Swing Hacks

Provide Audio Controls During Playback #78

Chapter 10, Audio

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401

HACK

Of course, Sun could just go and actually implement getLevel( )…wouldn’t

that be nice?

H A C K

#78

Provide Audio Controls During Playback Hack #78

Let your users take control of JavaSound playback.

To complete this set of JavaSound-related hacks, why not give the user the

opportunity to control the sound as it plays? JavaSound provides a very

dynamic means of getting at controls like gain and pan (more commonly

thought of as volume and balance) through a discovery mechanism that you

can use to support any kind of control that might exist, even a control you

know nothing about.

On the other hand, JavaSound presents a control not as a GUI widget, but

just as an object that can affect the behavior of a

Line. This hack will help

you provide the GUI side.

The

Control class simply defines a getType( ) and toString( ) method.

What’s more interesting is its subclasses, each of which defines a different

kind of control:

BooleanControl

Controls a value that can be either true or false

EnumControl

Controls a value that can be one of n known values

FloatControl

Controls a value that is expressed as a floating-point number

CompoundControl

Controls multiple properties, and itself contains multiple controls

You can get the

Controls supported by your Line simply by calling Line.

getControls( )

, which returns an array of Controls. You can also ask for a

specific ...