Swing Hacks

454

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Chapter 12, Miscellany

#91 Check Your Mail with Swing

HACK

moveMouse(delete, delete, 1000);

moveMouse(delete, showme, 500);

} catch (Exception ex) {

System.out.println(""+ex);

}

}

The event handler moves the cursor from the

showme

button, which is where

the cursor will already be anyway, to the

info toolbar button over a period

of two seconds. After that, the cursor will hop from button to button taking

one second to move with a one second pause over each button. Finally, the

cursor rushes back to the

showme button in a half-second. It is important to

return the cursor to its starting position so that the user won’t have to hunt

for it after the animation is complete. It’s best to always return things to the

state you found them.

H A C K

#91

Check Your Mail with Swing Hack #91

Add email checking to your application with just a few method calls.

As email becomes a bigger part of our daily lives, I have seen it creep into

more and more places. My email program alerts me when there is new mail.

I can check my email via the phone. I log in to my web mail from an Inter-

net cafe. Email is everywhere, so why shouldn’t it be in your Swing applica-

tion? This hack shows how to embed in your application an email checker

that shows the current number of unread messages and can launch the

user’s email application.

Dealing with email servers can be a complicated and tricky business. To

help address these issues, Sun created the JavaMail API, which is a set of

classes defining a vendor-neutral interface for accessing email servers.

Sun’s sample implementation provides IMAP support, which

is what I will demonstrate here. If you have another kind of

email server, such as Exchange, you could install your own

service provider and use it the same way.

The code in this hack needs to do two things. First, it must open a connec-

tion to the email server periodically and check for new mail. Second, it must

launch the user’s email program on a double-click. I have encapsulated the

email checking and launching code into separate classes, making it very easy

to add to an existing program.

Check Your Mail with Swing #91

Chapter 12, Miscellany

|

455

HACK

The EmailChecker class, shown in Example 12-5, is a simple Runnable imple-

mentation that receives a

JLabel to its constructor. The run loop will sleep

for a certain amount of time (one minute in this case) then call

checkEmail( )

.

Every time there is new mail, it will set the text of the label to something like

“You have

N

new messages.”

Next comes the

checkEmail( ) implementation:

public synchronized void checkEmail( ) throws Exception {

String username = "[e-mail]";

String password = "satans";

String hostname = "code.joshy.org";

int port = 143;

Properties props = System.getProperties( );

Session sess = Session.getDefaultInstance(props);

sess.setDebug(true);

To actually check the email, you need to first collect the relevant parame-

ters: the username, password, hostname of the email server, and the port

(usually 143 for IMAP servers). In addition to this information, you also

need a copy of the system properties to allocate an email

Session.

Example 12-5. Checking for new messages

import java.util.Properties;

import javax.swing.JLabel;

import javax.swing.SwingUtilities;

import javax.mail.*;

public class EmailChecker implements Runnable {

private JLabel label;

public EmailChecker(JLabel label) {

this.label = label;

}

public void run( ) {

while(true) {

try {

checkEmail( );

Thread.currentThread( ).sleep(1000*60); // sleep 1 min

} catch (Exception ex) {

System.out.println("exception: " + ex);

ex.printStackTrace( );

}

}

}