Source: org/terraswarm/accessor/accessors/web/test/TestSpontaneous.js

// Test accessor that spontaneously produces outputs once per time interval.
//
// Copyright (c) 2015-2016 The Regents of the University of California.
// All rights reserved.
//
// Permission is hereby granted, without written agreement and without
// license or royalty fees, to use, copy, modify, and distribute this
// software and its documentation for any purpose, provided that the above
// copyright notice and the following two paragraphs appear in all copies
// of this software.
//
// IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
// FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
// ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
// THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
//
// THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
// PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
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//

/** Test accessor that spontaneously produces outputs once per time interval.
 *  This implementation produces a counting sequence.
 *
 *  @accessor test/TestSpontaneous
 *  @parameter interval The interval between outputs in milliseconds.
 *  @output output Output for the counting sequence, of type number.
 *  @author Edward A. Lee
 *  @version $$Id$$
 */

// Stop extra messages from jslint.  Note that there should be no
// space between the / and the * and global.
/*globals clearInterval, exports, require, setInterval */
/*jshint globalstrict: true*/
"use strict";

exports.setup = function () {
    this.parameter('interval', {
        'type': 'number',
        'value': 1000
    });
    this.output('output', {
        'type': 'number'
    });
};

// These variables will not be visible to subclasses.
var handle = null;
var count = 0;

exports.initialize = function () {
    count = 0;
    // Need to record 'this' for use in the callback.
    var thiz = this;
    handle = setInterval(function () {
        thiz.send('output', count);
        count += 1;
    }, this.getParameter('interval'));
};

exports.wrapup = function () {
    if (handle) {
        clearInterval(handle);
        handle = null;
    }
};