Saurabh Jain

Generating free of cost

2010-05-06T14:23:00.000-07:00

http://www.fpdf.org/

Very useful for generating fancy table using PHP and that also free of cost.. :)
The other tool pdflib is not really good as it is costly... and some other php_pdf.dll thingy also causes issues as it is tough to find correct dll and generating dll from source requires to understand something into pecl...

Thanks
Suarabh

Generating PDF files from server side PHP..

2010-04-08T12:12:00.001-07:00

http://www.devarticles.com/c/a/PHP/Use-PHP-to-Create-Dynamic-pdf-Files/1/

http://articles.sitepoint.com/article/generate-pdfs-php

Working on it.. will update it later...

SJ

Excellent Dojo date poicker examples

2010-04-06T15:38:00.001-07:00

http://www.upscale.toronto.edu/test/dojo/tests/widget/test_DatePicker.html

Here is date picker with localization thingy supported...
using it now... :)

SJ

How to put lightbox on your website

2010-02-25T22:03:00.000-08:00

I did lightbox task using YUI once.. it took me two days to get that piece of code working... so i was bit apprehensive about light box....

then today i found this "ThickBox" thing which makes light box so easy that it seemed to me that there can be nothing simpler than this...

so first goes the link:
http://jquery.com/demo/thickbox/

Issues:
1. Light box does not capture the tab button....
2. It works on top of jQuery... so it might break with some other javascript library.. but fortuantely in my case Dojo + {ThickBox + Jquery} model worked perfectly..

I am glad it did as it reduced hour long task to seconds...

A small info to add.. this link is good for color coding things..
http://html-color-codes.info/

SJ

How to put Videos on your website

2010-02-25T22:00:00.000-08:00

This is very simple thing to do:
As usual, first i'll post the links which i found best and helped me in understanding the concept with ease...

This one gives the code snippet for scenarios when u have a video player and corresponding files to play...
http://www.sothinkmedia.com/guide/putvideo.htm

then other wonderful link is this one...
http://flowplayer.org/index.html
This made things lot easy .. the readme.txt and examples in downloaded zipped reduced the whole thing to just two lines...

SJ

Dynamic table creation using Javascript

2010-02-25T17:57:00.000-08:00

As u might know, i was struggling with Dojo Data grid and data table concepts...
so i decided to go back to basic...
I thought of implementing the table using normal DOM manipulation API like createElement, appendChild etc...

This particular link made my task a lot easy..

http://www.eggheadcafe.com/community/aspnet/3/83650/dynamic-creation--of-html.aspx
http://www.codeproject.com/KB/HTML/html.aspx

This gave me the basic code for create dynamic tables...
there were few bugs which i fixed ...
But it has a big drawback... I want my table to be wrapped in some kind of scrollable div so that in case i need to limit its height in future i can get it to work...

Let me see how to do that next.. Till then see yup/./

SJ

Dojo Data grid with JSON data

2010-02-24T18:41:00.000-08:00

Right now i am struggling with displaying with JSON data in DOJO grid on the front end..
Data can be either in a file... or returned as response to AJAX request.

Most helpful links:
For JSON as AJAX data.. This is more useful link than any but does not work for me...
http://blog.sonores.de/2008/03/14/dojo-tutorial-with-a-grid-part-3-english-version/

This one explains using DojoTable.. Though it is not that useful but still good to read after first one...
http://www.sitepen.com/blog/2007/11/06/simple-dojo-grids/

Problems i am facing are weird...
1. this.model is not defined...
2. Nothing is getting displayed and no error as well..
Confused what is the issue...
3. Styling related issues...

Will update you on this...

Problem statement CSS

2010-02-05T08:11:00.000-08:00

Hi, I have been struggling with this CSS issue for like infinite time now. Suddenly a thought came... As Swami Vivekanand has said "If you know your problem then you have solved it 90%"...
So here is my problem statement:
Without using table trick or absolute position and width parameter,
How to place div element of page in parallel to each other and over top of each other?

There will be one top div element where height and width can be defined but rest should be dealt in % and positioning concept.

Reason for not using absolute position and tabular structure is that i am doing internationalization so string length varies from language to language. If i use table and position then things get screwed from one language to other.
I am not sure if table less and positioning based thing will solve that problem but thats how i wish to do it.

Any one who read this problem statement, please respond to my problem.
Its like taking infinite time for me to solve this issue.

In the understanding of whole position and css thingy.. many links helped me a lot but one link specifically i would like to mention and that is:
http://www.barelyfitz.com/screencast/html-training/css/positioning/

SJ

Database handle in PHP-mysql

2010-01-29T08:52:00.000-08:00

This is the two line code i use to connect to database through PHP:

$dbhandle = mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

The great thing about this code is that once dbhandle is created then any call to mysql_connect will reuse the old dbhandle. This is very nice abstraction provided by PHP-mysql connector. I dont know if this is same with other connection object or not...

SJ

A brief on web related technology

2010-01-28T14:02:00.001-08:00

http://sharat.wordpress.com/
This page explains some of the web concept in brief ...
Some of them are useful...

SJ

After a month

2010-01-28T08:07:00.000-08:00

Sorry i was on vacation lately so had nothing much to post...

Recently i was working on database part of my project...
I had a doubt about auto-increment primary keys that what happen if some fields are deleted in future {which will happen in 99.99% of scenarios } then primary key does not remain sequential and those gaps will never be filled and eventually when project scale heavily then auto-increment field will reach its maximum and project will crash...

I discussed it with friend and in his opinion, auto-increment field is automatically taken care by the database so nothing to worry,... Moreover one should keep in practice to not write program to access primary key sequentially.

He also mentioned that i could use LDAPs for authentication of my system...
Will write rest later...

SJ

DOJO Charting and php mysql connection thingy

2009-12-27T10:59:00.001-08:00

yesterday i was trying to get my ajax-php-mysql code working..
Following are the problems that i faced...
1. I wanted to avoid call to mysql_connect method multiple times because in my perception, this would lead to multiple handles to database and hence wastage of resource and time... I was trying to save the handle of database in $_session variable but it was fruitless because i was getting server side error that database not connected ... then i checked documentation of mysql_connect and it says that if same arguments are passed then no new connection handle is created.... This can be great abstraction as PHP does the job for you.. but some inflexibility as well that it does not allowing me to have multiple connection to back end.... but i guess my knowledge is incomplete so will update this space regarding flexibility issue...

2. JSON object parsing...
we can use many inbuilt functions... My understanding of this is still vague... I was sending text/plain data from server and calling JSON.parse($data) thingy to convert it to JSON object but in some cases i saw that data was received in JSON format.. means it was converted into JSON on server side itself...
basically read the data from server and store it in {"" : [{"":"","":""},{"":"","":""}] } form....

3. Third problem was related to DOJo charts...
there is no way in dojo charts to create custom labels.. which is bad... because my RA guys would be mad about it...

4. Ajax.. PHP... MYSQL.. JSON...AJAX handling... this is the sequence of getting this done...

For dojo charting quickcet source is ...
http://www.sitepen.com/blog/2008/06/16/a-beginners-guide-to-dojo-charting-part-2-of-2/
first and second blog here... best

SJ

C pointers notes

2009-12-12T16:14:00.000-08:00

http://www.ibiblio.org/pub/languages/fortran/append-c.html

This is also good... read it whenever u are confused

Post about unix file system working

2009-12-10T23:48:00.000-08:00

http://people.csail.mit.edu/rinard/osnotes/h13.html

Read this some time in detail...

i18n support for images and variable size text

2009-12-07T16:29:00.000-08:00

http://www.alistapart.com/articles/slidingdoors/

I am struggling with i18n support thingy... so here it goes....

This page explains different ways of sending data between forms or pages...
1. URL
2. Form submit
3. Cookie transfer
http://www.plus2net.com/php_tutorial/variables2.php
SJ

transfering data from host to guest machine on virtual box

2009-12-06T13:45:00.000-08:00

I am stuck with this problem. I have Windows7 as host and Ubuntu as guest operating system. My wireless does not work on virtual box, neither the USB is detected. I tried to use the shared folder approach but that also throws error so i am basically handicapped due to this problem.
I tried to follows instruction given on this site but encountered error that "nautilus can not handle this kind of location". Totally stuck with no clue what to do...
Will update on how to fix this issue....

http://www.mydigitallife.info/2009/07/29/workaround-to-access-shared-folders-on-sun-xvm-virtualbox-from-windows-7-guest/

Comparison of RIP vs OSPF

2009-12-04T21:06:00.000-08:00

I thought of reading the in depth comparison of RIP and OSPF protocol.
RIP : Count to infinity problem, slow convergence, O(M*N) complexity where M is edges and N is number of nodes
To solve count to infinity approaches are hold down, split horizon but still there are other issues like no sub net masking support. All nodes in the network should use the same sub net mask, some frame related issues... Network size should be small .. Hope count is just 15 ... moreover packets between neighbors are exchanged every 30 seconds...

OSPF: Intelligent routing with improved alternative to RIP. Link state, Main problem is flooding in the network for sending updates but by using proper sub net masking support and carefully fine tuning the parameter, this can be bettered.

Full comparison is present on this site so please look here....
http://www.networkcomputing.com/unixworld/feature/002.html?cid=ref-true

SJ

Few things in Dojo

2009-11-30T14:55:00.000-08:00

I learned few things in DOJO:
1. Dojo.addonload(funcname)
this is similar to window.onload thingy... if we are using addonload thing then we should not use window.onload

2. dojo.query() I am yet to understand the basic flexibility that this provide...
However, it seemed useful while accessing dom element and defining events on them..
something like dojo.query("#idname").connect("onclick", function(){ });

3. Dojo.require is used to load the libraries

4. dojo.byId is similar to document.getHtmlById() or may be similar to document.getNodebyId() of javascript or DHTML

5. Dojo.connet is used for binding event with libraries...

Here is found a really well documented tutorial. I like well documented tutorial because they give a good head start...

http://www.dynamicajax.com/fr/AJAX_Chat_Usability_Additions-271_290_291_297.html
Chatting application in ajax... I should try this some time...

SJ

Css Style and my lessons

2009-11-28T14:16:00.000-08:00

I was playing around with layout, divs and css style properties.
Now it's always difficult to summarize all the experience but i'll try my best
This is what i learned...
1. Css wrapper div should be used to center the whole web site.
Now we should specify some width units and we browser size reduce beyond that value , then horizontal scroll bar will appear.
Also margin for this wrapper should be set to auto so that it'll be centered...
This code piece is used to center the website....

html,body {
height:100%;
margin:0;
padding:0;
text-align: center;
background-color: #999999;
}

#CenterLayout {
width: 1000px; /* set to desired width in px or percent */
height: 100%; /* This made me go nuts because i did not specify this height , Absolute value required here if vertical scrollbar is required below certain value*/
text-align: left; /* optionally you could use "justified" */
border: 0px; /* Changing this value will add lines around the centered area */
padding: 0;
margin: 0 auto;
}

2. Margin auto sets are outer padding values... In case of auto, it tries to place div at equal distance from left and right side div...

3. Float: left to make things left justified... i know this is not perfect... but i'll updated it as i learn more...

4. To put an image in the div and over lap text on it... i wrote this style

#CenterLayout #TitleSection {
position: relative;
top:0%;
left:30px;
width:50%;
height:25%;
// border:5px double #999;
margin:0 auto;
}

#CenterLayout #TitleSection #Title-background {
width:100%;
height:100%;
}

#CenterLayout #TitleSection #TitleContent{
position: absolute;
//margin: 15px 15px 15px 15px; /* No Idea about significance of this */
// border:3px double #777;
padding-bottom: 5px;
bottom: 0px;
left: 0.5em;
width: 90%;
height: 50%;
font-weight: bold;
color: #777;
//font-size: X-large;
font-size: 150%;
overflow: hidden;
text-align: center;
letter-spacing: 8px;
}

Now important point here is positioning attribute.
Position: absolute, place the div at absolute position relative to parent container.. so for this, we need to make sure parent container's width and height property. Also when we specify, absolute position then top, right, left, bottom... some of these properties should be specified properly.

If position is relative then top and left values are relative to self absolute position.

One very important thing to learn about vertical image resizing is:
1. in case of horizontal, screen appear in center and margins are left on both side, this looks ok because things are symmetric and space is filled. Note: here we set height as 100%

2. Now if we re-size the browser vertically then things can go messy, for example: text overflow can occur. To avoid this, we should specify the height dimension also to some value..
suppose u have an image and u position some text on top of it...
by horizontal width property of parent div, scroll-bar will appear and things will not go wrong.
This boils down to two things:
1. If we specify height dimension to some value then on very large browser window, we might see some blank space below the website ...
2. If we do not specify height dimension to 100% value, we need to find some way so that when image is resized while browser resizing then font that is overlapped on the image should also be resized...

Will write later...
SJ

Css layout and positioning

2009-11-28T02:00:00.001-08:00

I was again struggling with the css layout of my project page...
Finally by hook and crook , i got something running and this link helped me a lot in the process...

http://www.barelyfitz.com/screencast/html-training/css/positioning/

CSS styling thingy, importance of fixed, relative and absolute positioning..

SJ

Internationalization and charting

2009-11-27T12:54:00.000-08:00

I was searching for some java script toolkit which support Internationalization as well as charting support. I searched on internet and found this page...

http://kauriproject.org/wiki/g1/g4/g2/69-kauri.html
This page gives a brief overview of major JavaScript tool-kits in the market.
It covered negatives well but it did not distinguish deeper into their positives.

Finally i decided to go for DOJO toolkit as it is the one which charts as well as i18n support.

SJ

Java, C++, C and web programming

2009-11-26T10:36:00.000-08:00

Nowdays i am coding in so many things that i just mix up things badly.
to overcome this situation, i should take test from time to time..
so here i go for Java:

http://cyber.gwc.cccd.edu/faculty/hcohen/Java5Ch11MCAnswers.txt

SJ

Common mistake while allocating pointers and good programming practice

2009-11-26T09:24:00.000-08:00

http://www.eskimo.com/~scs/cclass/int/sx7.html

Malloc may fail so it is always good to check the return value of malloc and then proceed..
One can also write a wrapper function to malloc which return space allocated to void pointer. We just need to type case this to desired data type..

SJ

stack vs heap allocation

2009-11-25T22:00:00.001-08:00

A very frequent and obvious question to mind...
what are different segments and from where storage is taken to assign space to variables...

Code segment --- compiled code, static link files etc..
Data segment -- stack and heap
stack --> function calls and variables with in function... main is also a function
heap --> static and global variables

Now big question is:
How does memory leak happens...
Suppose i define some variables in a function,
variables allocated memory in stack,
and when function call returns then all that memory is de-allocated..
By de-allocation means top pointer of stack returns to point to callee function.

Now if i do not free that variable space and set the content of memory location to null then that might be disaster because it'll result into memory leak but i dont understand why did memory leak happens... Which variable is holding that memory.. Where the pointer variable allocated memory from

Will freshen up my concept and then updated this stuff...
till then u read this...
http://ee.hawaii.edu/~tep/EE160/Book/chap14/subsection2.1.1.8.html

Recently added features in java

2009-11-25T06:40:00.001-08:00

These are some recently added feature in java's new version

Strings in switch is the interesting one....
http://code.joejag.com/2009/new-language-features-in-java-7/

css sytle, three column layout and float property

2009-11-24T15:30:00.000-08:00

http://webdesign.about.com/od/csstutorials/ss/css_layout_sbs_9.htm

This link is really useful in understanding three column layout but bad thing is that it hard code the div size instead of using %..

Some good tips for newbies...
http://webdesign.about.com/od/layout/a/aa062104.htm

Fixed vs liquid layouts..
http://webdesign.about.com/od/layout/i/aa060506_2.htm

Excellent tutorial on centering a web page layout...
http://blogs.techrepublic.com.com/howdoi/?p=186
http://www.wikihow.com/Center-Web-Page-Content-Using-CSS

One doubt still remains and that is how to get away with fixed width parameter and use percentage in whole of the page...

SJ

Globbing a directory in perl

2009-11-22T20:19:00.001-08:00

To glob a directory is very simple in Perl.
We just have to use these three lines of code...

#!/usr/bin/perl -w

@files =
# FILEPATH can be like *
# for all html files it can be /var/doc/*.html

foreach $filename (@files){
open FILE, "<$filename" or die $!;
# do my 50 things
close FILE
}

Bug algorithm on robot... Difficulties on running on actual robot..

2009-11-18T08:08:00.000-08:00

It was way more difficult and frustrating then we (Me and Konrad) initially thought.
The major problems and issues that we faced are summarized below:

1. Specifying laser driver in .cfg file

2. Timeout problem .. Laser takes time in starting
red and green light issue

3. Serial port issues...
Identifying which port on serial device.. laser is sending the output

4. Inserting the USB in correct side.. because one USB port is for serial tty/USB0 - tty/USB3 and other is for 4 to 7

5. Robot battery low so some time output is not returned well.. Make sure above 10V

6. Software related measurement issues:
a. Rotating more than desired angle
so for this we had to decrease the turnrate as it was reaching near to desired rotation value... also after it stops rotating we were checking if we need to rotate in opposite direction to get exact rotation...

b. Laser not returning data and some time data is not that accurate...

c. On stage things are simple but pioneer was behaving in lot more erratic way due to extra rotation and movement related problem... we had an accuracy of 66% in our case. when robot follows the wall accurately.

d. Path on stage was way different from actual pioneer because actual pioneer had lot of extra rotation and extra steps kind of problem... on stage it was more smooth path than on actual pioneer... We calibrated lot of variables in movement related to exact positioning and used those error correction parameters in the code...

so for example... while checking slope or distance from a point... we had to use some error value and anything lying between expected output - error value was taken as right value or condition fulfillment

After all this.. our robot does not work correctly in all the scenarios but it executes the wall following well in most of the cases...

Problem was also that there was never enough space to carry out this experiment. even if we take obstacle or wall detection distance to 1.0 meter then robot starting sensing other things because in the path their was alwyas things falling within that space...

If we give less than that then robot some time gets too close to the wall and while rotating and moving further, it collides with the wall..

Will post more difficulties later...

Embedding anything into the web site

2009-11-17T15:40:00.000-08:00

This seems to be really nice page...
Informative too... read in detail some time...

http://www.labnol.org/internet/how-to-embed-in-html-webpages/6365/

SJ

PHP based login form code and style sheet issues

2009-11-17T15:17:00.000-08:00

1. I was trying to setup login mechanism in my PHP based mechanism.
for this, i thought of using direct code from internet.
i found this code snippet to be really straightforward.

http://www.phpeasystep.com/phptu/6.html

2. This took my lot of time. I wanted to stretch my image in such a way that it fits to the window and on resizing, it should not create any issues.

Idea was to create two div and use image tag in one of the div. set the z-index to -1
Do the regular stuff in other div and set z-index as +1. there are few other things like padding and position that we need to take care so for that i copied the code from this site....
http://www.quackit.com/html/codes/html_stretch_background_image.cfm

SJ

php select problem...

2009-11-16T09:37:00.000-08:00

First thing...
if sql code is not working then wants to see the output then first go to php directory and from command line say some thing like this:

php.exe

this will through the error and u can fix it accordingly...
if we call from browser then there is no way to find the error message..

second is:
Use "" quotes while forming html string and '' while forming sql string.
i am not sure if this is the rule that should be followed to fix my problem but this is the way it works...

SJ

WAMP setup

2009-11-16T07:24:00.000-08:00

For a while i was struggling with wamp setup.
The problem was that PHP-mysql connection was not working properly.

I followed instruction on this page to set things up for me.
http://www.devarticles.com/c/a/Apache/Installing-PHP-under-Windows/5/
http://httpd.apache.org/docs/1.3/windows.html#down
http://forums.mysql.com/read.php?52,69846,69846#msg-69846

The problem was that i had not un-commented php-mysql connection lines in the php.ini file located in apache2.2 folder in program files..

SJ

CEGUI skinning

2009-11-15T14:46:00.000-08:00

I had this problem of not able to align text properly on top of button in vanilla skin of cegui. I decided to switch to taharezlook as it provides more options for windowing as well as text alignment property.

This was seriously tricky. I was in no mood to read that tutorial so just jumped into data files to see what can be done.
CEGUI follows a layering based approach for any widget.
General CEGUI widget looknfeel looks likes this:

.
.

use the properties value

.
more layers
.
.

CEGUI also provides controlProperties which helps in hiding some of imagery section and make other accessible...

By this way, i separated the logic of default image and custom image of button in taharez look and without using imagebutton thingy, i achieved "text on top of image acting as a button" functionality.

Now i am starting with WAMP model.. my first major foray in PHP.. till now i used to work on j2ee....
--Saurabh

Internal working of a router

2009-11-11T09:18:00.000-08:00

This page explains the internal working of a router...
I remember reading once but was not able to find the page... so here it is..
http://www.erg.abdn.ac.uk/users/gorry/eg3567/inet-pages/router-opn.html

Thoroughly explains the internals...

Interfaces vs abstarct classes

2009-11-08T15:39:00.001-08:00

This page gives a very nice and detailed discussion on interfaces and abstract classes...

http://mindprod.com/jgloss/interfacevsabstract.html

SJ

Color recognition using openCV

2009-11-06T22:53:00.000-08:00

Nowdays, i am working on sonar sensors and color detection problem using openCV...
For sonar sensors...
-> In built support for pioneer robots..
-> Problem at corners
-> Range generally 15-20 m
-> Use sound waves

For OpenCV based image capturing and recognition ...
I am still wondering on how to proceed on this... My sub task is to mount camera on robot, take pictures of object, trigger the color detection code and take appropriate action.

Will post more on this as i learn more details...

SJ

cegui ogre and theora plugin work

2009-10-30T16:59:00.000-07:00

For past few days, i was struggling with cegui theora and ogre plugin work. Today i got it working with help from Vamsi...

This documentation is for windows operating system. I specifically tried on window XP but i am not sure if this work on other versions or not. However if we have operating system compatible libraries for each required component of setup then we can hope that it'll work.

First we should get OGRE installed on the machine. Set the (OGRE_HOME) variable.
Get the CEGUI setup working on machine. So make sure that CEGUI and OGRE based dll and lib files are present on the system. If possible, try one CEGUI-OGRE based hello world kind of program.... This is an appropriate application to start and test OGRE and CEGUI...

http://www.ogre3d.org/wiki/index.php/Basic_Tutorial_7

Once we have CEGUI and OGRE working then open this page and try to compile the theora-videoplugin...

The bad part about this video plug-in is that there is very less to no documentation available on internet...

For compiling.. Following points need to be kept in mind...
1. Create a folder TheoraPluginThingy
2. cd into the folder

[...All steps in this "TheoraPluginThingy" directory...]
1. Get libogg
2. Get libtheora
3. Get libvorbis
4. Get ptypes
5. Install tortoiseSVN [if you don't have] and get the Theora-Videoplugin code

Start with libogg...
Search for dynamic solution file and compile it...
Check for the size of .dll created in output directory... This directory is set in properties... so check there...

Now cd to libvorbis directory
Search for dynamic solution file and compile it...
There is a readme file so dont forget to read that..
Also you may need to correctly specify the version of "libogg" that you use in file "libogg.vsprops".

Now one problem here is with file vorbis.def...
In this file you may need to modify one line...
_analysis_always_output One may need to put a semicolon before this line...

Now cd to libtheora directory
Search for dynamic solution file and compile it...
Don't forget to read the readme file and set the versions of both libogg and libvorbis in the corresponding .vsprops files...

Also one file lib/theora.def might be missing so get it from this location http://svn.xiph.org/trunk/theora/lib/theora.def

Now enter the ptypes folder and create a static multi-threaded library...
for this.. there are multiple solution files so pick ptypes_lib and compile and build it... Check for generated static lib in output folder...

In project settings.. make sure that in configuration properties... it is set to static lib
and C++/code generation is set to "multithreaded dll"

Now follow the instruction on the "theoraplugin" compilation web page and copy all the includes, dll and lib files to appropriate locations...
also copy ogremain.lib and ceguibase.lib files to appropriate folder in TheoraVideoPLugin folders lib directory...

Now change the project setting and include the Ogre_home/include location as well...
Mine looks like this... for all for solution files ....
..\..\TheoraVideoPlugin\include;..\include;"$(OGRE_HOME)\include";"$(OGRE_HOME)\samples\include"

Now theoraplugin dll will be ready after compiling....

Now to run the demos in demos/player folder...
Check the properties...
Change the resources.cfg file.... put it at appropriate location..
points to media folder at appropriate place...
Change the plugins.cfg file and get TheoraVideoPlugin and other dlls like libogg, libhteora and libvorbis..
Run the application... Debug a little and read the log files generated ...

Hopefully this will make your things work....

Will refine this draft later... SJ

password problem for ubuntu

2009-10-28T16:19:00.000-07:00

I remember once i forgot my ubuntu password and because i was not aware of hacking fixes so i had to reinstall my OS. I was thinking about that and found this useful forum page which explains in detail that how vulnerable are Unix and Windows machine to hackers.... and how important it is to set a grub password...

http://ubuntuforums.org/archive/index.php/t-3609.html

cl : Command line error D8003 : missing source filename

2009-10-27T16:43:00.000-07:00

This error was coming because i misplaced a quote around library inclusion in the properties window of the project.
Wasted my 35 precious mins...

SJ

CEGUI OGRE THEORA

2009-10-25T18:03:00.000-07:00

This link will help in cracking some of the issues that i am facing.
http://www.wreckedgames.com/forum/index.php/topic,894.0.html

This will also help in basic setup...
http://www.cegui.org.uk/phpBB2/viewtopic.php?f=4&t=154&start=15

Next thing is to download ogg, vorbis, theora, ptypes and theora video plugin...

Do a static build for each of them in the order... and get basic theora set up ready..
If this much work is done then i can focus on rest...

SJ

Stuck with OGRE-CEGUI-Theora plugin...

2009-10-25T08:13:00.000-07:00

Nowdays i am stuck with OGRE-CEGUI and theora plugin....
There is no explicit documentation available....

Seems to render the video, i need to extract the video texture and audio texture of the file... Once i have that then i need to load the material to render that texture...

Once i render it, it should run... Will try once more and then will write the tutorial...

till than njoy.... deadline... tomorrow... wuhuhuhuhu

Some java concepts:

2009-10-22T22:57:00.001-07:00

Purpose of defining the constructor private:

1. To make the class singleton
2. Making constructor private will not allow any other class to make object of this class or in other words, this class can not be sub classed...

Virtual memory

2009-10-20T19:48:00.002-07:00

I found this link to be very concise and beutiful.
http://williamstallings.com/Extras/OS-Notes/h9.html

Read in detail sometime..

Thanks

Problem fixes...

2009-10-12T20:38:00.000-07:00

Nowdays i am not frequently logging all my problems...
so lets do it now...

1. .player file generated in player-client assignment of robotics class...
I worked with Makefile. Problem was that initially i was using eclipse C++ plugin to program all the stuff.. i had to put libraries for compilation and linking so i was not adding linker library or may be the path was wrong.. I tried many things and one of them worked.. Basically point was to look into all the properties of building and change some things in compile and linker... in compile i was supposed to add the path and same with linker .. somewhere i was also supposed to specify .so file name....

Apart from this... i was supposed to find that where those files exists in the system so for that use of pkg-lib command was handy...

Second .. once i removed ported my project to department machine then i was supposed to change entries in makefiles....
so for that i used pkg-lib command to bring all the libraries...
then i used -I flag in makefile compile thing....

once i'll see it again.. i will recall exact syntax...

Now i am stuck with CEGUI and OGRE work of my RA....

Thanks
SJ

Significance of virtual destructors...

2009-10-10T14:02:00.000-07:00

Earlier i thought that virtual destructor are used to make sure that all the data pointers, memory blocks are freed when object gos out of scope...

But the actual significance of virtual keyword is that it allows the derived classes to override the base class destructors... this way when we delete the object of derived class at the end of all our work then derived class destructor is also called...

This link explains this better...
http://www.codersource.net/cpp_virtual_destructors.html

Player - Stage work

2009-10-03T09:24:00.000-07:00

I am totally stuck with this player/stage thingy...
Trying to work on my assignment of robotics where i need to move a robot on a plane while avoiding all the obstacles...
Just wondering how would i get the world information...

1. May be some way to read from world file... but not able to find any API to read from world file or finding the obstacle information...

2. Passing separate file which specify the environment... Logically this idea is offensive... so not possible...

3. Using sensor... Dont know how would this work.. This seems to be the ideal solution to my problem...
Let me try this...

C++ vs Java

2009-10-02T15:45:00.000-07:00

Java-- garbage collection..
C++ no collection...

Java-- No virtual keyword.. Java has equivalent final keyword but notion is opposite...
i mean in java we have to explicitly say final but in C++ we explicitly say virtual....
[credit.. Will]
C++ Virtual keyword

Java-- Package
C++ Namespace

Java-- No operator based polymorphism
C++ Polymorphism

Many other.... will write later... Tried a bit now...

Priority Queue discussion...

2009-09-26T20:35:00.000-07:00

Priority queues are really important data structure in operating systems and network.
In operating systems it is used in scheduler for scheduling process according to their priorities... while in networks in it used to schedule packets of different protocols for scheduling the packets...

Priority Scheduling packet... http://en.wikipedia.org/wiki/Priority_queue

Saurabh

Comprehensive list of Algos questions..

2009-09-26T17:40:00.000-07:00

Apart from reading the list and question that you have already..
Just look at these questions.. Some of them are good...

http://inder-gnu.blogspot.com/2007/03/detecting-and-fixing-linked-lists-loops.html

Get started with basic Latex

2009-09-26T17:01:00.000-07:00

Recently i had to write a report in latex.
Started as following:

1. Installed latex on ubuntu...
sudo apt-get install latex

2. Installed a pdf reader on Ubuntu..
i chose to install xpdf for this purpose.

After this to test the latex thing..
vi firstExercise.latex

Opened up a file:
\documentclass[11pt]{article}
\begin{document}
This is the tex file...
\end{document}

!wq

To convert this latex to .pdf extension...
>>latex firstExercise.latex
This creates a .dvi file...

>>dvips -Ppdf -G0 -f -o firstExercise.ps firstExercise.dvi
This creates a .ps file...

>>ps2pdf firstExercise.ps firstExercise.pdf
This creates a .pdf file...

Read this file using xpdf...
We can view this file and feel happy and excited about putting our first step in Latex world...

Saurabh

Visual C++ application

2009-09-14T09:34:00.000-07:00

'MessageBoxW' : cannot convert parameter 2 from 'const char *' to 'LPCWSTR'

Solution to this is to change the character set to multi-byte character in project properties.

I encountered this while trying to run some basic application on OGRE....

Arithmetic Operation allowed on pointer

2009-09-13T09:14:00.000-07:00

Only arithmetic operation allowed on Pointers us:
1. Addition of integers to array address
2. Subtraction from another pointer

No other operation is allowed. For instance division, Multiplication and addition is not allowed.

Installtion of OGRE and Visual studio setup

2009-09-11T16:05:00.002-07:00

1. Visual studio setup-08

Go to dreamspark.com
Create account
Get the key
Install download manager
Download the Visual studio professional edition
Run the "autorun.exe" utility

I wasted my lot of time due to not using download manager.

2. Download the prebuilt SDK of OGRE from their site. Run it and install at some file path which does not include spaces.

3. Download OGRE wizard. This helps in some situations like having an OGRE SDK option on your "new project" link.
Try running this. This might be useful.

4. Setup a new project and run it. Be careful about the properties setting.

Will post later...

Will also try to install CEGUI thing tonight... so tonight is going to be the installation night... or may be tomorrow morning.
Let's see what productive thing i can do today.

OGRE, Visual studio and CEGUI

2009-09-11T16:05:00.001-07:00

Today i spent whole day on setting up OGRE and Visual studio on my account.
This was highly frustrating experience. I am a Java developer and usually prefer Eclipse as my IDE. Eclipse is really simple and intutive in its setting. I found Visual studio to be highly complex and ridiculous at some points.

Just to mention, whenever i create a new project my old projects are automatically closed. If i want to keep both of them open then i need to put them in same solution scope which is poor. Moreover all the files are dumped in the same folder and i need to create folder in the actual disc location to put some structure to the application.
I don't see the use of filters as they just get flat when i open the actual project location.

Will keep you posted on this.

Cabinate files .. Invoking local files from Html page

2009-09-11T16:04:00.001-07:00

I was stuck at work as i had to find some way so that i can execute local file system files from the application running in web browser.
started googling and my collugue stumbled across the concept of .cab file and Object tag in html page. As brwoser just understands few mime-type so i was not sure if it can execute some exeutable present on file system. I thought it might have security concerns and brwoser might not support that MIME type but we found that browser has this octet-stream mime type which can be used to execute the .cab file.

MSDN provide some platform SDK which can generate .cab file for set of executable. That can be used to generate .cab file. In order to run that file from browser, we need to change the browser's security settings. Browser's security settings can be changed or .cab file can be signed by using certificate generater program. One such program was also provided by microsoft MSDN library.

Finally we were able to generate cab file and execute a local file system application from a button click on HTML page.

This explains the JSP and form processing well

2009-09-08T08:38:00.000-07:00

http://www.j2ee.me/products/jsp/html/jspbasics.fm2.html

Rest later

Strut Spring Hibernate and delegation pattern

2009-09-05T21:32:00.000-07:00

I am reading about delegation pattern today...
Delegation pattern is used when a class A expresses some behavior or exposes some functionality using some API's but actual implementation is delegated to classes behind this class A. This enables putting one more layer between the classes.

Class A also provides API's so the client code which uses instantiate class A can also choose which supporting class functionality it should choose.

Wiki page has nice description on this with example:
http://en.wikipedia.org/wiki/Delegation_pattern

Second pattern that i was reading today was DAO pattern.
This pattern allows independence of data access resource mechanism and client side code. In raw terms, if back end resource changes then client side code should not be modified.

This page describes it best. http://java.sun.com/blueprints/patterns/DAO.html

Rest later

Internationalization in a web application

2009-09-03T08:43:00.000-07:00

Two methods:
First to have each page in all supported languages.
Useful when whole web application needs to be internationalized.
A Servlet controller will pick the right page after extracting the browser/request locale settings.

Second is to use resource bundles where single page is maintained but part of page which needs to be internationalized is maintained as resource bundles..

Reading about XFS file system + AVL tree algo

2009-08-31T20:40:00.000-07:00

XFS file system uses Journal file systems approach. Journal approach allows XFS to keep file consistent even in the event of crash...
The main approach is to write all file update related operation in a circular buffer (Journal)... This journal will never be read during normal file read operations. If system crashes then we can use that jorunal memory to keep file system consistent.

Second, AVL tree came into existance because in case of sorted data insertion in Binary search tree, it takes O(N) time... so balanced search tree approach was used so that O(logn) time insertion can be done...

SJ

List of some paper that i read recently.....

2009-08-28T15:28:00.000-07:00

Related prof. jon weissman research:

Resource Bundles: Using aggregation for statistical wide-area resource discovery and allocation

SIP-based Voip traffic behavious profiling and its applications

Practical techniques for eliminating storage of Deleted Data

Exploiting Heterogenity for collecive data downloading in volunteer based networks

Adaptive reputation-based scheduling on unreliable distributed infrastructure

Ridge: Combining reliability and performance in open grid platforms

Exploiting the throughput-fairness tradeoff of dealine scheduling oin heterogenous computing envieonments

Co-designing the failure analysis and monitoring of large scale systems

Times now...

2009-08-27T20:14:00.000-07:00

Presently i am facing the most exciting , challenging and uncertain phase of my career...
In order to follow the heart, i am killing my opportunities, ignoring avenues...
Lost in thoughts and time, i am

Will complete it later...

KMP, Boyce moor and brute force

2009-08-23T12:01:00.000-07:00

I was revising my concept on these algorithm....
Once i was master of algo but after staying out of touch lately, i feel my algorithm skills have gone blunt....
here i jump back...
KMP:
Practical Use: In reading data from network streams and large files...
More fruitful when alphabates are small...
It is claimed to be faster if mismatch occurs later in the series...
Prefix-suffix approach. Each alphabate of pattern to be searched is just traversed once.

Boyce moor:
Practical Use: Faster when alphabates are large and slow when alphabates are small...
Back-traversal based appraoch.

Brute force:
Practical Use: Poor for binary usage...
just O(n*m) solution...

Rabin carp:
Practical Use: Hashing function based approach...
Efficiency depends on hash functions quality...

This is my favorite read...

2009-08-18T13:14:00.001-07:00

http://intellibriefs.blogspot.com/2007/06/indian-intelligence-another-sneak-peek.html

Indian Intelligence...

Java vs C++ .. for programmers

2009-08-12T22:12:00.000-07:00

http://www.javacoffeebreak.com/articles/thinkinginjava/comparingc++andjava.html

This site lists detailed differences between java and c++

Footbal game design in Java

2009-08-12T21:33:00.000-07:00

Classes:

public class Player{

/**
Personal Information
*/
protected String _name;
protected String _address;
protected String _bloodGroup;
protected String _age;
protected String _sex;

/**
Game related Information
*/
protected Team _team;
protected Position _position;
protected Vector neighborList;

}

public class ball{
protected Position _position;
protected Player _possesion;

public void kickBall(force x, angle y){

}

public void changePosition(position x, position y){
// move from position x to position y
}

public void drawTrajectory(){

}

public boolean isGoal(){

}

public boolean isValidGoal(){

}

public void pass(Player x, Player Y){

}

}

Think more on the API's of this game.

When to use b tree and when b+ tree

2009-08-12T21:08:00.001-07:00

B trees are specifically used when we need to seek the data... In case of b trees, frequently seeked data can be moved up in the tree so that next time less number of access or look ups would be required.

B+ trees are used when we need to do full scan. Some other advantage of B+ trees is that high fanout, less seeks required as more pointers are available for data lookup which is in contrast to B tree where intermediate nodes stores data values which waste the look up pointer space.

In B+ tree, leaf nodes are connected as linked list which makes it easier to traverse.
Also in B+ tree, depth of the tree is small and a uniform implementation can be achieved as non-leaf nodes acts as indexes and leaf nodes acts as data holder...

Practically... indexes can be placed in the cache while actual data can be placed in the hard disk.

For detailed analysis:
http://stackoverflow.com/questions/870218/b-trees-b-trees-difference

Also look into wikipedia articles on addition, deletion of nodes...

Static binding vs Dynamic biding..

2009-08-12T20:53:00.001-07:00

http://geekexplains.blogspot.com/2008/06/dynamic-binding-vs-static-binding-in.html

This page explains the difference of static binding and dynamic binding in java...
To summarize:
All the instance method calls are resolved at runtime so that is dynamic binding.
All the static method calls are resolved at compile time so it is static binding.

As the static methods are resolved at the compile time so it is not possible to override them.
As java does not allow polymorphism so all the member functions are resolved at compile time only.

Similarly private methods are resolved at compile time only as they are never inherited..

JSP notes

2009-08-07T18:49:00.000-07:00

Just now i cam across few of good JSP tags:

1.
2.
3. <%@ errorpage=pagename />
4. <%@ iserrorpage>

This page explains the basics of main jsp tags:
http://www.geocities.com/srcsinc/java/java_tutorials/jsp_tutorials/jsp_tutorial_6.html

Using log4J class in your code...

2009-08-07T13:13:00.000-07:00

This page describe th importance and usage of log4J library.
It's a strong library with wonderful utility like logging levels and logging inside threads...

http://www.avajava.com/tutorials/lessons/what-is-log4j-and-how-do-i-use-it.html?page=2

Read this page for more details..

Make your code rebust and professional

2009-08-04T14:34:00.000-07:00

I learned about how to divide code into components and how thinking little before coding helps in good design and fast work.

Using logger module and using separate error module in the system helps in making code good.
Use a file like errorConstants and define all the error messages in a hashmap.

Define this hashmap as a static object. Declare a custom exception and define some constructor

To be completed later....

Factory Pattern, Visitor pattern, Aspect oriented programming and spring framework

2009-07-31T08:51:00.000-07:00

Today i read wikipedia articles about visitor pattern and factory pattern...

Factory pattern is useful when u don't know the type of object that you are invoking..
You separate the logic of identifying the object type and invoking the desired method on that object type in factory class.

Basically term factory method means any method that creates objects. Whenever u wish to invoke the object, u create the factory class object and pass the information to this class which figures out and invoke appropriate object.

Visitor pattern:
Suppose there are four components in the system and all of them have common method like print or run or act... so instead of doing a implementation of common method in each of the subclass, a new interface is defined which declare common method for each component. A new class which extend to this interface implements the component specific functionality in class code. This way we separate the code of common method from sub classes.

Aspect oriented programming:
The piece of code on wiki gives a wonderful insight into this. Suppose u have bank transaction code. Here a method transfer money from one account to another. For sake of security and system services like logging and database transaction, a lot of checks will be introduced in the code. This is bad because in future if logging functionality changes or security changes then transaction code will have to be changed. This leads to cross cutting concerns. cross cutting means the logging module is cutting across other module so it creates problems. To avoid this aspectJ should be used. In this all the cross cutting code is specified in a separate file as aspect. This file defined the join point and point cuts which helps in separating code.

Spring framework:
Powerful framework with lot of features. Yet to understand it's role in j2ee applications fully.

SJ

Reading and writing files in java

2009-07-31T07:39:00.000-07:00

I always forget the exact syntax of lines in java for reading and writing files...

Reading files:
Convert the file to inputstream or outstream and then read or write to the file using streamReader or streamWriter...

Create the fileReader from the file and read that fileReader using bufferedReader

Use scanner to read file by line by line...

Communication between JSP and Servlets

2009-07-30T20:28:00.001-07:00

getServletConfig().getServletContext().getRequestDispatcher(”jspfilepathtoforward”).forward(request, response)

Deep copy vs Shallow copy

2009-07-30T20:12:00.001-07:00

If the object is having any pointer then deep copy is preferred because in case of shallow copy, if pointer is changed or object is destroyed then dangling pointer problem may arise.

Wonderful post on pass by reference and pass by value confusion of Java
http://www.javaworld.com/javaworld/javaqa/2000-05/03-qa-0526-pass.html

Values of reference is passed by address and reference itself is passed by value.

Abstraction vs Interfaces

2009-07-30T19:17:00.000-07:00

Abstraction: Default implementation of set of methods.
Compulsive use of extends variable and overriding of default functionality
Better to be used in application framework where a default implementation is required in case component does not implement their own. Like event handling service, Messaging service etc..
If variables changes often then use abstraction

Interfaces: Abstract methods and final variable
Provide conceptual structure to whole application.
Allow Multiple inheritance
If methods are changed frequently then use interfaces.

For example: Interfaces/ Need for multiple inheritance

Two kind of people: actor / director ..
for each of them we define one interface but now what if there is third kind for people who are both actors and directors....

In such scenario we need multiple inheritance...

Need fr abstraction:

Abstraction in big application framework to define default handling.

Inheritance vs. Abstraction
When functionality is to be imposed on unrelated classes then use interfaces...
When functionality is to be used on related classes then use abstraction..

Related classes: GenericList singlelinklist doublelinklist... all have the similar properties and methods...

Unrelated Classes: some function in interface which should be implemented by many component in the system.

Tricky to see which process is using which port

2009-07-19T12:32:00.000-07:00

http://www.mydigitallife.info/2008/12/03/how-to-check-and-identify-which-application-is-listening-or-opening-port-80-and-443-on-windows/

First run netstat -o -n -a
then find the process id and use this process id to find out process name and details...

To setup netbeans on Ubuntu

2009-07-17T18:03:00.000-07:00

http://www.javadesign.info/SystemsHardware/OS/Ubuntu/install-netbeans-on-ubuntu

This page describes things wonderfully...
Hope this helps...

issues with my Eclipse and Jaxb setup

2009-07-17T08:05:00.000-07:00

I was struggling a lot with my eclipse and jaxb setup.
Ultimately it turned out to be eclipse java settings on Ubuntu.

I was supposed to use sun java-6.0 but for some reason my eclipse configuration was picking up gcj-java.

In the process, i used following tricks...

Change eclipse java preferences in
/etc/eclipse/java_home

Change the by default installed JRE setting in eclipse>window>preferences...

Checked the installed vm of eclipse by looking into eclipse>help>about eclipse platform>configuration details

Changed the default JRE that needs to be included in the project while creating the project...

sudo update-alternatives --config java

and somehow it worked for me...

Saurabh

JSP notes

2009-07-13T07:43:00.000-07:00

http://www.jsptut.com/Declarations.jsp

Understand the importance of
<%= %>
To embed single line expression in the code

<% %>
To write a code block

<%! %>
Declaration to enclose your declarations

<%@ %>----> Importing some java library
for example: <%@ page language="java" import="java.sql.*" %>

Variables should not be declared as global otherwise there would be synchronization issues and performance will be hurt. Ideally all the variables should go into request or session object.

Jetty deployment

2009-07-09T14:26:00.000-07:00

For deploying on Jetty there are several ways...
1. Download the binary zipped file from source forge...
2. Extract the file and start it using general instruction of
java -jar start.jar etc/jetty.xml &
3. Create the war file.
inside war file..
4. Add a context file in contexts folder for hot deployment
For static deployment--> check the jetty.xml page

This link should help...
http://docs.codehaus.org/display/JETTY/ContextDeployer

This is the directory structure while deploying servlet on any servlet container

2009-07-09T12:46:00.000-07:00

base directory/ (this is the name of your war file)
JSP files
image files
HTML files
CSS files
any subdirectories containing additional JSP, HTML, images, and CSS
WEB-INF/
struts-config.xml
web.xml
TLD files for various tag libraries
lib/ (various .jar files for libraries you used)
classes/ (compiled .class files for your actions and action forms)
META-INF/ (this is part of the .war file)
MANIFEST.MF (the manifest file from the .war file)

Underneath the classes directory you would have compiled code for forms and actions. For example:

com/
johnmunsch/
strutstest/
actions/
LoginAction.class
SearchAction.class
forms/
LoginForm.class
SearchForm.class

This is a wonderful page which tells about the services described Tomcat file structure and installation stuff

2009-07-09T12:11:00.001-07:00

http://linux-sxs.org/internet_serving/c292.html

Wonderful.. Wonderful

Jetty server installation and running details...

2009-07-09T10:32:00.000-07:00

This is the Jetty server page...
Just download the jetty source from Jetty download page...
Read the instructions in README.txt for details...

Jetty is faster than tomcat or resin and easy to configure as well...

This page describe the things better...
http://helpme.morphexchange.com/jetty6/help/items/chapter_3_navigating_through_jetty6

Saurabh

Application server vs web app server

2009-07-08T14:48:00.000-07:00

http://www.javaworld.com/javaqa/2002-08/01-qa-0823-appvswebserver.html?page=2

This page describes the best scenarios in which application server and web app server are most suitable.

Thanks
Saurabh

Tomcat and Jetty

2009-07-08T12:42:00.000-07:00

Now days i am trying to get jetty-spring-hibernate framework running...
Here are the things that i find interesting....

Apache:
How to run apache on a different port?

1. By default Apache runs on port 80.
2. To change the port or add additional listening ports...

nano /etc/apache2/ports.conf

-- change
listen 80
-- to
listen 80
listen 8080

sudo /etc/init.d/apache2 restart
This will make apache listen on 80 and 8080. You can make it listen any other port that you want.

Tomcat:
How to change the port number on which tomcat runs?

Tomcat is a HTTP server and generally HTTP servers are related to port 80 so ideally tomcat should run on port 80 but default port for tomcat is 8080.
The reason for this is that Tomcat is good for handling Java and Jsp / Servlets code but it is not efficient for static page serving and other server side languages.

In some cases overhead of running tomcat on top of apache is poor so we can change default port of tomcat to 80.

To change the port.. We need to server.xml file
Also other way of port handling is to use kernel iptables to forward any request coming on port 80 to forward to port 8080.

Very Important page for linux and bsd related articles

2009-06-30T20:11:00.000-07:00

http://www.scottro.net/

It explains lot of things... Proper way of troubleshooting and setting up stuff on linux.

Saurabh

Hosting files on apache..

2009-06-30T09:39:00.000-07:00

Use this link... explains well
http://www.debuntu.org/2006/02/22/7-virtual-hosting-using-apache-2

1. Put files in var/www/ folder
2. Create a file in sites-available folder
3. Create a soft link in sites-enable folder
4. Change the /etc/hosts file
like 127.0.1.1

restart apache
sudo /etc/init.d/apache2 restart

What is factory pattern

2009-06-30T07:53:00.001-07:00

The Factory Pattern promotes loose coupling by eliminating the need to bind application-specific classes into the code.
The Factory method lets a class defer instantiation to subclasses" Thus, as defined by Gamma et al, "The Factory Method lets a class defer instantiation to subclasses.

Will write about it later.

leanring spring and hibernate

2009-06-24T09:01:00.000-07:00

Today i'll start learning about spring and hibernate ...
To become a full fledged expert in this field. i need to learn few prerequisite to these technologies... I'll try to implement small applications using all these technology and i hope it would extend my knowledge base.....

Hibernate: Relational data modeling, transaction processing, relational database design
Spring: Design patterns, dependency injection, application design, MVC, class and package dependency, application tiers, security and web standards

Before doing all this...
I am going to pursue this course and crack J2EE
http://www.javapassion.com/j2ee/#Introduction_of_this_course

Wonderful course...

Link for UML understanding of developers

2009-06-18T11:07:00.000-07:00

http://edn.embarcadero.com/article/31863

This link explains best the use of UML for developers perspective..

Saurabh

JavaScripting Namespacing

2009-06-04T12:08:00.000-07:00

Best way of extending a namespace in javascript
http://www.dustindiaz.com/namespace-your-javascript/

var DED = function() {
var private_var;
function private_method() {
// do stuff here
}
return {
method_1 : function() {
// do stuff here
},
method_2 : function() {
// do stuff here
}
};
}();

Finding out version of ubuntu

2009-05-30T22:51:00.001-07:00

Following commands helps in this:
lsb_release -a

cat /etc/issue

This will tell which version of ubuntu are you using.

Creating objects in javascript

2009-05-29T09:34:00.000-07:00

http://javascriptkit.com/javatutors/object.shtml

This will help in understanding the main concept of prototype chaining in Java-Script.
This also explains the need to maintaining the correct order while writing the code.

Prototype chaining helps in implementing concept of inheritance in javascript code.
This web site explains this with the help of circle and sphere example. It explains that how circle class method and properties can be used in sphere class.

function mySphere(x,y,z,r){
// DO SOME THING
}

mySphere.prototype = new circle();

Creating a custom object in JavaScript

2009-05-29T09:25:00.000-07:00

http://javascriptkit.com/javatutors/object.shtml

This include three steps:
1. creating custom object function
2. adding properties
3. adding methods

Go through the tutorial and you will understand the crux.

Ajax with jQuery

2009-05-29T08:45:00.000-07:00

http://www.dreamdealer.nl/?action=viewTutorial&id=67

Using ajax with jQuery is simple.
I see multiple methods on web. some call like
$.ajax({
type: "POST|GET",
dataType: "json|xml|....",
url: "index.php||.....",
data: param{i guess name value pairs but i am not sure},
success: function(data){
if(data.status==0){
// take action... In general programming practice,
// trueSuccess will be a function which will be called with data as argument.
// In this case, trueSuccess is an event which will be triggered ....
// This event is having some data as argument...
$("#"+listener).trigger('trueSuccess',[data]);
}else{
$("#"+listener).trigger('trueError',[data]);
}
},
error: function(){
data='An Unexpected error has occured. Please try again later.';
$("#"+listener).trigger('unexpectedError',[data]);
}
})

Ajax another way:

$.get("giveMeSomething.php", { number1: number1, number2: number2 },
function(data){
alert("Data Loaded: " + data);
});

Jquery: Random notes....

2009-05-28T07:20:00.001-07:00

$ itself is an alias for the jQuery "class", therefore $() constructs a new jQuery object.

find() function allows you to research the descendants of already selected elements.
each iterates over all the elements applied to selected class or ID and do the further processing.

$() aka jQuery(), is basically an implementation of the Factory
Pattern, in which one object is responsible for the creation of other
objects. Of course, it also follows the Prototype pattern; given that
JS is a prototypal language and that the $()/jQuery() function extends
itself into the new object that is created.

More generally, the term factory method is often used to refer to any method whose main purpose is creation of objects. Factory methods are common in toolkits and frameworks where library code needs to create objects of types which may be subclassed by applications using the framework.

$('#faq').find('dd').hide().end().find('dt').click(function()
Here end will cancel the first find and second find will start from scratch.

jQuery.fn is a shortcut for jQuery.prototype
function($) {

} .. here $ refers to jQuery object...

http://simonwillison.net/2007/Aug/15/jquery/

Difference between
$().bind('click',fn) and $().click(fn)
Two difference:
bind can attach multiple function event to function name in a single statement.
something like this: $("(DIV ID)").bind("mouseout focus", function(){

});

Bind can also attach the custom events with any UI element.

2009-05-22T14:34:00.000-07:00

http://www.24hourapps.com/2009/03/object-oriented-event-handling-in.html

Something relevant to my work.....

CSS selector tutorial

2009-05-22T09:20:00.000-07:00

This tutorial will help in designing my web page in a better way...
http://css.maxdesign.com.au/selectutorial/tutorial_step22.htm

Use these styling rules....

Mac OS: working with textedit

2009-05-20T14:27:00.000-07:00

I was stuck for a minute with text/edit.
Got confused that how can i save a file in html extension and get it properly displayed on browser:

For this i did this:
http://www.askdavetaylor.com/how_do_i_save_html_files_from_textedit.html

I changed the format from rich text format to plain text format and it worked for me.

Internship Day 1: JQUERY resources

2009-05-20T14:06:00.000-07:00

Event Driven Programming:

http://www.mostlygeek.com/tech/event-driven-programming-with-jquery/

Basic Jquery tutorial:

http://ldeveloper.blogspot.com/2008/10/intro-to-jquery-basic-tutorial.html

Excellent JQuery Examples:

http://www.noupe.com/tutorial/51-best-of-jquery-tutorials-and-examples.html

Something for designers:

http://www.webdesignerwall.com/tutorials/jquery-tutorials-for-designers/

15 minutes Jquery expert:

http://www.webdevelopment2.com/give-15-minutes-jquery-expert/

How JQUERY works:

http://docs.jquery.com/How_jQuery_Works

Few links for tomorrow reading:

Advertiser Portal Documents ( check attached documents & ppt )
http://tortoise.hq.reloadnyc.com/groups/piggypost/wiki/6d2ca/2.1.9_Detail_Design_of_Advertiser_User_Interface.html
For the mockup -> refer to the link (Reddhima's wiki ( UI Mockup ))
P3 Portal ( Admin portal )
http://tortoise.hq.reloadnyc.com/groups/piggypost/wiki/0ce13/Admin_Portal.html
Look for p3 portal link
UI Common
http://tortoise.hq.reloadnyc.com/groups/piggypost/wiki/253aa/User_Interface_Common.html