閱讀以下說(shuō)明和 Java 程序，填補(bǔ)代碼中的空缺，將解答填入答題紙的對(duì)應(yīng)欄內(nèi)。
【說(shuō)明】
以下 Jave 代碼實(shí)現(xiàn)一個(gè)簡(jiǎn)單客戶(hù)關(guān)系管理系統(tǒng)（CrM）中通過(guò)工廠（Customerrfactory ）對(duì)象來(lái)創(chuàng)建客戶(hù)（Customer）對(duì)象的功能?？蛻?hù)分為創(chuàng)建成功的客戶(hù)（realCustomer）和空客戶(hù)（NullCustomer）?？湛蛻?hù)對(duì)象是當(dāng)不滿足特定條件時(shí)創(chuàng)建或獲取的對(duì)象。類(lèi)間關(guān)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; ﹜
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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