Accessors support timed and periodic events with the setTimeout() and setInterval() functions. Each takes a callback function and milliseconds as arguments. Any further arguments will be passed to the callback function.

Here, we'll make a clip player that plays the first seconds of a sound clip.

setup() creates an instance of the ClipPlayer accessor. addInputHandler() starts the player upon a start event and stops it 15000 milliseconds later by sending a value to ClipPlayer's stop input. setInterval() is used to execute a function at a certain time in the future.

Click 'react to inputs'. The clip should play for approximately 15 seconds. The clip may take a few seconds to load and start.

Next, add a parameter to control the clip duration.

• In setup(), create a parameter named duration by adding the line this.parameter('duration').
• Edit the setInterval() code to play the clip for duration milliseconds.
• You can get the parameter's value using self.getParameter('duration').
• Click 'instantiate'. The duration parameter should appear.
• Enter a number, in milliseconds, for the duration.
• Click 'react to inputs'. You should hear approximately duration milliseconds of the clip.
• Tip: Try a duration between 10000 and 30000 (10 to 30 seconds).

/** An accessor that plays a sound clip for the specified duration.

* @accessor tutorial/TimedClipPlayer.

* @input start Start playback.

*/

​

exports.setup = function() {

    this.input('start', {'value' : true});

    this.player = this.instantiate('ClipPlayer', 'audio/ClipPlayer');

    this.connect('start', this.player, 'start');

};

​

exports.initialize = function() {

    var self = this;

    // Upon start, stop the player after 15000 milliseconds.

    this.addInputHandler('start', function() {

        setInterval(function() {

            self.player.send('stop', true);

        }, 15000);

    });

};