引发并捕获异常

问题描述 投票：0回答：1

我有一个Java作业，但在以下几点上有些卡住：

  1. 创建WindowMalfunction和PowerOut事件以模拟GreenhouseControls中可能发生的问题。该事件应在GreenhouseControls中适当设置以下布尔变量：windowok = false;poweron =假；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。
  2. 如果从WindowMalfunction或PowerOut引发异常，则控制器将捕获该异常，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。
  3. 在GreenhouseControls中添加一个称为错误代码的实例变量。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，它会在退出之前进行序列化并将整个GreenhouseControls对象保存在当前目录的dump.out文件中。]

    4. 这是我到目前为止所做的（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() {

        }
    }

需要一些上下文，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();
} ///:~

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...

java
1个回答
0
投票

添加了代码注释以了解它。

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