It seems LinkedIn moved on tomcat !

after a long while i got myself on linked in site, as i got “Server spy” installed on my firefox browser, so i was getting the server name from the browser status menu.

anyway, today i found something different, actually “Server spy” said, linked in is using “Apache-Coyote/1.1″, as far i can remind, linked in was using sun application server previously.

i think it is really interesting, what led linked in to move over tomcat backed or tomcat based servlet container instead of sun application server?

anyway, if i find any info i would love to feed my blog

“শ্রম মিটার”, রিক্সা আর ঠেলা গাড়ির জন্য

আজ রিক্সায় করে আসার সময় ভাবলাম, কেমন হয় আমরা যদি রিক্সা ওয়ালাদের তার প্রাপ্পটা একটা যথাযথ নিয়মে দিতে পারি ?

ত ভাবলাম “শ্রম মিটার” এর ব্যপারে, “শ্রম মিটার” একটা সহজ সিস্টেম, যার কাজ হবে, রিক্সাওয়লার “কেলরি” আর “দুরত্ব” হিসাব করবে ।

এই ২টা হিসাবের মাধ্যমে বের হবে রিক্সার ভাড়া ।

একটা রাফ আইডিয়া, জানিনা কেমন হেব ।

AsyncServlet (JSR-315) proposed by Greg

Ajax based application is growing too fast, many frequent requests have to handle by application servers. this overhead is really one of the big concern to maintain ajax based application.

more over reading the instance reply is one of the biggest challenge. as all requests are asychronizely processed, so ajax based application send request to application server more frequent that it actually needs.

the good example can be a chat application or a system where we have frequent request to sync with our messaging or notification service.

thats what greg pointed to the JSR 315 proposal. if you already have heard about continuation i belief you have find some use case for using on your own ajax application.

the basic process in continuation is to send delay response. for example -

i had a ajax request, which is intended for receiving a bunch of incoming message from my application server. so my request won’t get disconnected unless they really have some data to notify me. in between this time my request thread will be in suspended mode. obviously you can apply certain timeout period.

following diagram show how a request cycle works -

the following part shows the event model, which is used to wake up suspended request before it becomes dead and time out request.

best wishes,

Struggling with open source jabber server

My on going project is based on jabber server. i was expecting following features from an open source jabber server implementation -

* Authentication, Authorization  and registration service must be taken from 3rd party. (here i am 3rd party)

* P2P and Group chatting

* HTTP Polling support (optionally  HTTP Binding support)

* Very scalable

* Very flexible user customization

* group messaging subscription

* group moderation role

also following features –  

* none blocking i/o

* optionally java based

* cluster support

thats all.

so after passing some hard time, i fought with “ejabberd”, the ERLang based jabber daemon. i must say this is the best open source implementation. (i didn’t test openfire).

the author really gave a lot of effort. i had a very bad time tough, i tried to invoke external authentication system. but i found php script but i couldn’t able to make it work.

anyway, still it didn’t full fill my requirement, i want to manage user A and A and Registration from my service.

secondly i gave a try Open-im, i show the source code and stuff, my first impression was very bad, i found it was stucking with an infinite loop. later traversing inside the code i found, it was because of the SSL socket initialization related code. code was seeking certificate to initiate a SSL socket. since i didn’t put any certificate it not suppose to do it.

anyway, after working with it i found, it is not complete even code were poorly written.

later i gave a try tigase, it seems very nice and very well written server. still i need my whole control over AA and Registration.

after stucking a lot, i am now cncerntrating on open-im, i am thinking to contribute on this project. first i will implement the following features -

1. move to spring framework

2. Refactor code base
2. move authentication based on JAAS

3. Support 3rd party profile service

4. Support none blocking I/O api

5. Support HTTP Pooling based on servlet container
thats all for now beside my other stuffs from my current project.

The technology-adoption & S-curve

Recently “emon.we4tech.com” has published a nice blog. here is the brief -

For last few day’s i was experiencing with “breakthrough” a book written by Mark Stefik and Barbara Stefik published by the MIT press. It was all about stories and strategies of Radical Innovation, technology markets that have declined dramatically since the late 1990s responding to the changing business climate. Very well described about breakthrough innovations that creates something new or satisfies a previously undiscovered need, launch new industries or transform existing ones.

And our capacity for creating breakthroughs depends on a combination of science, imagination & business; the next great waves of innovation will come from organizations that get this combination right.

Limit of maximum iterfaces per class.

I was reading through java doc for Proxy class. suddenly my eyes were stucked on the following lines of code – bit interesting perhaps,

The resulting proxy class must not exceed any limits imposed on classes by the virtual machine. For example, the VM may limit the number of interfaces that a class may implement to 65535; in that case, the size of the interfaces array must not exceed 65535.

CSS Hack only for IE 6

these days we got many browsers, sometime i feel if i were a king of the world i would love to eliminate all extra browsers. anyway, our designer bro (_ryan) and me were struggling to figure out some IE 6 specific hack. which won’t affect IE 7.x or other browsers.

we tried applying “@” prefix hack, for example: @width, but it worked on IE 6 and 7. so later we tried the old style “/* \*/” comment hack, exactly the same problem.

so suddenly our designer bhai (ryan), got a nice hack, it was “_”. for example: “_width: 22px”.

surprisingly it worked Wow on IE 6 without affecting IE 7 or other browsers. thanks allah, at least we found something that is working.

this blog is for those who are stucking with such problem.

best wishes,

JavaFX: How to run your HelloWorld

Today i have started learning JavaFX. so you will get my new learning over my blog site.

Problem how to run your first hello world FX:

there are 3 alternatives as far i know -
1. using NetBeans.
2. using Eclipse JavaFX plugin.
3. using manual execution

1. using net beans – you will find enough information from the starter example over here

https://openjfx.dev.java.net/Getting_Started_With_JavaFX.html

2. using eclipse plugin – install plugin from this url :
http://download.java.net/general/openjfx/plugins/eclipse/site.xml

3. using manual execution:
include 4 directory/jar over your classpath
i. javafxrt.jar
ii. swing-layout.jar
iii. Filters.jar
iv. your src directory (where you will store your *.fx) files

Main-class: net.java.javafx.FXShellyourPackage.ScriptFileName

best wishes,

ApacheDS – Directory Service

I knew about this project since it has started, but never felt interest to give it a try. so today at morning i just had it with my breakfast yammy yammy. it taste like sweat meat though bit fatty. it was really a great breakfast.

ApacheDS is using Spring IoC container. it seems more promising, i wrote the following configuration to let my “dc=escenic, dc=com” DN works .

(#) File: $APACHE_DS_HOME/conf/server.xml

—————————-

escenic

dc=escenic,dc=com

objectClass
ou
uid

objectClass: dcObject
objectClass: organization
dc: escenic
o: Escenic
description: Escenic content management system

Yet another configuration. let apacheds know about your new partition. this could be done adding a new property under “configuration” bean.

Thats all, it is working like shhhhhhhhhhhhh…..!!

best wishes,

struts rewrite, link rewrites url with “;jsessionid=” session id.

hi,
on my server i found some strange problem. it was actually related with tag. the problem was with the url rewriting, which was performed by struts tag library. struts tag library was creating an invalid URL.
for example i wrote the following code:
< img src=”my-image.gif” />

as i have only wrapped “${urlPrefix}” with in html:rewrite tag. so struts tag library wrote the following output.

which is totally a wrong url.

so how i resolved it?
very simple just fixing my weired code. now it looks like the following -
< img src=”" />

the generated output looks like -

here is a regex which may help you to find out the error tags:
“(.+)”

yeap it is working now