greenhousecontrols.java

Java编程思想 第八课 全源码

//: c08:GreenhouseControls.java
// From 'Thinking in Java, 2nd ed.' by Bruce Eckel
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
// This produces a specific application of the
// control system, all in a single class. Inner
// classes allow you to encapsulate different
// functionality for each type of event.
import controller.*;

public class GreenhouseControls 
    extends Controller {
  private boolean light = false;
  private boolean water = false;
  private String thermostat = "Day";
  private class LightOn extends Event {
    public LightOn(long eventTime) {
      super(eventTime);
    }
    public void action() {
      // Put hardware control code here to 
      // physically turn on the light.
      light = true;
    }
    public String description() {
      return "Light is on";
    }
  }
  private class LightOff extends Event {
    public LightOff(long eventTime) {
      super(eventTime);
    }
    public void action() {
      // Put hardware control code here to 
      // physically turn off the light.
      light = false;
    }
    public String description() {
      return "Light is off";
    }
  }
  private class WaterOn extends Event {
    public WaterOn(long eventTime) {
      super(eventTime);
    }
    public void action() {
      // Put hardware control code here
      water = true;
    }
    public String description() {
      return "Greenhouse water is on";
    }
  }
  private class WaterOff extends Event {
    public WaterOff(long eventTime) {
      super(eventTime);
    }
    public void action() {
      // Put hardware control code here
      water = false;
    }
    public String description() {
      return "Greenhouse water is off";
    }
  }
  private class ThermostatNight extends Event {
    public ThermostatNight(long eventTime) {
      super(eventTime);
    }
    public void action() {
      // Put hardware control code here
      thermostat = "Night";
    }
    public String description() {
      return "Thermostat on night setting";
    }
  }
  private class ThermostatDay extends Event {
    public ThermostatDay(long eventTime) {
      super(eventTime);
    }
    public void action() {
      // Put hardware control code here
      thermostat = "Day";
    }
    public String description() {
      return "Thermostat on day setting";
    }
  }
  // An example of an action() that inserts a 
  // new one of itself into the event list:
  private int rings;
  private class Bell extends Event {
    public Bell(long eventTime) {
      super(eventTime);
    }
    public void action() {
      // Ring every 2 seconds, 'rings' times:
      System.out.println("Bing!");
      if(--rings > 0)
        addEvent(new Bell(
          System.currentTimeMillis() + 2000));
    }
    public String description() {
      return "Ring bell";
    }
  }
  private class Restart extends Event {
    public Restart(long eventTime) {
      super(eventTime);
    }
    public void action() {
      long tm = System.currentTimeMillis();
      // Instead of hard-wiring, you could parse
      // configuration information from a text
      // file here:
      rings = 5;
      addEvent(new ThermostatNight(tm));
      addEvent(new LightOn(tm + 1000));
      addEvent(new LightOff(tm + 2000));
      addEvent(new WaterOn(tm + 3000));
      addEvent(new WaterOff(tm + 8000));
      addEvent(new Bell(tm + 9000));
      addEvent(new ThermostatDay(tm + 10000));
      // Can even add a Restart object!
      addEvent(new Restart(tm + 20000));
    }
    public String description() {
      return "Restarting system";
    }
  }
  public static void main(String[] args) {
    GreenhouseControls gc = 
      new GreenhouseControls();
    long tm = System.currentTimeMillis();
    gc.addEvent(gc.new Restart(tm));
    gc.run();
  } 
} ///:~