(″rob″);
Customer customer2=cf.getCustomer(″rob″);
Customer customer3= cf.getCustomer(″Julie″);
Customer customer4= cf.getCustomer(″Laura″);
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:
Customer
rob
Not Available in Customer Database
Julie
Not Available in Customer Datable
*/
int main()﹛
CrM*crs=newCrM();
Crs->getCustomer();
Crs->getCustomer();
Delete crs;
return();
﹜
/*程序輸出為:
Customer
rob
Not Available ini Customer Database
Julie
Not Available in Customer Database