So how do we implement this feature ? By creating a processing function which will process each part in a loop. At each cycle, we will check if we have to yield. If so, we tells the scheduler to call us back when it wants to restart our process. If the process is done (10 parts processed) then we just returns.<\/p>\n

Here is how I will implement this “10 parts processing”.
\n[js]var partProcessed = 0;<\/p>\n

function executeYieldingTask() {<\/p>\n

\/\/ schedule some work
\n S.schedule(function myScheduledJob(jobInfo) {<\/p>\n

\/\/Process the 10 parts
\n while (partProcessed < 10) {<\/p>\n

\/\/check if I have to yield :new job with higher priority
\n \/\/ may have been scheduled
\n if (jobInfo.shouldYield) {<\/p>\n

\/\/tells the Scheduler to execute myScheduledJob
\n \/\/ when it’s done executing higher priority task
\n jobInfo.setWork(myScheduledJob);<\/p>\n

\/\/we yield so we exit the ‘process loop’
\n break;<\/p>\n

}
\n else {
\n \/* process the part partProcessed *\/
\n partProcessed = partProcessed + 1;
\n }
\n }
\n }, S.Priority.idle);
\n}<\/p>\n

[\/js]<\/p>\n

The IOwnerToken interface and how to use it<\/h3>\n

IOwnerToken is an interface which represents the owner of a job. By owner it means “master” : the one who controls and manage it.
\nA token can be set to multiple jobs at once and there is one function on this interface : cancelAll. This function simply cancel all the jobs owned by the token.<\/p>\n

To create a token, you have to call the createOwnerToken function. You can then assign it to created job.
\n[js]
\n\/\/create a token
\nvar ownerToken = WinJS.Utilities.Scheduler.createOwnerToken();<\/p>\n

\/\/create jobs
\nvar job1 = WinJS.Utilities.Scheduler.schedule( \/* …*\/);
\nvar job2 = WinJS.Utilities.Scheduler.schedule( \/* …*\/);<\/p>\n

\/\/Be in control
\njob1.owner = ownerToken ;
\njob2.owner = ownerToken ;<\/p>\n

\/\/Cancel the jobs at once :
\nownerToken.cancelAll();
\n[\/js]<\/p>\n

This token is then really useful when you want to manage a group of jobs at once.<\/b> Create an owner, if the user do something else, goes to another page : you cancel all the task at once and retrieve some CPU juice.<\/p>\n

Some useful functions<\/h3>\n

Now let’s discover some useful functions when playing with jobs and the scheduler. <\/p>\n

\n
• requestDrain<\/b> : use this function if you want to be sure that all scheduled jobs at a given priority are over. Simply pass the targeted priority, it returns a promise which can be use to know the completion of the “error state” of the queue processing <\/li>\n
• retrieveState<\/b> : you need to dump the schedule queue for debug purpose<\/strong> ? Use this function :). It dumps the name, the id, the priority of the tasks, etc.<\/li>\n
• schedulePromiseXXX<\/b> : there is a lot of functions with similar names(schedulePromiseAboveNormal, etc.). These functions takes a promise as a parameter. It assures that the completion\/error handler is processed on the scheduler with the given priority. If you want a completion handler tob be processed as soon as the promise is done, then use schedulePromiseHigh. <\/li>\n<\/ul>\n

  Here are some code example :
  \n[js]
  \n\/\/requestDrain example
  \nvar drainPromise = WinJS.Utilities.Scheduler.requestDrain(priority, name);<\/p>\n

  drainPromise.done(
  \n function complete(){console.log("queue drained");},
  \n function error(){ });<\/p>\n

  \/\/retrieveState example :
  \nvar S= WinJS.Utilities.Scheduler;
  \nS.schedule(function () {\/* *\/ }, S.Priority.aboveNormal,null,"a task name");
  \nS.schedule(function () {\/* *\/ }, S.Priority.idle,null, "infinite square name");
  \nS.schedule(function () {\/* *\/ }, S.Priority.belowNormal,null,"another task name");<\/p>\n

  var state = WinJS.Utilities.Scheduler.retrieveState();
  \n\/*
  \n state looks like this :
  \n Jobs:
  \n id: 22, priority: aboveNormal, name: a task name
  \n id: 24, priority: belowNormal, name: another task name
  \n id: 23, priority: idle, name: infinite square name
  \n\tDrain requests:
  \n None
  \n*\/<\/p>\n

  \/\/schedulePromiseXXX example
  \nvar dldPromise = WinJS.xhr({url:’www.infiniteSquare.com’});
  \nWinJS.Utilities.Scheduler.schedulePromiseHigh(dldPromise)
  \n .then(function(xhrResult){
  \n \/* process interesting content *\/
  \n });<\/p>\n

  [\/js]<\/p>\n

  Regards.<\/p>\n","protected":false},"excerpt":{"rendered":"

  Windows 8.1 comes with a new feature in the WinJS SDK : a scheduler. Let’s see what it is and how to use it! In Windows 8, every job is nearly done as soon as…<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[28],"tags":[14,15,30,34,25,53],"_links":{"self":[{"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/posts\/1471"}],"collection":[{"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/comments?post=1471"}],"version-history":[{"count":26,"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/posts\/1471\/revisions"}],"predecessor-version":[{"id":1498,"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/posts\/1471\/revisions\/1498"}],"wp:attachment":[{"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/media?parent=1471"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/categories?post=1471"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.jonathanantoine.com\/wp-json\/wp\/v2\/tags?post=1471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}