Information Technology Tips

Value of reducing code Reducing amount of code is one of the MOST REQUIRED & IMPORTANT skill in real software development workplace, especially in team based software development. Most of the case, reducing code is much more valuable than writing code! Why doesn't any computer science teach this MOST important skill! Let me point out benefits of reducing code: The less code makes programmer be the easy to understand project! The amount of code they should read is lesser! Fledgling developer easy to understand! You don't have to write much test code! Complexity should tend to be lower! Code duplication tends to be less! Prevent regression! You can only care about code which really lively works! Put it all together, These benefits finally leads "Improve code maintainability" and "Reduce maintenance cost" . I mention just in case - reducing code doesn't mean you should merge a few "for loop" lines into single line. My pri...

Identify Country From IP Address Many people sometimes would like to identify country from IP address when you check access log or something. Most of the people google with keywords like "ip address country" or "whois ip" or something, and then use the internet service which they find. In this post, I will show you program for identifying country from IP address. I wrote the program in Java, but if you an average developer you can easily translate into the program language you prefer. Using File Provided by RIR IP address is allocated, registered and managed by regional internet registry ( RIR ). There are five organization based on covering region: African Network Information Centre (AfriNIC): Africa American Registry for Internet Numbers (ARIN): the United States, Canada, several parts of the Caribbean region, and Antarctica. Asia-Pacific Network Information Centre (APNIC): Asia, Australia, New Zealand, and neighboring countries Latin America and ...

IPv6 Address to Long I have written code for converting coloned IPv6 IP address to BigInteger value in Java. I have already written similar code for IPv4 IP address (see this post ). The function is useful when you compare IP addresses based on numeric magnitude relationship. Java Code public static BigInteger colonIpV6_to_BigInteger(String colonedIP) { String[] addrArray = colonedIP.split(":", -1); BigInteger num = BigInteger.ZERO; BigInteger block = BigInteger.valueOf(65536); for (int i = 0; i < addrArray.length; i++) { if(!addrArray[i].equals("")) { int power = 8-i; BigInteger value = BigInteger.valueOf(Long.parseLong(addrArray[i], 16) % 65536L); value = value.multiply(block.pow(power)); num = num.add(value); } } return num; } Here is an example. // following code output "22170076769632982771575277020213308075606016"...

IPv4 Address to Long I have written code for converting dotted IPv4 IP address to BigInteger value in Java. This code is inspired by PHP's ip2long function. The function is useful when you compare IP addresses based on numeric magnitude relationship. Java Code public static BigInteger dotIPv4_to_BigInteger(String dottedIP) { String[] addrArray = dottedIP.split("\\."); BigInteger num = BigInteger.ZERO; BigInteger block = BigInteger.valueOf(256); for (int i = 0; i < addrArray.length; i++) { int power = 3-i; BigInteger value = BigInteger.valueOf(Integer.parseInt(addrArray[i]) % 256); value = value.multiply(block.pow(power)); num = num.add(value); } return num; } Here is an example. // following code output "2071690107" System.out.println(dotIPv4_to_BigInteger("123.123.123.123"));

Introduction In this post, I'm going to write about "Why & How to measure your code of software project. And improve it." I am going to mainly write about this topic from the static code analysis point. Why Measure? There are number of reasons to measure your code. For me especially following reasons (or intentions). Daily Health Check Keep code base clean See impact on entire code base by your code change Detect problems as soon as possible Feel improvement! Let every team members show what happens Monitor test result status Follow coding standard Especially in team based software development, a lot of people change code for different task. And each developer is hard to know what each developer change the code for what purpose. If the source code measurement is public for everyone, it helps everyone to know affect of entire project which the other developers make. What to Measure? There are a lot of measurement is proposed but from static...

Symfony 1.4 Action plus View Rendering PHPUnit Test I wrote test case for executing action and rendering view test. However testing action plus final rendering result is quite not easy because you need to understand how Symfony 1.4 framework handles web request and rendering model to view internally. I have investigated in the framework a bit and found a solution. Please see the test case example in the next section. Code <?php $basePath = dirname(__FILE__).'/../../../../apps/your_app_name/modules/'; $modulePaths = glob($basePath.'*', GLOB_ONLYDIR); foreach($modulePaths as $modulePath) { require_once $modulePath.'/actions/actions.class.php'; } class ActionsTest extends PHPUnit_Framework_TestCase { public function testActions() { // create stub web request $request = $this->createStubfWebRequest(); // action you would like to test. // you should pass module and action name refelctively $actions = new TargetActions($this...

Motivation: Visualize 2 Dimensional Data with Lightweight Way I wrote small java program for calculating Jaccard Similarity among source code in this post . And map into them 2 dimensional map using Multi Dimensional Scaling technique. I have used MDSJ – Multidimensional Scaling for Java . (By the way the library is quite simple and meet my requirement perfectly!! Excellent!!)> Next step is how to visualize the bunch of 2 dimensional (x,y) coordinate data so that human can easily understand. Of course, I am good at Java, I can write some code for visualize data in Java using Swing or Java FX etc. But it's not lightweight way. So, I decided to use HTML5 Canvas + Javascript. Viewer: Html5 Canvas + Javascript The features of the Data Viewer are: Visualize CSV data Expected 3 columns without header row: name...