Swing Hacks

Play a Sound with JavaSound #71

Chapter 10, Audio

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367

HACK

The example sets up a LineListener on the Clip and looks at the type of

received events for four values defined in the

LineEvent.Type class: OPEN,

CLOSE

,

START

, and

STOP

. All of these are logged to standard out, and then an

appropriate action is taken:

START

makes the dialog visible,

STOP

hides the

dialog and closes the clip (this is called when you OK the dialog), and

CLOSE

exits the application (and is called as a side effect of

clip.close( )

in the

handling of

STOP).

There are a lot more classes in the package, and you can write really confus-

ing code with them—and I haven’t even mentioned MIDI. But for the stated

goal of playing a small audio file with a minimum of fuss, that’s how you do

it with JavaSound.

Listen Up

When you run the demo program, it brings up a regular JFileChooser. You

need to pick a sound file from one of JavaSound’s supported file formats…

of which there are only three: WAV, AIFF, and AU (not MP3, WMA, or

Ogg). You knew there had to be a catch, right? Moreover, by default, Java-

Sound only plays uncompressed sound files, so if the data in the file is in

ALAW, ULAW, MACE, etc., it won’t play.

If JavaSound can read it, it will start playing the chosen file immediately.

The demo also shows a dialog like Figure 10-3, showing the name of the

chosen audio file.

Clicking the OK button clears the dialog and unblocks the AWT so that

when the clip finishes playing, the

STOP event can remove the dialog from the

screen and close the clip, which exits the demo.

Working with the

AudioSystem and having to pass around description

objects is a little strange, especially with JavaSound’s habit of using public

inner classes as descriptor objects, but thanks to the

Clip class, it does offer

a pretty reasonable way to play small audio clips from your program.

Figure 10-3. Dialog showing current sound file