我又來了,大佬們別複製,必錯(狗頭)
打擊不誠信行爲,從每個HITer做起,鄙視代寫+抄襲+伸手黨
希望同學建議,是不是該刪點代碼?
本項目計劃於5.19日實驗課驗收
更新中
如果有所參考 請點點關注 點點贊GitHub Follow一下謝謝
2020春計算機學院《軟件構造》課程Lab4實驗報告
- Software Construction 2020 Spring
- Lab-4 Debugging, Exception Handling, and Defensive Programming
- 版權聲明:
1183710109 郭茁寧
文章目錄
- 我又來了,大佬們別複製,必錯(狗頭)
- 打擊不誠信行爲,從每個HITer做起,*鄙視代寫+抄襲+伸手黨*
- 希望同學建議,是不是該刪點代碼?
- 本項目計劃於5.19日實驗課驗收
- `更新中`
- 如果有所參考 請點點關注 點點贊[GitHub Follow一下謝謝](https://github.com/gzn00417)
- 2020春計算機學院《軟件構造》課程Lab4實驗報告
- 1 實驗目標概述
- 2 實驗環境配置
- 3 實驗過程
- 3.1 Error and Exception Handling
- 3.1.1 處理輸入文本中的三類錯誤
- 3.1.1.1 DataPatternException
- 3.1.1.2 EntryNumberFormatException
- 3.1.1.3 SameAirportException
- 3.1.1.4 TimeOrderException
- 3.1.1.5 PlaneNumberFormatException
- 3.1.1.6 PlaneTypeException
- 3.1.1.7 PlaneSeatRangeException
- 3.1.1.8 PlaneAgeFormatException
- 3.1.1.9 SameEntryException
- 3.1.1.10 HugeTimeGapException
- 3.1.1.11 EntryInconsistentInfoException
- 3.1.1.12 PlaneInconsistentInfoException
- 3.1.1.13 SameEntrySameDayException
- 3.1.2 處理客戶端操作時產生的異常
- 3.2 Assertion and Defensive Programming
- 3.3 Logging
1 實驗目標概述
略
2 實驗環境配置
略
3 實驗過程
3.1 Error and Exception Handling
在data/Exceptions/中構造了錯誤數據,並在ExceptionTest.java
中測試了這些錯誤。
3.1.1 處理輸入文本中的三類錯誤
第1-8個爲不符合語法規則錯誤,第9個爲元素相同錯誤,第10-13個爲依賴關係不正確錯誤。
處理方法爲:
try {
……
throw new ……Exception();
} catch (……Exception e1) {
logger.log(Level.WARNING, e1.getMessage(), e1);
……
}
3.1.1.1 DataPatternException
原因:由於數據的常量錯誤而沒有匹配到單個元素。
拋出異常方法:在正則表達式匹配時,若沒有匹配到則拋出該錯誤。
if (!matcher.find()) {
throw new DataPatternException("Data: " + stringInfo + " mismatch Pattern.");
}
3.1.1.2 EntryNumberFormatException
原因:計劃項編號不符合規則。
拋出異常方法:檢查是否符合“前兩個字符爲大寫字母,後2-4個字符爲數字”。
/**
* check entry number
* @param planningEntryNumber
* @throws EntryNumberFormatException
*/
public static void checkEntryNumber(String planningEntryNumber) throws EntryNumberFormatException {
if (Character.isUpperCase(planningEntryNumber.charAt(0))
&& Character.isUpperCase(planningEntryNumber.charAt(1))) {
for (int i = 2; i < planningEntryNumber.length(); i++) {
if (!Character.isDigit(planningEntryNumber.charAt(i)))
throw new EntryNumberFormatException(planningEntryNumber + " has incorrect format.");
}
} else
throw new EntryNumberFormatException(planningEntryNumber + " has incorrect format.");
}
3.1.1.3 SameAirportException
原因:起飛和到達機場相同引起的錯誤。
拋出異常方法:對比兩個機場字符串是否相等。
/**
* check airports are different
* @param departureAirport
* @param arrivalAirport
* @throws SameAirportException
*/
public static void checkDiffAirport(String departureAirport, String arrivalAirport) throws SameAirportException {
if (departureAirport.equals(arrivalAirport))
throw new SameAirportException(departureAirport + " is the same with " + arrivalAirport + " .");
}
3.1.1.4 TimeOrderException
原因:起飛時間應該在到達時間之前(不能相等)。
拋出異常方法:首先try時間能否被parse,若不行則拋出DateTimeParseException;否則在finally中使用LocalDateTime.isBefore()方法比較時間先後。
/**
* check time format and departure is before arrival
* @param departureTime
* @param arrivalTime
* @throws TimeOrderException
* @throws DateTimeParseException
*/
public static void checkTime(String departureTime, String arrivalTime)
throws TimeOrderException, DateTimeParseException {
LocalDateTime dt = null, at = null;
try {
dt = LocalDateTime.parse(departureTime, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
at = LocalDateTime.parse(arrivalTime, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm"));
} catch (Exception e) {
throw new DateTimeParseException("The date time is not matched.", departureTime + arrivalTime, 0);
} finally {
if (dt != null && at != null) {
if (!dt.isBefore(at))
throw new TimeOrderException(
"Departure time " + departureTime + " is not before arrival time " + arrivalTime + " .");
}
}
}
3.1.1.5 PlaneNumberFormatException
原因:飛機編號不符合格式。
拋出異常方法:檢查字符串長度以及首字母、後4位數字。
/**
* check plane number
* @param planeNumber
* @throws PlaneNumberFormatException
*/
public static void checkPlaneNumber(String planeNumber) throws PlaneNumberFormatException {
if (planeNumber.length() == 5 && (planeNumber.charAt(0) == 'N' || planeNumber.charAt(0) == 'B')) {
for (int i = 1; i < planeNumber.length(); i++) {
if (!Character.isDigit(planeNumber.charAt(i)))
throw new PlaneNumberFormatException(planeNumber + " has incorrect format.");
}
} else
throw new PlaneNumberFormatException(planeNumber + " has incorrect format.");
}
3.1.1.6 PlaneTypeException
原因:飛機類型不符合格式。
拋出異常方法:檢查是否由字母和數字構成。
/**
* check plane type
* @param strType
* @throws PlaneTypeException
*/
public static void checkPlaneType(String strType) throws PlaneTypeException {
for (int i = 0; i < strType.length(); i++) {
char ch = strType.charAt(i);
if (!(Character.isAlphabetic(ch) || Character.isDigit(ch)))
throw new PlaneTypeException(strType + " has incorrect format.");
}
}
3.1.1.7 PlaneSeatRangeException
原因:飛機座位數範圍錯誤。
拋出異常方法:轉換爲整數比較範圍。
/**
* check plane seat range
* @param strSeats
* @throws PlaneSeatRangeException
*/
public static void checkPlaneSeat(String strSeats) throws PlaneSeatRangeException {
int intSeats = Integer.valueOf(strSeats);
if (intSeats < 50 || intSeats > 600)
throw new PlaneSeatRangeException(intSeats + " is not in [50, 600].");
}
3.1.1.8 PlaneAgeFormatException
原因:飛機年齡非一位小數或整數,且介於0-30之間
拋出異常方法:查找小數點的位置,與字符串長度比較,得出幾位小數,並查找區間。
/**
* check plane age format
* @param strAge
* @throws PlaneAgeFormatException
*/
public static void checkPlaneAge(String strAge) throws PlaneAgeFormatException {
double age = Double.valueOf(strAge);
if (strAge.indexOf(".") < strAge.length() - 2 || age < 0 || age > 30)
throw new PlaneAgeFormatException();
}
3.1.1.9 SameEntryException
原因:存在兩個航班,飛機和航班號都相等。
拋出異常方法:遍歷所有計劃項,兩兩比較是否存在上述條件。
/**
* check dates and numbers conflict
* @throws SameEntryException
*/
public void checkDateNumberConflict() throws SameEntryException {
List<PlanningEntry<Resource>> entries = this.getAllPlanningEntries();
int n = entries.size();
for (int i = 0; i < n - 1; i++) {
for (int j = i + 1; j < n; j++) {
if (i != j) {
PlanningEntry<Resource> e1 = entries.get(i), e2 = entries.get(j);
if (e1.getPlanningEntryNumber().equals(e2.getPlanningEntryNumber())) {
if (((FlightSchedule<Resource>) e1).getResource()
.equals(((FlightSchedule<Resource>) e2).getResource()))
throw new SameEntryException(e1.getPlanningEntryNumber() + " and "
+ e2.getPlanningEntryNumber() + " are the same entries.");
}
}
}
}
}
3.1.1.10 HugeTimeGapException
原因:起飛時間和到達時間超過一天。
拋出異常方法:判斷每個計劃項的起飛時間晚1d是否比到達時間晚。
/**
* check gap between leaving and arrival
* @throws HugeTimeGapException
*/
public void checkTimeGap() throws HugeTimeGapException {
List<PlanningEntry<Resource>> entries = this.getAllPlanningEntries();
int n = entries.size();
for (int i = 0; i < n - 1; i++) {
FlightSchedule<Resource> e = (FlightSchedule<Resource>) entries.get(i);
LocalDateTime t1 = e.getTimeLeaving(), t2 = e.getTimeArrival();
if (t1.plusDays(1).isBefore(t2))
throw new HugeTimeGapException(t1.toString() + " is to early than " + t2.toString());
}
}
3.1.1.11 EntryInconsistentInfoException
原因:相同航班號的航班信息(起降地點/時間)不一致。
拋出異常方法:檢查每一對計劃項,得到其時間和地點對象。
/**
* check entry information consistent
* @throws EntryInconsistentInfoException
*/
public void checkEntryConsistentInfo() throws EntryInconsistentInfoException {
List<PlanningEntry<Resource>> entries = this.getAllPlanningEntries();
int n = entries.size();
for (int i = 0; i < n - 1; i++) {
for (int j = i + 1; j < n; j++) {
if (i != j) {
FlightSchedule<Resource> e1 = (FlightSchedule<Resource>) entries.get(i),
e2 = (FlightSchedule<Resource>) entries.get(j);
if (e1.getPlanningEntryNumber().equals(e2.getPlanningEntryNumber())) {
LocalTime t11 = e1.getTimeLeaving().toLocalTime(), t12 = e1.getTimeArrival().toLocalTime(),
t21 = e2.getTimeLeaving().toLocalTime(), t22 = e2.getTimeArrival().toLocalTime();
if (!(t11.equals(t21) && t12.equals(t22)) || !e1.getLocation().equals(e2.getLocation()))
throw new EntryInconsistentInfoException(e1.getPlanningEntryNumber() + " and " e2.getPlanningEntryNumber() + " is inconsistent.");
}
}
}
}
}
3.1.1.12 PlaneInconsistentInfoException
原因:不同的航班中出現相同的飛機。
拋出異常方法:遍歷每一對飛機,若飛機號相同,但內容不相同,則出現不一致信息。
/**
* check plane information consistent
* @throws PlaneInconsistentInfoException
*/
public void checkPlaneConsistentInfo() throws PlaneInconsistentInfoException {
Set<Resource> planes = this.getAllResource();
for (Resource r1 : planes) {
for (Resource r2 : planes) {
if (r1 != r2) {
Plane p1 = (Plane) r1, p2 = (Plane) r2;
if (p1.getNumber().equals(p2.getNumber()) && !p1.equals(p2))
throw new PlaneInconsistentInfoException(p1.getNumber() + " has inconsistent information.");
}
}
}
}
3.1.1.13 SameEntrySameDayException
原因:相同航班號的航班在同一天。
拋出異常方法:遍歷比較
/**
* check same entry in different days
* @throws SameEntrySameDayException
*/
public void checkSameEntryDiffDay() throws SameEntrySameDayException {
List<PlanningEntry<Resource>> entries = this.getAllPlanningEntries();
int n = entries.size();
for (int i = 0; i < n - 1; i++) {
for (int j = i + 1; j < n; j++) {
if (i != j) {
PlanningEntry<Resource> e1 = entries.get(i), e2 = entries.get(j);
if (e1.getPlanningEntryNumber().equals(e2.getPlanningEntryNumber())) {
if (((CommonPlanningEntry<Resource>) e1).getPlanningDate()
.isEqual(((CommonPlanningEntry<Resource>) e2).getPlanningDate()))
throw new SameEntrySameDayException();
}
}
}
}
}
3.1.2 處理客戶端操作時產生的異常
在App中遇到客戶端操作異常時,拋出異常後使用Logger記錄,並取消該操作。
3.1.2.1 DeleteAllocatedResourceException
原因:在刪除某資源的時候,如果有尚未結束的計劃項正在佔用該資源。
拋出異常方法:遍歷計劃項,對於多個使用該資源的計劃項,均檢查計劃項狀態。捕獲到異常後將“允許刪除標籤”設爲false,最後顯示彈窗聲明刪除失敗。
Resource deletingResource = allResourceList.get(num);
boolean flag = true;
try {
checkResourceAllocated(flightScheduleCollection, deletingResource);
} catch (DeleteAllocatedResourceException e1) {
logger.log(Level.WARNING, e1.getMessage(), e1);
flag = false;
}
flag &= flightScheduleCollection.deleteResource(deletingResource);
JOptionPane.showMessageDialog(resourceFrame, flag ? "Successful" : "Failed", "Deleting Resource", JOptionPane.PLAIN_MESSAGE);
3.1.2.2 DeleteOccupiedLocationException
原因:在刪除某位置的時候,如果有尚未結束的計劃項正在該位置執行。
拋出異常方法:遍歷計劃項,對於多個使用該位置的計劃項,均檢查計劃項狀態。
(與上DeleteAllocatedResourceException
同理)
Check方法Spec如下:
/**
* check location occupied
* @param flightScheduleCollection0
* @param location
* @throws DeleteOccupiedLocationException
*/
public static void checkLocationOccupied(FlightScheduleCollection flightScheduleCollection0, String location)
throws DeleteOccupiedLocationException {
List<PlanningEntry<Resource>> planningEntries = flightScheduleCollection0.getAllPlanningEntries();
for (PlanningEntry<Resource> planningEntry : planningEntries) {
FlightSchedule<Resource> flightSchedule = (FlightSchedule<Resource>) planningEntry;
if (flightSchedule.getLocationOrigin().equals(location)
|| flightSchedule.getLocationTerminal().equals(location))
if (planningEntry.getState().getState().equals(EntryStateEnum.ALLOCATED)
|| planningEntry.getState().getState().equals(EntryStateEnum.BLOCKED)
|| planningEntry.getState().getState().equals(EntryStateEnum.RUNNING))
throw new DeleteOccupiedLocationException(location + " is occupied");
}
}
3.1.2.3 UnableCancelException
原因:在取消某計劃項的時候,如果該計劃項的當前狀態不允許取消。
拋出異常方法:通過cancelPlanningEntry()
–>setNewState()
返回的Boolean來判斷是否可取消。
operationFlag = flightScheduleCollection.cancelPlanningEntry(planningEntryNumber);
if (!operationFlag)
try {
throw new UnableCancelException();
} catch (UnableCancelException e1) {
logger.log(Level.WARNING, e1.getMessage(), e1);
}
3.1.2.4 ResourceSharedException
原因:在爲某計劃項分配某資源的時候,如果分配後會導致與已有的其他計劃項產生“資源獨佔衝突”。
拋出異常方法:與DeleteAllocatedResourceException
類似,與其不同的是在分配資源是遍歷查找。
boolean flag = true;
try {
checkResourceShared(flightScheduleCollection, flightScheduleCollection.getPlaneOfNumber(strResourceNumber));
} catch (ResourceSharedException e1) {
logger.log(Level.WARNING, e1.getMessage(), e1);
flag = false;
}
if (flag) flightScheduleCollection.allocateResource(strPlanningEntryNumber, strResourceNumber);
JOptionPane.showMessageDialog(allocateResourceFrame, flag ? "Successfully" : "Failed", "Allocate Resource", JOptionPane.PLAIN_MESSAGE);
3.1.2.5 LocationSharedException
原因:在爲某計劃項變更位置的時候,如果變更後會導致與已有的其他計劃項產生“位置獨佔衝突”。
拋出異常方法:與ResourceSharedException
同理。該功能在Activity Calendar App
中。
/**
* check location modifiable
* @param flightScheduleCollection0
* @param location
* @throws LocationSharedException
*/
public static void checkLocationModifiable(FlightScheduleCollection flightScheduleCollection0, String location)
throws LocationSharedException {
List<PlanningEntry<Resource>> planningEntries = flightScheduleCollection0.getAllPlanningEntries();
for (PlanningEntry<Resource> planningEntry : planningEntries) {
ActivityCalendar<Resource> activityCalendar = (ActivityCalendar<Resource>) planningEntry;
if (activityCalendar.getLocation() != null && activityCalendar.getLocation().equals(location))
throw new LocationSharedException(location + " is shared.");
}
}
3.2 Assertion and Defensive Programming
3.2.1 checkRep()檢查rep invariants
3.2.1.1 TimeSlot
TimeSlot
的AF、RI如下:
/*
* AF:
* arrival[i] represent the time it arrives locations[i]
* leaving[i] represent the time it leaves locations[i]
*
* when Flight Schedule:
* length == 2, arrival[0] == leaving[0], arrival[1] == leaving[1]
*
* when Activity Schedule:
* length == 1, arrival[0] is ending time, leaving[0] is beginning time
*
* RI:
* the length of arrival and leaving should be equal
* leaving[i] should be later than arrival[i]
* when i<length arrival[i] and leaving[i] should be non-null
*
* Safety:
* do not provide mutator
*/
由此可以設計checkRep()
方法:
/**
* check Rep
*/
private void checkRep() {
assert (arrival.size() == leaving.size());
for (int i = 0; i < arrival.size(); i++) {
assert (arrival.get(i) != null);
assert (leaving.get(i) != null);
}
}
3.2.1.2 Location
Location
的AF、RI如下:
/*
* AF:
* locations represent the locations in the plan
*
* RI:
* locations should be as long as arrival and leaving in class TimeSlot
*
* Safety:
* do not provide mutator
*/
Location的Representation可以保證包括航班和高鐵在內的“任意兩個站不相同”。該checkRep()
如下:
/**
* check Rep
*/
private void checkRep() {
for (String strLocation1 : locations) {
assert (strLocation1.length() > 0);
for (String strLocation2 : locations) {
if (strLocation1 != strLocation2)
assert (!strLocation1.equals(strLocation2));
}
}
}
3.2.1.3 EntryState
EntryState
的AF、RI如下:
/*
* AF:
* the state enum's name represents the state
* RI:
* state must be in enums
* Safety:
* it's a mutable object, but do not let the outside modify state directly
*/
該checkRep()
非常容易,略。
3.2.1.4 Resource
Resource
的3個實現類均是immutable類型ADT,存儲一定信息,因此其checkRep就是保證信息存儲的變量符合格式,檢查方法與拋出異常方法類似,因此對拋出異常的方法進行復用。以Plane爲例:
/**
* check Rep
*/
private void checkRep() {
try {
FlightScheduleCollection.checkPlaneNumber(number);
} catch (PlaneNumberFormatException e) {
assert false;
}
try {
FlightScheduleCollection.checkPlaneType(strType);
} catch (PlaneTypeException e) {
assert false;
}
try {
FlightScheduleCollection.checkPlaneSeat(String.valueOf(intSeats));
} catch (PlaneSeatRangeException e) {
assert false;
}
try {
FlightScheduleCollection.checkPlaneAge(Double.toString(age));
} catch (PlaneAgeFormatException e) {
assert false;
}
}
3.2.1.5 PlanningEntry
在新建計劃項時,資源、位置、時間、狀態均被檢查過,因此只要檢查4者不爲空,且標籤正確即可。
private void checkRep() {
assert (strPlanningEntryType.equals("FlightSchedule"));
assert (location != null);
assert (timeSlot != null);
assert (state != null);
assert (resource != null);
}
3.2.2 Assertion/異常機制來保障pre-/post-condition
Assertion主要針對mutable對象的mutator。
3.2.2.1 EntryState
在修改狀態時,前置條件和後置條件均爲:當前狀態合法。除了類型爲高鐵,否則不能爲blocked。因此判斷兩次狀態的合法性。
/**
* set the new state
* @param strPlanningEntryType in {"FlightSchedule", "TrainSchedule", "ActivityCalendar"}
* @param strNewState
* @return true if the setting is successful, false if not
*/
public Boolean setNewState(String strPlanningEntryType, String strNewState) {
assert (strPlanningEntryType.toLowerCase().contains("train")
|| !this.getStrState().toLowerCase().equals("blocked"));
if (this.setAvailability(strPlanningEntryType, strNewState.toUpperCase())){
this.state = EntryStateEnum.valueOf(strNewState.toUpperCase());
assert (strPlanningEntryType.toLowerCase().contains("train")
|| !this.getStrState().toLowerCase().equals("blocked"));
return true;
}
return false;
}
3.2.2.2 PlanningEntry
計劃項的mutator在於分配資源和更改狀態。
分配資源時,前置條件爲:被分配的資源不能爲空。以ActivityCalendar爲例:
/**
* allocate the resource to the flight schedule
* set the state as ALLOCATED
* @param resource
* @param intResourceNumber
* @return true if the resource is set and state is ALLOCATED
*/
public Boolean allocateResource(R resource, int intResourceNumber) {
assert (resource != null && intResourceNumber > 0);
super.resource = resource;
this.intResourceNumber = intResourceNumber;
return this.state.setNewState(strPlanningEntryType, "Allocated");
}
更改狀態時,後置條件爲:更改後的狀態不能爲空且爲某一合法狀態。以CommonPlanningEntry.start()
爲例:
@Override
public Boolean start() {
boolean flag = this.state.setNewState(strPlanningEntryType, "Running");
assert (this.state != null && this.state.getState() != null);
return flag;
}
其中,PlanningEntry
中的TrainSchedule
有操作“取第i個車廂”,對於該i的前置條件爲:不能查詢第1個站的到達時間且不能查詢最後一個站的出發時間。以查詢出發時間爲例:
/**
* get the LocalDateTime of leaving time of No.indexLocation Location
* @param indexLocation
* @return the LocalDateTime of leaving time of No.indexLocation Location
*/
public LocalDateTime getLeavingTimeOfIndex(int indexLocation) {
assert (indexLocation != TERMINAL);
return super.getTimeSlot().getLeaving().get(indexLocation);
}
3.2.2.3 PlanningEntryCollection
在計劃項集合類中,有許多關聯到計劃項編號的操作,前置條件要求計劃項編號參數不能爲blank。同理,所有有關查詢操作的參數均不能爲空白。
/**
* search for a planning entry whose number matches the given
* @param planningEntryNumber
* @return the planning entry
*/
public PlanningEntry<Resource> getPlanningEntryByStrNumber(String planningEntryNumber) {
assert (!planningEntryNumber.isBlank());
for (PlanningEntry<Resource> planningEntry : planningEntries)
if (planningEntry.getPlanningEntryNumber().equals(planningEntryNumber))
return planningEntry;
return null;
}
3.2.3 你的代碼的防禦式策略概述
代碼的“錯誤傳遞”發生在客戶端到API、API到ADT之間,因此在這兩種傳遞過程的起始和完成階段,都應該進行防禦。
3.2.3.1 Client–>API前置條件防禦
客戶端和API之間,需要基於用戶輸入參數進行功能控制,因此用戶輸入的內容正確性決定了API功能實現的正確性。客戶端的輸入方法或API的方法起始階段需要對用戶輸入進行檢查。
例如FlightScheduleCollection.addPlanningEntry()中需要讀入一段數據,在方法中進行了對各項參數的檢查,錯誤則拋出包括EntryNumberFormatException在內的相應異常;而在查詢指定計劃項信息時,則是在FlightScheduleApp中先對該編號正確性進行檢查(該操作委派給了FlightScheduleCollection)然後才獲取指定信息。
3.2.3.2 Client–>API後置條件防禦
在API操作完成之後,在客戶端或API中需要對結果進行正確性的大致檢查,避免一下明顯錯誤情況;若API操作不當,可能在程序中引入隱式錯誤。
例如在啓動計劃項時,FlightScheduleApp在完成操作後彈窗顯示操作結果;在暫停計劃項之後,會檢查該計劃項類型是否爲可暫停的計劃項對象類型。
3.2.3.3 API–>ADT前置條件防禦
在API的操作會對ADT進行影響,若ADT爲可變的,則要求Setter()參數正確。檢查參數正確可以在API的方法中,也可以在ADT的方法中。
例如API在獲得某計劃項的資源時,會判斷該ADT的資源是否爲空;在API需要獲得高鐵的第i站的到達時間,在ADT的方法中會對i的取值進行斷言(不能爲0)。
3.2.3.4 API–>ADT後置條件防禦
在修改ADT的內容之後,需要確認修改後的ADT符合RI。此時,可以調用ADT私有方法checkRep()進行校驗。在各個ADT中均有checkRep(),出現在構造器(immutable對象),也會出現在mutator(mutable對象)。
3.3 Logging
我報告基本寫完了,但是在這歇會,因爲我料:寫到這的人也不會參考我,會參考我的人也不會寫到這