西北工業大學·面向物件編程實驗三
3.1
題目說明：給定Project類，在ProjectArray中實作缺失功能，并在測驗類TestProjectArray中運行成功顯示“All tests passed”（具體說明，見文章末尾Unit3-1檔案）
public class ProjectArray {
/**
* Creates an array with three objects of class {@link Project}.
* <p>
* The first element of the array is the object
* <code>first</code>, the second element of the array is
* the object <code>second</code>, and the third element of the
* array is the object <code>third</code>.
* </p>
*
* @param first a {@link Project} object.
* @param second a {@link Project} object.
* @param third a {@link Project} object.
* @return an array with the objects <code>first</code>,
* <code>second</code>, and <code>third</code>.
*/
public static Project[] makeArray(Project first, Project second,
Project third) {
if(first!=null&&second!=null&&third!=null) {
Project[] project=new Project[3];
project[0]=first;
project[1]=second;
project[2]=third;
return project;
}else {
return null; // REMOVE; USED SO THIS FILE COMPILES
}
}
/**
* Creates a new array from the specified array of {@link Project}
* objects.
* <p>
* The elements in the new array have the same order as those in
* the specified array.
* </p>
*
* @param array an array that contains objects of class {@link Project}.
* @return a <i>new</i> array of the objects in the specified array.
*/
public static Project[] copyArray(Project[] array) {
if(array!=null) {
Project[] project=new Project[array.length];
for(int i=0;i<array.length;i++) {
/*Project temproject = new Project(array[i].getId(),array[i].getName(),array[i].getPrice());
project[i]= project;*/
project[i]=array[i];
}
return project;
}else {
return null;
}
}
/**
* Returns the {@link Project} object with the specified ID.
*
* @param array an array that contains objects of class {@link Project}.
* @param id an Project ID.
* @return The {@link Project} object with the specifed
* ID. Returns <code>null</code> if there are no Projects
* in the specified array with the specifed ID.
*/
public static Project getProject(Project[] array, int id) {
if(array.length==0) {
return null;
}else {
for(Project project : array) {
if(project.getId()==id) {
return project;
}
}
return null;
}
}
/**
* Returns the number of Projects whose price is Lower than the specified
* dollar amount.
*
* @param array an array that contains objects of class {@link Project}.
* @param amount a dollar amount.
* @return the number of Projects whose price is Lower than the
* specified dollar amount.
*/
public static int countLowerPrice(Project[] array, double amount) {
if(array.length==0||amount==0) {
return 0; // REMOVE; USED SO THIS FILE COMPILES
}else {
int num=0;
for(Project project : array) {
if(project.getPrice()<amount) {
num++;
}
}
return num;
}
}
/**
* Returns the sum of the price of the Projects in the specified
* array.
*
* @param array an array that contains objects of class {@link Project}.
* @return the sum of the price of the Projects in the specified
* array.
*/
// for-each loop
public static double sumPrice(Project[] array) {
if(array.length==0) {
return 0; // REMOVE; USED SO THIS FILE COMPILES
}else {
double sumprice=0;
for(Project project : array) {
sumprice=sumprice+project.getPrice();
}
return sumprice;
}
}
/**
* Obtains the Lowest price in the specified array.
*
* @param array an array that contains objects of class {@link Project}.
* @return the Lowest price in the specified array.
*/
// for-each loop
public static double getLowestPrice(Project[] array) {
if(array.length==0) {
return 0; // REMOVE; USED SO THIS FILE COMPILES
}else {
double low=array[0].getPrice();
for(Project project : array) {
if(low>project.getPrice()) {
low=project.getPrice();
}
}
return low;
}
}
/**
* Increases the Price of every Project in the specified array by the
* specified amount.
*
* @param array an array that contains objects of class {@link Project}.
*/
// for-each loop
public static void increaseAll(Project[] array, double amount) {
for(Project project : array) {
double price = project.getPrice();
project.setPrice(price+amount);
}
}
/**
* Returns a string representation of the specified
* {@link Project} array.
* <p>
* Uses the method <code>toString</code> in class <code>Project</code>
* to obtain the string representation of each object in the array.
* </p>
* A new line character ( \n ) separates the string representations
* of each <code>Project</code> object. For example:
* </p>
* <pre>
* Project[102,cruise,68250.0]\n
* Project[101,domestic,36000.0]\n
* Project[103,outbound,92175.0]
* </pre>
* <p>
* Note that the string returned does <i>not</i> end with a new line
* character (\n).
* </p>
* <p>
* This method assumes that every element in the specified array
* contains a valid reference to an <code>Project</code> object.
* </p>
*
* @param array an array that contains objects of class {@link Project}.
* @return the string representation of the specified array
*/
public static String displayAll(Project[] array) {
String string="";
for(Project project : array) {
string = string + project.toString();
if(!project.equals(array[array.length-1])) {
string=string + "\n";
}
}
return string;
}
}
3.2.1
題目說明：在這個題目中你將實作復試系統，該系統向用戶提供四種選擇：
根據用戶選擇，系統能夠以純文本、HTML或XML三種格式顯示學生資訊，
復試系統的部分類圖如下：
你需要實作介面 StudentsFormatter 、類 FushiSystem 、類 PlainTextStudentsFormatter 、類 HTMLStudentsFormatter 和類 XMLStudentsFormatter ，請按照類圖和下面的描述資訊實作復試系統，部分代碼已經實作，在 FushiSystem 檔案夾中，這些類無需更改，你需要使用單例模式和策略模式來實作復試系統顯示學生資訊的代碼，
代碼如下（單一實體模型采用懶漢式）：
1.StudentsFormatter介面：
public interface StudentsFormatter {
/**
* @param studentCatalog 創建介面方法的形式引數
*
* @return 介面方法回傳String物件
*/
String formatStudents(StudentCatalog studentCatalog);
}
2.PlainTextStudentsFormatter類：
public class PlainTextStudentsFormatter implements StudentsFormatter{
/**
* singletonInstance 作為呼叫formatStudents方法的通道
*/
private static PlainTextStudentsFormatter singletonInstance=null;
/**
* singletonInstance的無參構造方法
*/
private PlainTextStudentsFormatter(){
}
/**
* @param studentCatalog 創建介面方法的形式引數
*
* @return s 回傳輸出字串
*/
@Override
public String formatStudents(StudentCatalog studentCatalog) {
String s="\nStudent Catalog\n";
for(Student student : studentCatalog.students){
s=s+student.getId()+"_";
s=s+student.getName()+"_";
for(TestItem testitem : student.getExamPaper().testitem){
s=s+testitem.getTest().getCode();
if(!testitem.equals(student.getExamPaper().getTestItem(9))){
s=s+"_";
}
}
s=s+"\n";
}
return s;
}
/**
* @return singletonInstance 當singletonInstance為空時創建并回傳
*/
public static PlainTextStudentsFormatter getSingletonInstance() {
if(singletonInstance==null){
singletonInstance=new PlainTextStudentsFormatter();
}
return singletonInstance;
}
}
輸出樣例：
Student Catalog
201921300_吳廣勝_E004_P008_E001_M003_M001_P004_M008_P005_P007_E003
2019213002_陳盛典_E008_M007_P002_M002_E007_P007_P006_E009_P003_M010
2019213003_劉子豪_M004_P002_P009_P007_M007_E005_M003_E006_P001_E002
2019213004_仇歷_P004_P007_M004_P002_E003_E007_P009_M006_M001_E004
2019213005_鄭西澤_P005_E007_P004_E004_P007_M006_M004_E009_P009_M001
3.HTMLStudentsFormatter類：
public class HTMLStudentsFormatter implements StudentsFormatter{
/**
* singletonInstance 作為呼叫formatStudents方法的通道
*/
private static HTMLStudentsFormatter singletonInstance=null;
/**
* singletonInstance的無參構造方法
*/
public HTMLStudentsFormatter(){
}
/**
* @param studentCatalog 傳入一個需要輸出資訊的學生串列
*
* @return s 回傳輸出字串
*/
@Override
public String formatStudents(StudentCatalog studentCatalog) {
String s="\n<html>\n";
s=s+" <body>\n";
s=s+" <center><h2>學生目錄</h2></center>\n";
for(Student student : studentCatalog.students){
s=s+" <hr>\n";
s=s+" <h4>"+student.getId()+" "+student.getName()+"</h4>\n";
s=s+" <blockquote>\n";
for(TestItem testitem : student.getExamPaper().testitem){
s=s+" "+"<"+testitem.test.getCode()+"> <"+testitem.getTest().getTitle()+"> <br>\n";
}
s=s+" </blockquote>\n";
}
s=s+" </body>\n";
s=s+"</html>";
return s;
}
/**
* @return singletonInstance 當singletonInstance為空時創建物件
*/
public static HTMLStudentsFormatter getSingletonInstance() {
if(singletonInstance==null){
singletonInstance=new HTMLStudentsFormatter();
}
return singletonInstance;
}
}
輸出樣例：
4.XMLStudentsFormatter類
public class XMLStudentsFormatter implements StudentsFormatter{
/**
* singletonInstance 作為呼叫formatStudents方法的通道
*/
private static XMLStudentsFormatter singletonInstance=null;
/**
* singletonInstance無參構造方法
*/
public XMLStudentsFormatter() {
}
/**
* @param studentCatalog 創建介面方法的形式引數
*
* @return s 回傳輸出字串
*/
@Override
public String formatStudents(StudentCatalog studentCatalog) {
String s="\n";
s=s+"<StudentCatalog>\n";
for(Student student : studentCatalog.students){
s=s+" <student id=\"<"+student.getId()+">\" name=\"<"+student.getName()+">\">\n";
s=s+" <ExamPaper>\n";
for(TestItem testitem : student.getExamPaper().testitem){
s=s+" <Test code=\"<"+testitem.getTest().getCode()+">\"><"+testitem.getTest().getTitle()+"></Test>\n";
}
s=s+" </ExamPaper>\n";
s=s+" </Student>\n";
}
return s;
}
/**
* @return singletonInstance 當singletonInstance為空時創建并回傳
*/
public static XMLStudentsFormatter getSingletonInstance() {
if(singletonInstance==null){
singletonInstance=new XMLStudentsFormatter();
}
return singletonInstance;
}
}
輸出樣例：
3.2.2
使用工廠模式實作3.2.1的輸出，我利用的使抽象類實作簡單工廠模式
代碼如下：
1.StudentsFormatter抽象類
public abstract class StudentsFormatter {
/**
* @param studentCatalog 創建抽象方法的形式引數
*
* @return 抽象方法回傳String物件
*/
abstract String formatStudents(StudentCatalog studentCatalog);
}
2.Factory類
public class Factory {
public StudentsFormatter createFormatter(int operate){
StudentsFormatter studentsFormatter=null;
switch(operate){
case 0:
studentsFormatter=PlainTextStudentsFormatter.getSingletonInstance ();
case 1:
studentsFormatter=HTMLStudentsFormatter.getSingletonInstance ();
case 2:
studentsFormatter=XMLStudentsFormatter.getSingletonInstance ();
}
return studentsFormatter;
}
}
然后將fushiSystem中的run函式對應部分改成如下圖所示：
實驗結束！！
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