//TextReverserApplet.java

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

/**
 * Creates an applet containing a TextReverserPanel.
 * Will run as either an applet or an application.
 * <p>
 * If run as an applet, it can either be embedded in a webpage
 * or create a pop-up window.  The applet behavior is
 * determined by the parameter "popup", which should be set
 * to true or false in the enclosing HTML document.
 * The default is to run embedded.
 *
 * @author Zach Tomaszewski
 * @version 05 April 2005
 */
public class TextReverserApplet extends Applet {
    
  /**
   * Runs as an applet, either as an embedded Panel or as a pop-up Frame,
   * depending on this applet's parameters.
   */
  public void init() {
    if ("true".equalsIgnoreCase(this.getParameter("popup"))) {
      //conditional above reversed to avoid NPE
      this.runAsFrame();
    }else {
      this.add(new TextReverserPanel());
    }
  }
  
  /**
   * Runs this applet as an application, opening a Frame.
   */
  public static void main(String[] args){
    TextReverserApplet app = new TextReverserApplet();
    app.runAsFrame();
  }
  

  /**
   * Creates a Frame ("popup" window) and sets it visible.
   */
  protected void runAsFrame() {  
    Frame popup = new Frame();
    popup.add(new TextReverserPanel());
    popup.setTitle(("Text Reverser"));
    popup.setSize(300, 100);     //size of window
    popup.setLocation(200, 200);  //position on screen
    //add an anonymous class that extends WindowAdapter to get the X
    //(close window) button to work.
    popup.addWindowListener(new WindowAdapter() {
                              public void windowClosing(WindowEvent we) {
                                we.getWindow().setVisible(false);
                                try {
                                  System.exit(0); //applets don't exit like this
                                                  //but applications do
                                }catch (SecurityException se) {
                                  //oh well, didn't need to exit for applet anyway
                                }
                              }
                            });   
    popup.setVisible(true);
  }
}//end class



/**
 * A panel that reverses the user's input.
 * Contains a text field and a "Reverse" button.
 * 
 * @author Zach Tomaszewski
 * @version 05 Apr 2005
 */
class TextReverserPanel extends Panel implements ActionListener {

  private Button reverseButton;
  private TextField inputField;
  
  /**
   * Creates a new Panel and adds the component button
   * and text field to the interface.
   */
  public TextReverserPanel() {
    reverseButton = new Button("Reverse");
    inputField = new TextField(20);
    this.add(inputField);
    this.add(reverseButton);
    reverseButton.addActionListener(this);
    inputField.addActionListener(this);
  }
  
  /**
   * Reverses any text in this applet's text field.
   */
  public void actionPerformed(ActionEvent ae){
    StringBuffer text = new StringBuffer(this.inputField.getText());
    text.reverse();
    this.inputField.setText(text.toString());   
  }
  
}//end class