buttonmaker.java

这个文件里面包含了java设计模式的一些例子讲解

package com.javapatterns.factorymethod.instantiate;

import java.awt.*;
import java.awt.event.*;
import java.io.*;


/**
 *
 * The purpose of this class is to create a button, set its label,
 * font and color and then serialize it to a file.  To execute
 * this program, use the command:
 *
 *   java ButtonMaker [label] [font size] [Color]
 *
 * The parameters specify the attributes of the button and will
 * also be used to construct the name of the file as follows:
 *
 *    [label][font size][Color].ser
 *
 * The "label" may be any suitable label and will be used as is.
 * The font size will also be used as is; however, a font size of
 * zero will mean the default size.  The color should be a letter
 * code: r)ed, g)reen, b)lue, y)ellow.  Anything else will result
 * in the default color.
 *
 */
public class ButtonMaker extends Frame {

   /**
    *
    * This constructs a frame window which will show the
    * button and the button itself utilizing the attributes
    * specified.  It also serializes the button to a file
    * for reuse in other programs.  The name of the file
    * is constructed from the button attributes as previously
    * described.
    *
    * @param      label       Button label
    * @param      size        Point size for the font or 0
    *                         for the default.
    * @param      color       Color code (R, G, B, Y or anything
    *                         else for the default.
    *
    */
   ButtonMaker(String label, int size, String color) {

      /*
       * Invoke the super class constructor, add an event listener
       * for the "close" event and change the layout to "Flow".
       */
      super("Button Maker");
      addWindowListener(new Wadapt());
      setLayout(new FlowLayout());

      /*
       * Make the button and serialize it.
       */
      Button b = makeButton(label, size, color);
      serializeButton(b, label+size+color.charAt(0)+".ser");
      add(b);
   }
   

   /**
    *
    * This method constructs a button and changes its attributes
    * based on the parameters specified.  
    *
    * @param      label    Label to assign to button
    * @param      size     Size of font or 0 for default
    * @param      color    Color (red, green, blue or yellow
    *                      or anything else for the default.
    *
    * @return              Button component
    *
    */
   private Button makeButton(String label, int size, String color) {


      /*
       * Set the label.
       */
      Button button = new Button(label);

      /*
       * Set the font size unless the default size of 0 is specified.
       */
      if (size > 0) {
         Font font = new Font("Helvetica", Font.BOLD, size);
         button.setFont(font);
      }

      /*
       * Set the background color of the button to red, green, blue,
       * yellow.
       */
      switch (color.charAt(0)) {

         case 'R':
         case 'r':
            button.setBackground(Color.red);
            break;

         case 'B':
         case 'b':
            button.setBackground(Color.blue);
            break;

         case 'G':
         case 'g':
            button.setBackground(Color.green);
            break;

         case 'Y':
         case 'y':
            button.setBackground(Color.yellow);
            break;

         default:
            break;

      }

      return button;

   }

   /**
    *
    * This method writes a serialized version of the button to 
    * the file name specified.
    *
    * @param      button      Button to serialize
    * @param      filename    Name of the file to use
    *
    */
   private void serializeButton(Button button, String filename) {

      try {

         FileOutputStream outStream = new FileOutputStream(filename);
         ObjectOutputStream out = new ObjectOutputStream(outStream);
         out.writeObject(button);
         out.flush();
         out.close();
      }
      catch (Exception e) {

         System.out.println(e);

      }

   }


   /**
    *
    * This method creates the frame which will construct and show
    * the button. The frame is displayed with a size of (0, 0, 300, 200).
    *
    * @params     args        arg[0] = label text; arg[1] = font size;
    *                         arg[2] = background color
    *
    */
   public static void main(String args[]) {

      /*
       * Check for the correct number of arguments.  If not found, then
       * display an error; otherwise, create and show the frame.
       */
      if (args.length < 3)
         System.out.println("java ButtonMaker [label] [font size] [color]");
      else {
         Frame frame = new ButtonMaker(args[0], Integer.parseInt(args[1]), args[2]);
         frame.setBounds(0,0,300,200);
         frame.setVisible(true);
      }

   }

   /**
    *
    * This "inner" class listens for the event which indicates that
    * the window is closing.  
    *
    */
   class Wadapt extends WindowAdapter {
    
      /**
       *
       * This method handles the event which indicates that a window
       * is closing. If encountered, then it hides the frame, fees
       * the resources and exits.
       *
       * @param   evt         Event object
       */
      public void windowClosing(WindowEvent evt) {

         Frame frame = (Frame)evt.getSource();
         frame.setVisible(false);
         frame.dispose();
         System.exit(0);

      }
   }

}