The TrafficLight Component : Customized Component « Swing JFC « Java

1. Java
2. Swing JFC
3. Customized Component

The TrafficLight Component

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.beans.PropertyEditorSupport;
import java.beans.SimpleBeanInfo;
import java.util.TooManyListenersException;
import java.util.Vector;

import javax.swing.JComponent;

public class TrafficLight extends JComponent {

  public static String STATE_RED = "RED";

  public static String STATE_YELLOW = "YELLOW";

  public static String STATE_GREEN = "GREEN";

  private static int DELAY = 3000;

  private String defaultLightState;

  private String currentLightState;

  private boolean debug;

  private Thread runner;

  private transient ActionListener listener;

  public TrafficLight() {
    defaultLightState = currentLightState = STATE_RED;
    setPreferredSize(new Dimension(100, 200));
  }

  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    // Paint the outline of the traffic light
    g.setColor(Color.white);
    g.fillRect(2, 2, 96, 196);
    // Debug
    if (debug) {
      System.out.println("Current light state is: " + currentLightState);
    }
    // Which light is on?
    if (currentLightState.equals(STATE_RED)) {
      g.setColor(Color.red);
      g.fillOval(30, 30, 40, 40);
    } else if (currentLightState.equals(STATE_YELLOW)) {
      g.setColor(Color.yellow);
      g.fillOval(30, 80, 40, 40);
    } else if (currentLightState.equals(STATE_GREEN)) {
      g.setColor(Color.green);
      g.fillOval(30, 130, 40, 40);
    }
  }

  public String getCurrentLightState() {
    return currentLightState;
  }

  public void setCurrentLightState(String currentLightState) {
    this.currentLightState = currentLightState;
    if (currentLightState != STATE_YELLOW) {
      if (debug) {
        System.out.println("Firing action event");
      }
      ActionEvent ae = new ActionEvent(this,
          ActionEvent.ACTION_PERFORMED, currentLightState);
      fireActionPerformed(ae);
    }
    repaint();
  }

  public void setDefaultLightState(String defaultLightState) {
    this.defaultLightState = defaultLightState;
    currentLightState = defaultLightState;
    repaint();
  }

  public String getDefaultLightState() {
    return defaultLightState;
  }

  public void setDebug(boolean debug) {
    this.debug = debug;
  }

  public boolean isDebug() {
    return debug;
  }

  public void initiate() {
    if (debug) {
      System.out.println("Initiate traffic light cycle!");
    }
    startCycle();
  }

  private void startCycle() {
    if (runner == null) {
      Runnable runnable = new Runnable() {
        public void run() {
          if (debug) {
            System.out.println("Started cycle");
          }
          while (runner != null) {
            try {
              Thread.sleep(DELAY);
            } catch (InterruptedException e) {
            }
            if (currentLightState.equals(STATE_RED)) {
              setCurrentLightState(STATE_GREEN);
            } else if (currentLightState.equals(STATE_GREEN)) {
              setCurrentLightState(STATE_YELLOW);
            } else {
              setCurrentLightState(STATE_RED);
            }
            if (currentLightState.equals(defaultLightState)) {
              runner = null;
            }
          }
        }
      };
      runner = new Thread(runnable);
      runner.start();
    }
  }

  public void lightChange(ActionEvent x) {
    String command = x.getActionCommand();
    if (debug) {
      System.out.println("Received event from traffic light: "
          + defaultLightState + " command: go to " + command);
    }

    if (command.equals(STATE_RED)) {
      if (!currentLightState.equals(STATE_GREEN)) {

        currentLightState = STATE_GREEN;
        repaint();
      }
    } else if (command.equals(STATE_GREEN)) {
      if (!currentLightState.equals(STATE_RED)) {
        currentLightState = STATE_YELLOW;
        repaint();
        try {
          Thread.sleep(DELAY);
        } catch (InterruptedException e) {
        }
        currentLightState = STATE_RED;
        repaint();
      }
    }
  }

  public synchronized void removeActionListener(ActionListener l) {
    if (debug) {
      System.out.println("Deregistering listener");
    }
    if (listener == l) {
      listener = null;
    }
  }

  public synchronized void addActionListener(ActionListener l)
      throws TooManyListenersException {
    if (debug) {
      System.out.println("Registering listener");
    }
    if (listener == null) {
      listener = l;
    } else {
      throw new TooManyListenersException();
    }
  }

  protected void fireActionPerformed(ActionEvent e) {
    if (debug) {
      System.out.println("Firing action event");
    }
    if (listener != null) {
      listener.actionPerformed(e);
    }
  }
}

class LightColorEditor extends PropertyEditorSupport {
  public String[] getTags() {
    String values[] = { TrafficLight.STATE_RED, TrafficLight.STATE_YELLOW,
        TrafficLight.STATE_GREEN };
    return values;
  }
}

class TrafficLightBeanInfo extends SimpleBeanInfo {
  public PropertyDescriptor[] getPropertyDescriptors() {
    try {
      PropertyDescriptor pd1 = new PropertyDescriptor("debug",
          TrafficLight.class);
      PropertyDescriptor pd2 = new PropertyDescriptor(
          "defaultLightState", TrafficLight.class);
      pd2.setPropertyEditorClass(LightColorEditor.class);
      PropertyDescriptor result[] = { pd1, pd2 };
      return result;
    } catch (IntrospectionException e) {
      System.err.println("Unexpected exception: " + e);
      return null;
    }
  }
}

class MyBean {
  private transient Vector actionListeners;

  public synchronized void removeActionListener(ActionListener l) {
    if (actionListeners != null && actionListeners.contains(l)) {
      Vector v = (Vector) actionListeners.clone();
      v.removeElement(l);
      actionListeners = v;
    }
  }

  public synchronized void addActionListener(ActionListener l) {
    Vector v = (actionListeners == null) ? new Vector(2)
        : (Vector) actionListeners.clone();
    if (!v.contains(l)) {
      v.addElement(l);
      actionListeners = v;
    }
  }

  protected void fireActionPerformed(ActionEvent e) {
    if (actionListeners != null) {
      Vector listeners = actionListeners;
      int count = listeners.size();
      for (int i = 0; i < count; i++) {
        ((ActionListener) listeners.elementAt(i)).actionPerformed(e);
      }
    }
  }
}
           
       

Related examples in the same category

1.	FontChooser dialog
2.	Oval Panel
3.	Customized component
4.	Ploygon Button
5.	Demonstrating the Box Component
6.	The MyBean JavaBean Component
7.	Alias Bean