Grinding Java - Searching the WWW in Java:grinding5.java

import java.awt.*;

/**
 * a class to show a percentage bar with the correct percentage painted in
 * one color and the number of percent on top.
**/
public class ProgressBar extends Panel
{
   /**
    * this constructor accepts the following parameters:
    *  backColor - the color of the border of the window
    *  frontColor - the color of the bar.
    *     textColor - the color in which the percentage figure will be painted.
   **/
   public ProgressBar(Color backColor, Color frontColor, Color textColor)
   {
      backColor  = this.backColor;
      frontColor = this.frontColor;
      textColor  = this.textColor;
      percent = 0;
   }

   /**
    * this constructor accepts the following parameters:
    *  backColor - the color of the border of the window
    *  frontColor - the color of the bar.
    *     textColor - the color in which the percentage figure will be painted.
    *     textFont - the font to use in writing the percentage.
   **/
   public ProgressBar(Color backColor, Color frontColor, Color textColor,
                      Font textFont)
   {
      backColor  = this.backColor;
      frontColor = this.frontColor;
      textColor  = this.textColor;
      setFont(textFont);
      percent = 0;
   }

   /**
    * this method draws the progress bar with the correct percentage filled in.
   **/
   public void paint (Graphics g)
   {
      int width = getSize().width;
      int height = getSize().height;
      g.setColor(backColor);
      g.drawRect(0,0,width-1,height-1);
      g.setColor(frontColor);
      g.fillRect(1,1,(int)((width-2) * ((double)percent) / 100),height-2);

      String percentage = Integer.toString(percent) + "%";
      Font textFont =  g.getFont();
      FontMetrics fntMetric = g.getFontMetrics(textFont);
      int x = (width / 2) - (fntMetric.stringWidth(percentage) / 2);
      int y = (height / 2) - (fntMetric.getHeight() / 2);

      g.setColor(textColor);
      g.drawString(percentage,x,y);
   }

   /**
    * set the size of the progress bar to a new size.
   **/
   void setPercentage(int percent)
   {
      this.percent = percent;
      repaint();
   }

   private int percent;
   private Color backColor;
   private Color frontColor;
   private Color textColor;
}