我有一个Java作业，但在以下几点上有些卡住：
创建WindowMalfunction和PowerOut事件以模拟可能在GreenhouseControls中发生的问题。该事件应在GreenhouseControls中适当设置以下布尔变量：
windowok = false;
poweron = false;
设置变量后，WindowMalfunction或PowerOut应该引发异常，以指定错误条件。为此创建一个ControllerException类，该类扩展了Exception。
如果WindowMalfunction或PowerOut引发了异常，则Controller会捕获该异常，然后使用适当的消息启动紧急关机。向Controller添加一个名为shutdown的方法，并在GreenhouseControls中重写此方法以完成关闭。
在GreenhouseControls中添加一个名为errorcode的实例变量。它使用int变量错误代码（对于WindowMalfunction为1，对于PowerOut为2）中的错误代码指示问题的性质，并在当前目录中名为error.log的文本文件中记录时间和关闭原因，并进行打印到控制台。然后，在退出之前，它将序列化整个GreenhouseControls对象并将其保存在当前目录中的dump.out文件中。
到目前为止，这是我所做的（不多），我不确定如何抛出和捕获异常。
private boolean windowork;
public class WinidowMalfunction extends Event {
public WinidowMalfunction(long delayTime) {
super(delayTime);
}
public void action() {
windowork = false;
}
}
private boolean poweron;
public class PowerOut extends Event {
public PowerOut(long delayTime) {
super(delayTime);
}
public void action() {
poweron = false;
}
}
public class ControllerException extends Exception {
public ControllerEception(String except) {
super(except);
}
public String getMessage() {
return super.getMessage();
}
public void shutdown() {
}
}
如果需要的话，这里是完整的项目代码：
GreenhouseControls.java
import java.io.*;
import java.util.Calendar;
import java.util.Scanner;
import tme3.*;
public class GreenhouseControls extends Controller {
private boolean light = false;
private boolean water = false;
private String thermostat = "Day";
private String eventsFile = "example1.txt";
public class LightOn extends Event {
public LightOn(long delayTime) { super(delayTime); }
public void action() {
// Put hardware control code here to
// physically turn on the light.
light = true;
}
public String toString() { return "Light is on"; }
}
public class LightOff extends Event {
public LightOff(long delayTime) { super(delayTime); }
public void action() {
// Put hardware control code here to
// physically turn off the light.
light = false;
}
public String toString() { return "Light is off"; }
}
public class WaterOn extends Event {
public WaterOn(long delayTime) { super(delayTime); }
public void action() {
// Put hardware control code here.
water = true;
}
public String toString() {
return "Greenhouse water is on";
}
}
public class WaterOff extends Event {
public WaterOff(long delayTime) { super(delayTime); }
public void action() {
// Put hardware control code here.
water = false;
}
public String toString() {
return "Greenhouse water is off";
}
}
public class ThermostatNight extends Event {
public ThermostatNight(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here.
thermostat = "Night";
}
public String toString() {
return "Thermostat on night setting";
}
}
public class ThermostatDay extends Event {
public ThermostatDay(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here.
thermostat = "Day";
}
public String toString() {
return "Thermostat on day setting";
}
}
// An example of an action() that inserts a
// new one of itself into the event list:
public class Bell extends Event {
public Bell(long delayTime) {
super(delayTime);
}
public void action() {
addEvent(new Bell(delayTime));
}
public String toString() { return "Bing!"; }
}
private boolean fans;
public class FansOn extends Event {
public FansOn(long delayTime) {
super(delayTime);
}
public void action() {
fans = true;
}
public String toString() {
return "Fans are on";
}
}
public class FansOff extends Event {
public FansOff(long delayTime) {
super (delayTime);
}
public void action() {
fans = false;
}
public String toString() {
return "Fans are off";
}
}
private boolean windowork;
public class WinidowMalfunction extends Event {
public WinidowMalfunction(long delayTime) {
super(delayTime);
}
public void action() {
windowork = false;
}
}
private boolean poweron;
public class PowerOut extends Event {
public PowerOut(long delayTime) {
super(delayTime);
}
public void action() {
poweron = false;
}
}
public class ControllerException extends Exception {
public ControllerEception(String except) {
super(except);
}
public String getMessage() {
return super.getMessage();
}
public void shutdown() {
}
}
public class Restart extends Event {
public Restart(long delayTime, String filename) {
super(delayTime);
eventsFile = filename;
}
public void action() {
Scanner scanner = new Scanner(eventsFile);
while(scanner.hasNextLine()) {
String line = scanner.nextLine();
}
addEvent(new ThermostatNight(0));
addEvent(new LightOn(2000));
addEvent(new WaterOff(8000));
addEvent(new ThermostatDay(10000));
addEvent(new Bell(2000));
addEvent(new WaterOn(6000));
addEvent(new LightOff(4000));
addEvent(new Terminate(12000));
addEvent(new FansOn(5000));
addEvent(new FansOff(1000));
}
public String toString() {
return "Restarting system";
}
}
public class Terminate extends Event {
public Terminate(long delayTime) { super(delayTime); }
public void action() { System.exit(0); }
public String toString() { return "Terminating"; }
}
public static void printUsage() {
System.out.println("Correct format: ");
System.out.println(" java GreenhouseControls -f <filename>, or");
System.out.println(" java GreenhouseControls -d dump.out");
}
//---------------------------------------------------------
public static void main(String[] args) {
try {
String option = args[0];
String filename = args[1];
if ( !(option.equals("-f")) && !(option.equals("-d")) ) {
System.out.println("Invalid option");
printUsage();
}
GreenhouseControls gc = new GreenhouseControls();
if (option.equals("-f")) {
gc.addEvent(gc.new Restart(0,filename));
}
gc.run();
}
catch (ArrayIndexOutOfBoundsException e) {
System.out.println("Invalid number of parameters");
printUsage();
}
}
} ///:~
Controller.java
package tme3;
import java.util.*;
public class Controller {
// A class from java.util to hold Event objects:
private List<Event> eventList = new ArrayList<Event>();
public void addEvent(Event c) { eventList.add(c); }
public void run() {
while(eventList.size() > 0)
// Make a copy so you're not modifying the list
// while you're selecting the elements in it:
for(Event e : new ArrayList<Event>(eventList))
if(e.ready()) {
System.out.println(e);
e.action();
eventList.remove(e);
}
}
} ///:~
Event.java
package tme3;
import java.io.*;
public abstract class Event {
private long eventTime;
protected final long delayTime;
public Event(long delayTime) {
this.delayTime = delayTime;
start();
}
public void start() { // Allows restarting
eventTime = System.currentTimeMillis() + delayTime;
}
public boolean ready() {
return System.currentTimeMillis() >= eventTime;
}
public abstract void action();
} ///:~
最佳答案
添加了代码注释以了解它。
GreenhouseControls.java
package tme3;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;
public class GreenhouseControls extends Controller {
private boolean light = false;
private boolean water = false;
private String thermostat = "Day";
private String eventsFile = "example1.txt";
// 3. Add an instance variable in GreenhouseControls called error code.
private int errorCode;
public class LightOn extends Event {
public LightOn(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here to
// physically turn on the light.
light = true;
}
public String toString() {
return "Light is on";
}
}
public class LightOff extends Event {
public LightOff(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here to
// physically turn off the light.
light = false;
}
public String toString() {
return "Light is off";
}
}
public class WaterOn extends Event {
public WaterOn(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here.
water = true;
}
public String toString() {
return "Greenhouse water is on";
}
}
public class WaterOff extends Event {
public WaterOff(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here.
water = false;
}
public String toString() {
return "Greenhouse water is off";
}
}
public class ThermostatNight extends Event {
public ThermostatNight(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here.
thermostat = "Night";
}
public String toString() {
return "Thermostat on night setting";
}
}
public class ThermostatDay extends Event {
public ThermostatDay(long delayTime) {
super(delayTime);
}
public void action() {
// Put hardware control code here.
thermostat = "Day";
}
public String toString() {
return "Thermostat on day setting";
}
}
// An example of an action() that inserts a
// new one of itself into the event list:
public class Bell extends Event {
public Bell(long delayTime) {
super(delayTime);
}
public void action() {
addEvent(new Bell(delayTime));
}
public String toString() {
return "Bing!";
}
}
private boolean fans;
public class FansOn extends Event {
public FansOn(long delayTime) {
super(delayTime);
}
public void action() {
fans = true;
}
public String toString() {
return "Fans are on";
}
}
public class FansOff extends Event {
public FansOff(long delayTime) {
super(delayTime);
}
public void action() {
fans = false;
}
public String toString() {
return "Fans are off";
}
}
private boolean windowork;
public class WinidowMalfunction extends Event {
public WinidowMalfunction(long delayTime) {
super(delayTime);
}
// 1. After setting the variables, WindowMalfunction or PowerOut should throw an
// exception specifying the faulty condition
public void action() throws ControllerException {
windowork = false;
// 3. error code in an int variable error code -> 1 for WindowMalfunction
someThingWentWrongHere(1, "Error at WinidowMalfunction");
}
}
private boolean poweron;
public class PowerOut extends Event {
public PowerOut(long delayTime) {
super(delayTime);
}
// 1. After setting the variables, WindowMalfunction or PowerOut should throw an
// exception specifying the faulty condition
public void action() throws ControllerException {
poweron = false;
// 3. error code in an int variable error code -> 2 for powerOut
someThingWentWrongHere(2, "Error at powerOut event");
}
}
void someThingWentWrongHere(int errorCode, String errorMessage) throws ControllerException {
this.errorCode = errorCode;
throw new ControllerException(errorMessage);
}
public class ControllerException extends Exception {
public ControllerException(String except) {
super(except);
}
public String getMessage() {
return super.getMessage();
}
public void shutdown() {
}
}
public class Restart extends Event {
public Restart(long delayTime, String filename) {
super(delayTime);
eventsFile = filename;
}
public void action() {
Scanner scanner = new Scanner(eventsFile);
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
}
addEvent(new ThermostatNight(0));
addEvent(new LightOn(2000));
addEvent(new WaterOff(8000));
addEvent(new ThermostatDay(10000));
addEvent(new Bell(2000));
addEvent(new WaterOn(6000));
addEvent(new LightOff(4000));
addEvent(new Terminate(12000));
addEvent(new FansOn(5000));
addEvent(new FansOff(1000));
}
public String toString() {
return "Restarting system";
}
}
public class Terminate extends Event {
public Terminate(long delayTime) {
super(delayTime);
}
public void action() {
System.exit(0);
}
public String toString() {
return "Terminating";
}
}
public static void printUsage() {
System.out.println("Correct format: ");
System.out.println(" java GreenhouseControls -f <filename>, or");
System.out.println(" java GreenhouseControls -d dump.out");
}
// ---------------------------------------------------------
public static void main(String[] args) {
GreenhouseControls gc = new GreenhouseControls();
try {
/*
* String option = args[0]; String filename = args[1];
*
* if (!(option.equals("-f")) && !(option.equals("-d"))) {
* System.out.println("Invalid option"); printUsage(); }
*
* if (option.equals("-f")) { gc.addEvent(gc.new Restart(0, filename)); }
*/
// UnCommenting above code will never test below code because above code with
// throw first exception and it will never execute below code
// To test PowerOut fail with exception
// gc.addEvent(gc.new PowerOut(100));
// To test WinidowMalfunction fail with exception
gc.addEvent(gc.new WinidowMalfunction(100));
gc.run();
} catch (ArrayIndexOutOfBoundsException e) {
System.out.println("Invalid number of parameters");
printUsage();
}
// 2. the Controller catches the exception
catch (ControllerException e) {
// 2. then initiates an emergency shutdown with an appropriate message
gc.shutdown(e.getMessage());
}
}
// override this method in GreenhouseControls to accomplish the shutdown.
@Override
protected void shutdown(String message) {
// super.shutdown();
DateFormat df = new SimpleDateFormat("dd/MM/yy HH:mm:ss");
Date dateobj = new Date();
// logs the time and the reason for the shutdown in a text file ,, Here you will
// create file and log it
System.out.println("Shutdown due to Error: " + message + " | Error Code:" + errorCode + " | DateTime:" + df.format(dateobj));
}
/*
* enum ErrorCode { WindowMalfunction, PowerOut }
*/
}
Controller.java
package tme3;
import java.util.*;
import tme3.GreenhouseControls.ControllerException;
public class Controller {
// A class from java.util to hold Event objects:
private List<Event> eventList = new ArrayList<Event>();
public void addEvent(Event c) {
eventList.add(c);
}
public void run() throws ControllerException{
while (eventList.size() > 0)
// Make a copy so you're not modifying the list
// while you're selecting the elements in it:
for (Event e : new ArrayList<Event>(eventList))
if (e.ready()) {
System.out.println(e);
e.action();
eventList.remove(e);
}
}
//2. Add a method to Controller called shutdown,
protected void shutdown(String message) {
System.out.println("ShutDown from controller");
}
}
Event.java
package tme3;
import tme3.GreenhouseControls.ControllerException;
public abstract class Event {
private long eventTime;
protected final long delayTime;
public Event(long delayTime) {
this.delayTime = delayTime;
start();
}
public void start() { // Allows restarting
eventTime = System.currentTimeMillis() + delayTime;
}
public boolean ready() {
return System.currentTimeMillis() >= eventTime;
}
public abstract void action() throws ControllerException;
}