Java Reference
In-Depth Information
You can add a main method to enable this applet to run as a standalone application. The
applet takes the parameters from the HTML file when it runs as an applet and takes the para-
meters from the command line when it runs standalone. The program, as shown in Listing
18.6, is identical to
DisplayMessage
except for the addition of a new
main
method and of
a variable named
isStandalone
to indicate whether it is running as an applet or as an
application.
L
ISTING
18.6
DisplayMessageApp.java
1
import
javax.swing.*;
2
import
java.awt.Font;
3
import
java.awt.BorderLayout;
4
5
public class
DisplayMessageApp
extends
JApplet
{
6
private
String message =
"A default message"
;
// Message to display
7
private int
x =
20
;
// Default x-coordinate
8
private int
y =
20
;
// Default y-coordinate
9
10
/** Determine whether it is an application */
11
12
13 @Override
/** Initialize the applet */
14
public void
init() {
15 {
16
// Get parameter values from the HTML file
17 message = getParameter(
"MESSAGE"
);
18 x = Integer.parseInt(getParameter(
"X"
));
19 y = Integer.parseInt(getParameter(
"Y"
));
20 }
21
22
// Create a message panel
23 MessagePanel messagePanel =
new
MessagePanel(message);
24 messagePanel.setFont(
new
Font(
"SansSerif"
, Font.BOLD,
20
));
25 messagePanel.setXCoordinate(x);
26 messagePanel.setYCoordinate(y);
27
28
// Add the message panel to the applet
29 add(messagePanel);
30 }
31
32
/** Main method to display a message
33
@param args[0] x-coordinate
34
@param args[1] y-coordinate
35
@param args[2] message
36
*/
37
public static void
main(String[] args) {
38
// Create a frame
39 JFrame
private boolean
isStandalone =
false
;
isStandalone
if
(!isStandalone)
applet params
frame
=
new
JFrame(
"DisplayMessageApp"
);
40
41
// Create an instance of the applet
42 DisplayMessageApp
applet
=
new
DisplayMessageApp();
43
44
// It runs as an application
45
46
47
applet.isStandalone =
true
;
standalone
// Get parameters from the command line
48
49
50
applet.getCommandLineParameters(args);
command params
// Add the applet instance to the frame
51
frame.add(applet, BorderLayout.CENTER);
