91 lines
2.4 KiB
JavaScript
91 lines
2.4 KiB
JavaScript
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dojo.provide("dojox.timing.Streamer");
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dojo.require("dojox.timing._base");
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dojox.timing.Streamer = function(
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/* function */input,
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/* function */output,
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/* int */interval,
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/* int */minimum,
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/* array */initialData
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){
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// summary
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// Streamer will take an input function that pushes N datapoints into a
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// queue, and will pass the next point in that queue out to an
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// output function at the passed interval; this way you can emulate
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// a constant buffered stream of data.
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// input: the function executed when the internal queue reaches minimumSize
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// output: the function executed on internal tick
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// interval: the interval in ms at which the output function is fired.
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// minimum: the minimum number of elements in the internal queue.
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var self = this;
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var queue = [];
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// public properties
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this.interval = interval || 1000;
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this.minimumSize = minimum || 10; // latency usually == interval * minimumSize
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this.inputFunction = input || function(q){ };
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this.outputFunction = output || function(point){ };
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// more setup
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var timer = new dojox.timing.Timer(this.interval);
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var tick = function(){
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self.onTick(self);
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if(queue.length < self.minimumSize){
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self.inputFunction(queue);
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}
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var obj = queue.shift();
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while(typeof(obj) == "undefined" && queue.length > 0){
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obj = queue.shift();
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}
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// check to see if the input function needs to be fired
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// stop before firing the output function
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// TODO: relegate this to the output function?
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if(typeof(obj) == "undefined"){
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self.stop();
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return;
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}
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// call the output function.
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self.outputFunction(obj);
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};
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this.setInterval = function(/* int */ms){
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// summary
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// sets the interval in milliseconds of the internal timer
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this.interval = ms;
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timer.setInterval(ms);
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};
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this.onTick = function(/* dojox.timing.Streamer */obj){ };
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// wrap the timer functions so that we can connect to them if needed.
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this.start = function(){
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// summary
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// starts the Streamer
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if(typeof(this.inputFunction) == "function" && typeof(this.outputFunction) == "function"){
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timer.start();
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return;
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}
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throw new Error("You cannot start a Streamer without an input and an output function.");
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};
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this.onStart = function(){ };
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this.stop = function(){
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// summary
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// stops the Streamer
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timer.stop();
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};
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this.onStop = function(){ };
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// finish initialization
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timer.onTick = this.tick;
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timer.onStart = this.onStart;
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timer.onStop = this.onStop;
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if(initialData){
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queue.concat(initialData);
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}
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};
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