datebean.java

Java实例入门

package beantest;

import java.awt.*;
import java.util.*;
import javax.swing.JLabel;

/**
 * Title:        制作一个JavaBean
 * Description:  这个工程中我们制作了一个用于日期显示的JavaBean
 * Copyright:    Copyright (c) 2001
 * Company:
 * @author
 * @version 1.0
 */

public class DateBean extends JLabel {
  BorderLayout borderLayout1 = new BorderLayout();
  private Color fontColor;
  private int style;
  private boolean useMonthString;

  private Calendar c = Calendar.getInstance();
  private int m, d, y, e;
  private String month, day, year, era, month_str;

  public static final int MONTH_DAY_YEAR     = 1;
  public static final int MONTH_DAY_YEAR_ERA = 2;
  public static final int YEAR_MONTH_DAY     = 3;
  public static final int MONTH_YEAR         = 4;
  public static final int DAY_MONTH_YEAR     = 5;
  public static final String[] allMonths = {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
                                     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
  private transient Vector styleListeners;
  public DateBean() {
    try {
      jbInit();
    }
    catch(Exception ex) {
      ex.printStackTrace();
    }
  }
  private void jbInit() throws Exception {
    this.setLayout(borderLayout1);
    m = c.get(Calendar.MONTH) + 1;
      d = c.get(Calendar.DATE);
      y = c.get(Calendar.YEAR);
      e = c.get(Calendar.ERA);

      if(m <= 9)
        month = "0" + String.valueOf(m);
      else
        month = String.valueOf(m);

      if(d <=9)
        day = "0" + String.valueOf(d);
      else
        day = String.valueOf(d);

      year = String.valueOf(y);
      month_str = allMonths[m - 1];

      // AD or BC -- it might matter when Java builds time machines!
      if(e == 1)
        era = "AD";
      else
        era = "BC";

      setStyle(MONTH_DAY_YEAR_ERA);
      useMonthString = false;
  }

  public void setFontColor(Color newFontColor) {
    super.setForeground(newFontColor);
  }
  public Color getFontColor() {
    return super.getForeground() ;
  }
  public void setStyle(int newStyle) {
   if(newStyle!=this.style ){
         StyleEvent e=new StyleEvent(this);
         e.setNewStyle(newStyle);
         e.setOldStyle(this.style);
        this.fireStyleChanged(e);
        this.style = newStyle;
        switch(style){
          case MONTH_DAY_YEAR:
           if(useMonthString)
              this.setText(month_str + " " + day + ", " + year);
           else
              this.setText(month + " / " + day + " / " + year);
           break;

         case MONTH_DAY_YEAR_ERA:
          if(useMonthString)
            this.setText(month_str + " " + day + ", " + year + " " + era);
          else
            this.setText(month + " / " + day + " / " + year + " " + era);
          break;

        case YEAR_MONTH_DAY:
          if(useMonthString)
            this.setText(year + " " + month_str + " " + day);
          else
            this.setText(year + " / " + month + " / " + day);
          break;

        case MONTH_YEAR:
          if(useMonthString)
            this.setText(month_str + " " + year);
          else
            this.setText(month + " " + year);
          break;

        case DAY_MONTH_YEAR:
          if(useMonthString)
            this.setText(day + " " + month_str + " " + year);
          else
            this.setText(day + " / " + month + " / " + year);
          break;

       default:
         this.setText("invalid");
       }
     }
  }
  public int getStyle() {
    return style;
  }
  public void setUseMonthString(boolean useMonthString) {
    this.useMonthString = useMonthString;
    this.setStyle(this.getStyle());
  }
  public boolean isUseMonthString() {
    return useMonthString;
  }
  public void setFont(Font newfont) {
    super.setFont(newfont);
  }
  public Font getFont() {
    return super.getFont();
  }
  public void setBackground(Color newbackground) {
    super.setBackground(newbackground);
  }
  public Color getBackground() {
    return super.getBackground();
  }
  public synchronized void removeStyleListener(StyleListener l) {
    if (styleListeners != null && styleListeners.contains(l)) {
      Vector v = (Vector) styleListeners.clone();
      v.removeElement(l);
      styleListeners = v;
    }
  }
  public synchronized void addStyleListener(StyleListener l) {
    Vector v = styleListeners == null ? new Vector(2) : (Vector) styleListeners.clone();
    if (!v.contains(l)) {
      v.addElement(l);
      styleListeners = v;
    }
  }
  protected void fireStyleChanged(StyleEvent e) {
    if (styleListeners != null) {
      Vector listeners = styleListeners;
      int count = listeners.size();
      for (int i = 0; i < count; i++) {
        ((StyleListener) listeners.elementAt(i)).styleChanged(e);
      }
    }
  }
}