Continuous integration notification, the other way.

My team use Hudson for continuous integration it used to send mail to whoever commit.
Recently our handsome sysadmin decided that this is an abuse of the system so this option was blocked.

As a result i noticed from time to time that the build was broken for some time and i didn't love it very much, I assume no one love it.
I decided to improvise, Hudson  have plugin to gtalk so I created a gmail account for the builder and try this plugin.

Luck was not with me, the builder located in the lab on a private network so the plugin didn't worked.
However, Hudson have an option to send UDP package to a configured address as a result of a job state changed (job start, success or failed). so I configure Hudson to send my Linux machine notification about the build state.

Using Hudson REST API I was able to get all the missing information to send the needed data to the users who committed.
Since my machine connected to the web it was possible to start gtalk conversation quickly I wrote a Java program that send the users gtalk message using smack.
The result was beautiful the builder gtalk user start a conversation with the users that committed and report the build status.

Now for the last part, after I add an image to the gtalk user I was kind of attached to him, I was thinking it would be nice to talk with him from time to time, and then I remembered of my old friends from the university Eliza and Emacs Doctor.

The result is here: builder.webspace@gmail.com 
Here is a sample of our conversation

Just give it a try, open gtalk and chat with builder.webspace@gmail.com .
Barak.

Calling Java applet from Javascript

Hello.

Recently we were busy adding upload media to our webapp, it was required to upload large media files (more then 4G) from client browser to the main site while monitoring the progress. It was required that the user will be able to cancel downloads and have many possibly download running in parallel.

At first we tried to implement this using plupload which is flash client that use multi-part post, the sever side was implemented as Java servlet , this seems to works for small files but fail on large files, in addition memory was not free on some OS.

We next tried native html5 file upload that turn out to suffer with the same sickness, at the same time we noticed that jetty conent-length attibute is of type int and not long, that rules out both html5 upload and the multi part post approach.

Our last try was an FTP applet (based on our in house FTP client) that upload files to a Mina based FTP Server.
That turn out to be really successful, we let the applet handle the file choosing and the FTP to the server while keeping the UI in the Javascript side.
There were 2 things that gave us hard time while developing this applet.

• The first is the security, it turns out that even while the applet is fully signed and allow all security, it can not do that from a thread that was called from Javascript -- Oracle doc has only one short sentence about this property and it took us a while finding it.What we did is use the command pattern, having one thread created from the applet constructor, this threads allow to do all since it does not a thread created for Javascript command execution. A request from Javascript create a command that returns a Future, those commands than inserted into a queue to be processed by the thread created at the applet constructor.This seems to work well. Pay attention that you should not use Java Executors to implement this queue since Java Executors are lazy in its thread creation.
• The second issue related to the fact that embedding Java Applet in a page make the page load un responsive while the Java Plugin is loaded -- so we preferred to load the Applet dynamically the first time that the user try upload, this turn out to be tricky on Firefox on Mac and on IE you need to create a new IFrame for the applet, while in Firefox on Linux and Windows you can load the applet dynamically directly to your page.

The Applet Code code.

What is 'Level out the workload' in software development

Recently I been reading Taiichi Ohno book

Toyota Production System: Beyond Large-Scale Production

A key principles in his book was the principle of leveling out the workload

I have been reading lately lots of books that show how to apply Toyota Production principles to a software development process most of them describe how to map Toyota 7 waste to the software development world.

For example

• Inventory  ~ Partially Done work.
• Extra Processing ~ Extra Process.
• Overproduction ~ Extra Features.
• Transportation ~ Task Switching.
• Waiting   ~ Waiting
• Motion ~ Motion
• Defects ~ Defects

The meaning of leveling out the production in Toyota is to try to make every day the same amount of
each type of product.
For example:

If you have an order of 300 cars of types A and 600 Cars of type B each Cell should assembly
one car of type A than 2 cars of type B and so on.
According to the book leveling out the production help to maintain both machines and employee in good condition, where burst of actions and afterward long periods of doing nothing exhausted both humans and machines.

Another great benefit of leveling out the production is that it allow JIT, when working in JIT
you get every part from the earlier processes exactly when and where you need it, this enable single flow, reduce inventory and find defects early.

Now the question I was thinking of is, how do I level out the workload for software development ?

Software development is creative process unlike car production so maybe there is no good equivalence to leveling out the workload in software development.

My faith is that in software production the your best assets are your employs so leveling the workout can be mapped to:

• Invest and educate your employs.
• Give them feeling that their work is important.
• Provide them with ways to measuring their progress.
• Plan ahead to reduce burst of actions or periods of doing noting.

If you think there are other way of leveling out the production in software development, please let me know.

Testing YUI DND with Selenium

If you happen to write some selenium tests for YUI based page you may notice that sometime selenium DND does not work.
This is because selenium sometime has error when computing the right X,Y of a component when using YUI layout manager.
This problem can be solved easily by overriding selenium JavaScript code that compute X,Y given a locator.

For example getElementPositionTop can be rewrite to something like that:

Selenium.prototype.getElementPositionTop = function(locator) {
    /**
     * Retrieves the vertical position of an element
     *
     * @param locator an element locator pointing to an element OR an element itself
     * @return number of pixels from the edge of the frame.
     */
    var element;
    if ("string" == typeof locator) {
        element = selenium.browserbot.findElement(locator);
    }
    else {
        element = locator;
    }
    var xy = selenium.browserbot.getCurrentWindow().YAHOO.util.Dom.getXY(element);
    return xy[1];
};

All the change should written to a file for example 'user-extensions.js' and selenium should be run with the cmd:


java -jar selenium-server.jar  -userExtensions user-extensions.js

That should solve the issue.