阅读以下说明和 Java 程序,填补代码中的空缺,将解答填入答题纸的对应栏内。
【说明】
以下 Jave 代码实现一个简单客户关系管理系统(CrM)中通过工厂(Customerrfactory )对象来创建客户(Customer)对象的功能。客户分为创建成功的客户(realCustomer)和空客户(NullCustomer)。空客户对象是当不满足特定条件时创建或获取的对象。类间关系如图 5-1 所示。
【Java 代码】
Abstract class Customer﹛
Protected String name;
()boolean isNil()
()String getName();
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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; ﹜
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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);
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return ()
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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());
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Public static viod main (String[]arge)﹛
CrM crm =new CrM();
Crm,getCustomer();
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/*程序输出为:
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();
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/*程序输出为:
Customer
rob
Not Available ini Customer Database
Julie
Not Available in Customer Database