GT's Blog

grails detecting environment groovy & gsp code

2012-08-19T03:31:00.001+01:00

Grails/Groovy working code snippet to detect the current environment (development, test, production, or your custom). Custom environment are defined in config.groovy file.

Detecting Environment in GSP code :

Following checks if current environment is other than production.

    <g:if test="${env != "production"}">
        //your logic 

    </g:if>

Detecting environment in Groovy Code ( in Controller, Service, etc..), using switch-case comparison

        switch(Environment.current.getName()){
            case "development":
                //do your stuff 1
                break;
            case "test":
                //do your stuff 2
                break;
            case "production":
                //do your stuff 3
                break;
            case "my_environment":  // for custom environment : my_environment
                //todo:
                break;
        }

Simple comparison in groovy

if(Environment.current.getName()=="development") {
    //do your stuff
}

Grails - auto login in spring security

2012-08-14T18:54:00.001+01:00

Consider a typical web application where you have multiple user roles (like SUPER_ADMIN, OPERATOR, VISITOR etc ) and you need to do login and switch between them frequently. It certainly consumes a lot of time if you do this manually. One simple solution would be to use the browser's password remember feature. But this would not be useful if you need to switch between different role.

Here, I am going to do show how we can setup this mechanism in Grails applications which uses Spring Security plugin.

If you are using Spring Security plugin then, by default you will have following names for html textbox for username and password : j_username and j_password. and you have login request url as http://localhost:8080/YOUR_APP/j_spring_security_check .

The required login script :

It does the login form submission using hidden fields. You need to change YOUR_APP according to your app.

        <script>
        function doLogin(username, password){
                var path='http://localhost:8080/YOUR_APP/j_spring_security_check';
                var params={'j_username':username,'j_password':password};
                var form=document.createElement("form");
                form.setAttribute("method","POST");
                form.setAttribute("action",path);
                //set params into hidden field and submit 
                for(var key in params){
                    var hiddenField=document.createElement("input");
                    hiddenField.setAttribute("type","hidden");
                    hiddenField.setAttribute("name",key);
                    hiddenField.setAttribute("value",params[key]);
                    form.appendChild(hiddenField);
                }document.body.appendChild(form);
                form.submit();
            };
        </script>

Now use this script as :

    <button onClick="doLogin('user1', 'password')">Login-User1</button>
    <button onClick="doLogin('admin1', '123456')">Login-Admin1</button>
    ...for any required roles

Detecting the production environment:

As this feature shouldn't be available in production environment we should do the following check for this.

<g:if test="${env != "production"}">
//login code
</g:if>

The full code

( we can post this in layout/main.gsp so that it appears in all pages) :

<body>
    <g:if test="${env != "production"}">
        <script>
        function doLogin(username, password){
                var path='http://localhost:8080/YOUR_APP/j_spring_security_check';
                var params={'j_username':username,'j_password':password};
                var form=document.createElement("form");
                form.setAttribute("method","POST");
                form.setAttribute("action",path);
                //set params into hidden field and submit 
                for(var key in params){
                    var hiddenField=document.createElement("input");
                    hiddenField.setAttribute("type","hidden");
                    hiddenField.setAttribute("name",key);
                    hiddenField.setAttribute("value",params[key]);
                    form.appendChild(hiddenField);
                }document.body.appendChild(form);
                form.submit();
            };
        </script>
    <button onClick="doLogin('operator1', '123456')">Login-Operator1</button>
    <button onClick="doLogin('operator2', '123456')">Login-Operator1</button>
    </g:if>
    ...
    ...
    ...rest of the layout code
    </body>

Source : Speed up your Grails / Spring Security Development with an Auto Login Bookmarklet

Groovy Grails - Dynamic Method n Variable name and invoking them

2012-08-01T17:05:00.000+01:00

Groovy allows to use dynamic method name and variable name and invoke/use them.

Dynamic Variable Names

Groovy allows to use variable name dynamically. To test this lets introduce a variable "dogname" to Dog class

class Dog {

def dogname

...

}

//Testing dynamic variable name

def aDog= new Dog()

aDog.name="Hachi"

def prop="dogname"

println aDog."$prop" // prints Hachi

Dynamic Method Invocation :

You can invoke a method even if you don't know the method name until it is invoked: In the example below, we are executing the method in the Dog class without knowing the method name in advance. We are simply passing a String to the method doAction as doAction( rex, "bark" ) and inside doAction method, we are calling the actual function whose name is fromed based on the second parameter to the doAction method - action. -> animal."$action"()

//dog class

class Dog {
  def bark() { println "woof!" }
  def sit() { println "(sitting)" }
  def jump() { println "boing!" }
}

def doAction( animal, action ) {

    //creating the method name out of the action parameter 
  animal."$action"()                  //action name is passed at invocation
}

def rex = new Dog()

doAction( rex, "bark" )               //prints 'woof!'
doAction( rex, "jump" )               //prints 'boing!'

Reference: http://groovy.codehaus.org/Dynamic+Groovy

git- saving username password - credential.helper cache - how to

2012-07-16T12:33:00.003+01:00

Isn't is interesting if there is an option in GIT to save your credentials for short time so that you don't enter your username/password repeatedly each time when you do pull/push? Yes! there is an option introduced in GIT since 1.7.9 (released on January 2012). This method is more secure than permanently saving your username/password in .git file of your git clone directory.

So, run the following command at the GIT console (git bash) :

git config --global credential.helper cache

This caches the credentials for 15 minutes ( 900 seconds) by default. If you want a longer timeout period (say3600 seconds), you can do the following :

git config --global credential.helper 'cache --timeout=3600'

Grails - beginners video tutorial

2012-06-27T11:12:00.001+01:00

From the Grails site: "Grails aims to bring the 'coding by convention' paradigm to Groovy. It's an open-source web application framework that leverages the Groovy language and complements Java Web development. You can use Grails as a standalone development environment that hides all configuration details or integrate your Java business logic. Grails aims to make development as simple as possible and hence should appeal to a wide range of developers not just those from the Java community."

Here is list of some useful video tutorials on Grails framework.

From SpringSourceDev :

Getting Started with Grails - Part 1 - http://www.youtube.com/watch?v=PXHxo43hn34

process of creating a simple domain model and generating a basic CRUD user interface for the model through Grails' scaffolding.

Getting Started with Grails - Part 2 - http://www.youtube.com/watch?v=qNFksvLxZNU

start building a custom user interface for your web applications using controller actions, GSP views, and CSS stylesheets.

Getting Started with Grails - Part 3 - http://www.youtube.com/watch?v=oL4yVtNU31E

learn about custom GSP tags and how they can promote reuse between your views.

From Grails Example .net

Creating a Model Part 1 - http://www.youtube.com/watch?v=hGjCYfLZF_8
Creating a Model Part 2 - http://www.youtube.com/watch?v=y2ul-LIvniw
Creating a View - http://www.youtube.com/watch?v=tzqxCuWq6k4
Creating a Controller - http://www.youtube.com/watch?v=mU0vgIPFcQo
Dynamic Scaffolding - http://www.youtube.com/watch?v=3hVXw2DoI_8
Constraints and Static Scaffolding - http://www.youtube.com/watch?v=N-Ysr3P9-to
Basic Grails Security - http://www.youtube.com/watch?v=xoDG6Anbx84

... more coming soon

grails- add jar to lib folder - not working - solution

2012-06-24T09:09:00.003+01:00

In grails application you can add jar dependencies by just pasting the .jar file to lib folder. If your code doesn't find the jar dependency at runtime then you can do following :

Run the following grail command (s):

clean
compile --refresh-dependencies

In eclipse you can open the Grails Command Prompt by :
Right Click on project -> Grail Tools -> Open Grails Command Prompt

Hope this helps.

nepali english date conversion logic - working java code

2012-06-18T06:59:00.002+01:00

I just found someone has blogged about Nepali-English date conversion in this post:

http://forjavaprogrammers.blogspot.com/2012/06/how-to-convert-english-date-to-nepali.html

He has explained the algorithm in detail about how to convert English dates into Nepali dates with java code.

java spring - read properties file variable from xml -PropertyPlaceholderConfigurer

2012-06-10T07:24:00.004+01:00

Java springframework xml configuration file - how to read properties file variables from spring xml :
We have to use PropertyPlaceholderConfigurer bean for this.

1).properties file location -

src/main/resource @ maven managed project
OR at classpath

2)The xml code to initialize/read properties file,

I have a sample config.properties file at either of above location.


    <bean
        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations" value="classpath:config.properties" />
    </bean>

3)config.properties file content -

server.url=http://localhost:8080/testapp/

4)Using this server.url at xml file :

We have to use - ${server.url}

eg :

<property name="serviceUrl" value="${server.url}testService" />

-OR

<sometag name="someName"> ${server.url} </sometag>

hibernate annotation inheritance mappedsuperclass - common columns in super class

2012-06-10T07:09:00.004+01:00

When you are using annotations for hibernate object relational mapping, there might be the case that we need to abstract out some common columns that goes into all table definitions. These columns might be ID, DFlag, LastModifiedDate etc..
In such case we can take advantage of @MappedSuperclass annotation to achieve inheritance in hibernate annotation.

Example :

Super class BaseTable that contains common column definitions:

@MappedSuperclass
public abstract class BaseTable {
    @Id
    @GeneratedValue
    @Column(name = "id")
    private int id;

    @Column(name = "dflag")
    private int dFlag;

    @Column(name = "lastmodifieddate")
    private Date lastModifiedDate;
    
    //other required columns
....
}

Extending it to use in other tables :


@Entity
@Table(name = "LoginUser")
public class LoginUser extends BaseTable  implements Serializable{

    private static final long serialVersionUID = -1920053571118011085L;

    @Column(name = "username")
    private String username;

    @Column(name = "password")
    private String password;

    @Column(name = "invalidCount")
    private int invalidCount;
    
    //other required tables
   ...
}

It works !

mysql hibernate unicode support - character set, collate

2012-06-09T06:41:00.002+01:00

I just did following configurations to achieve Unicode support in my Java+Hibernate+MySQL project.

Configuring MySQL to support Unicode - set Character Set and Collate as :

CREATE TABLE YOUR_DB_NAME
 CHARACTER SET "UTF8"
 COLLATE "utf8_general_ci";

NOTE : You Need to do "ALTER TABLE" instead of "CREATE TABLE", 
      if you are going to modify existing DB.

Hibernate JDBC connection string :

jdbc.url=jdbc:mysql://localhost:3306/YOUR_DB_NAME?useUnicode=true&characterEncoding=UTF-8

Hibernate Configuration:

<hibernate-configuration>
<session-factory>
    ...
    <property name="hibernate.connection.charSet">UTF-8</property>
    <property name="hibernate.connection.characterEncoding">UTF-8</property>
    <property name="hibernate.connection.useUnicode">true</property>
    ...
</session-factory>
</hibernate-configuration>

Java code to find public IP address (servlet and client side code)

2012-06-06T11:14:00.000+01:00

Java code to find public IP address :

URL url= new URL("http://gt-tests.appspot.com/ip");
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String ip = in.readLine();
System.out.println("IP : "+ip);

I created a simple servlet app on google app engine and posted at http://gt-tests.appspot.com/ip .

The servlet code returns the public address of client, it looks like :

public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
  PrintWriter out = resp.getWriter();
  // Get client's IP address
  String addr = req.getRemoteAddr();
  out.println(addr);
  ...

Java Script code that disables right click and prevents selecting the text on web page.

2012-05-31T17:32:00.001+01:00

Java Script code that disables right click and selecting the text on web page.

Put the following code in your <body>........</body> tag.

<script>
function disableselect(e){return false;}
function reEnable(){return true;}
document.onselectstart=new Function (){return false;}
if (window.sidebar){
    document.onmousedown=disableselect;
    document.onclick=reEnable;
}
</script>

<script>
document.oncontextmenu = function(){return false;}
if(document.layers) {
    window.captureEvents(Event.MOUSEDOWN);
    window.onmousedown = function(e){
        if(e.target==document)
        return false;
    }
}else {
    document.onmousedown = function(){return false;}
}

For Blogger template,

Search for </body> in the template code
paste the above script just before </body> tage.

Enjoy !

You are now safe from website article thief.

facebook security bug - change password of a active user - without knowing original password

2012-05-29T19:33:00.002+01:00

change password of a active user -without knowing original password - security bug - Facebook allows to change password in active login without entering current password

As of May 2012, Facebook has over 900 million active users. Security and privacy should be the number one concern of Facebook Inc. But I just found one BUG in Facebook security system.

This might (not) be a security bug in Facebook. And probably be fixed by Facebook when you tried to do the same, because I am going to report this to Facebook.

All the steps below that I am going to share - deals with changing someone else’s password without entering their previous/current password. I have never seen or write code for “login preference change” that allows to change password without entering previous password or other information. I was shocked to know that Facebook allows it. I was just playing with Security option in Facebook’s Account setting https://www.facebook.com/settings. And found that.

Steps that I followed :

Go to Facebook’s Account setting https://www.facebook.com/settings and choose Security. And then choose “Deactivate your account”.

Choose “My account was hacked” and click “here”.

why there is option "My account was hacked" ?

Continue --> Continue.

Here is the odd thing. No input text field for Old password.

Facebook allows to change password in active login without entering current password

And then you will see following screens. Continue --> Continue.

Some thoughts :

If a user’s account was really hacked then they wouldn’t be able to login and see this screen. This screen/option can be accessed by a genuine user, then isn’t this option “My account was hacked” odd? What is the actual purpose of this option?

Consider a situation like this – you logged in into FB account from a PC and forget to logout. Then anyone can change their password and misuse.
This wouldn't be a big problem because Once the genuine user knows that someone else had changed their password, they won't lose their account, they can still reset their password. I just don’t know why they put “My account was hacked” option in “Deactivate your account”. This option is completely useless.

eclipse proguard maven project configuration - java obfuscate

2012-05-20T06:57:00.000+01:00

I am going to describe how can can configure proguard and maven to obfuscate a java project. If you need help on how to configure maven project in eclipse see my earlier post.

A)Project configs

    <!-- Project configs -->
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.gt</groupId>
    <artifactId>maven-proguard-test</artifactId>
    <packaging>jar</packaging>
    <version>-ver.01</version>
    <name>maven-proguard-test-application</name>

    <properties>
        <project.build.mainClass>com.gt.App</project.build.mainClass>
    </properties>

B) Proguard Configuration in pom.xml :

            <!-- Proguard configs -->
            <plugin>
                <groupId>com.pyx4me</groupId>
                <artifactId>proguard-maven-plugin</artifactId>
                <version>2.0.4</version>

                <!-- run proguard at package phase -->
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>proguard</goal>
                        </goals>
                    </execution>
                </executions>

                <configuration>
                    <obfuscate>true</obfuscate>
                    <archive>
                        <manifest>
                            <mainClass>${project.build.mainClass}</mainClass>
                        </manifest>
                    </archive>
                    <options>
                        <option>-allowaccessmodification</option>
                        <option>-dontshrink</option>
                        <option>-keepattributes *Annotation*</option>
                        <option>-keep public class ${project.build.mainClass} { *; }</option>
                        <!-- <option>-keep public class [com.qualified_name]</option> -->

                        <!-- if you want to keep enum classes, this is generally expected -->
                        <option>-keep public enum * { *;}</option>
                    </options>
                    <outjar>${project.build.finalName}.jar</outjar>
                    <libs>
                        <lib>${java.home}/lib/rt.jar</lib>
                        <lib>${java.home}/lib/jsse.jar</lib>
                        <lib>${java.home}/lib/jce.jar</lib>
                    </libs>
                </configuration>
                <dependencies>
                    <dependency>
                        <groupId>net.sf.proguard</groupId>
                        <artifactId>proguard</artifactId>
                        <version>4.4</version>
                        <scope>runtime</scope>
                    </dependency>
                </dependencies>
            </plugin>

C)Maven jar plugin to make .jar file

            <!-- making jar file -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>${project.build.mainClass}</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>

D)Maven dependency plugin - copy jar dependencies

            <!-- maven dependency plugin to copy all dependency jar to a folder, here 
                copying to target/lib -->
            <plugin>
                <artifactId>maven-dependency-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-dependencies</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>target/lib</outputDirectory>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

E)run.bat file to run the jar file ( it loads the jar files in classpath) You need to copy run.jar file to target folder. com.gt.App is my main class.

@echo off
Start "" /B javaw -Xmx256M -cp "maven-proguard-test-0.0.1-SNAPSHOT.jar;lib/*" com.gt.App

F)Build command : mvn clean compile package

Project folder structure :

The complete Source CODE at Google Code SVN Repo :
http://code.google.com/p/maven-proguard-eclipse-java-project-configuration-working/

Speech Recognition Java Code - HMM VQ MFCC ( Hidden markov model, Vector Quantization and Mel Filter Cepstral Coefficient)

2012-05-20T05:05:00.000+01:00

Hi everyone, I have shared speech recognition code in google code : http://code.google.com/p/speech-recognition-java-hidden-markov-model-vq-mfcc/
You can find complete source code for speech recognition using HMM, VQ, MFCC ( Hidden markov model, Vector Quantization and Mel Filter Cepstral Coefficient). Feel free to use and modify this code.

The project report that accompanies this code is here.http://ganeshtiwaridotcomdotnp.blogspot.com/2011/06/final-report-text-prompted-remote.html

Introduction to the project : http://ganeshtiwaridotcomdotnp.blogspot.com/2010/12/text-prompted-remote-speaker.html

colored object tracking in java- javacv code

2012-04-21T08:18:00.000+01:00

Code for this demo video - Color Based Image Segmentation to Track Path of Moving Object

Working Source Code :

import static com.googlecode.javacv.cpp.opencv_core.IPL_DEPTH_8U;
import static com.googlecode.javacv.cpp.opencv_core.cvCreateImage;
import static com.googlecode.javacv.cpp.opencv_core.cvFlip;
import static com.googlecode.javacv.cpp.opencv_core.cvGetSize;
import static com.googlecode.javacv.cpp.opencv_core.cvInRangeS;
import static com.googlecode.javacv.cpp.opencv_core.cvScalar;
import static com.googlecode.javacv.cpp.opencv_imgproc.CV_BGR2GRAY;
import static com.googlecode.javacv.cpp.opencv_imgproc.CV_MEDIAN;
import static com.googlecode.javacv.cpp.opencv_imgproc.cvCvtColor;
import static com.googlecode.javacv.cpp.opencv_imgproc.cvEqualizeHist;
import static com.googlecode.javacv.cpp.opencv_imgproc.cvGetCentralMoment;
import static com.googlecode.javacv.cpp.opencv_imgproc.cvGetSpatialMoment;
import static com.googlecode.javacv.cpp.opencv_imgproc.cvMoments;
import static com.googlecode.javacv.cpp.opencv_imgproc.cvSmooth;
import static com.googlecode.javacv.cpp.opencv_highgui.*;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;

import javax.swing.JPanel;

import com.googlecode.javacv.CanvasFrame;
import com.googlecode.javacv.FrameGrabber;
import com.googlecode.javacv.VideoInputFrameGrabber;
import com.googlecode.javacv.cpp.opencv_core.CvScalar;
import com.googlecode.javacv.cpp.opencv_core.IplImage;
import com.googlecode.javacv.cpp.opencv_imgproc.CvMoments;

public class ColoredObjectTrack implements Runnable {
    final int INTERVAL = 1000;// 1sec
    final int CAMERA_NUM = 0; // Default camera for this time

    /**
     * Correct the color range- it depends upon the object, camera quality,
     * environment.
     */
    static CvScalar rgba_min = cvScalar(0, 0, 130, 0);// RED wide dabur birko
    static CvScalar rgba_max = cvScalar(80, 80, 255, 0);

    IplImage image;
    CanvasFrame canvas = new CanvasFrame("Web Cam Live");
    CanvasFrame path = new CanvasFrame("Detection");
    int ii = 0;
    JPanel jp = new JPanel();

    public ColoredObjectTrack() {
        canvas.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
        path.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
        path.setContentPane(jp);
    }

    @Override
    public void run() {
        FrameGrabber grabber = new VideoInputFrameGrabber(CAMERA_NUM);
        try {
            grabber.start();
            IplImage img;
            int posX = 0;
            int posY = 0;
            while (true) {
                img = grabber.grab();
                if (img != null) {
                    // show image on window
                    cvFlip(img, img, 1);// l-r = 90_degrees_steps_anti_clockwise
                    canvas.showImage(img);
                    IplImage detectThrs = getThresholdImage(img);

                    CvMoments moments = new CvMoments();
                    cvMoments(detectThrs, moments, 1);
                    double mom10 = cvGetSpatialMoment(moments, 1, 0);
                    double mom01 = cvGetSpatialMoment(moments, 0, 1);
                    double area = cvGetCentralMoment(moments, 0, 0);
                    posX = (int) (mom10 / area);
                    posY = (int) (mom01 / area);
                    // only if its a valid position
                    if (posX > 0 && posY > 0) {
                        paint(img, posX, posY);
                    }
                }
                // Thread.sleep(INTERVAL);
            }
        } catch (Exception e) {
        }
    }

    private void paint(IplImage img, int posX, int posY) {
        Graphics g = jp.getGraphics();
        path.setSize(img.width(), img.height());
        // g.clearRect(0, 0, img.width(), img.height());
        g.setColor(Color.RED);
        // g.fillOval(posX, posY, 20, 20);
        g.drawOval(posX, posY, 20, 20);
        System.out.println(posX + " , " + posY);

    }

    private IplImage getThresholdImage(IplImage orgImg) {
        IplImage imgThreshold = cvCreateImage(cvGetSize(orgImg), 8, 1);
        //
        cvInRangeS(orgImg, rgba_min, rgba_max, imgThreshold);// red

        cvSmooth(imgThreshold, imgThreshold, CV_MEDIAN, 15);
        cvSaveImage(++ii + "dsmthreshold.jpg", imgThreshold);
        return imgThreshold;
    }

    public static void main(String[] args) {
        ColoredObjectTrack cot = new ColoredObjectTrack();
        Thread th = new Thread(cot);
        th.start();
    }

    public IplImage Equalize(BufferedImage bufferedimg) {
        IplImage iploriginal = IplImage.createFrom(bufferedimg);
        IplImage srcimg = IplImage.create(iploriginal.width(), iploriginal.height(), IPL_DEPTH_8U, 1);
        IplImage destimg = IplImage.create(iploriginal.width(), iploriginal.height(), IPL_DEPTH_8U, 1);
        cvCvtColor(iploriginal, srcimg, CV_BGR2GRAY);
        cvEqualizeHist(srcimg, destimg);
        return destimg;
    }
}

Mouse Gesture Recognition Using Hidden Markov Model - Java Source Code

2012-04-20T18:52:00.004+01:00

Hi everyone, I have uploaded the codes for my project - "Mouse Gesture Recognition with Hidden Markov Model - Java".

You can find it @ google code : https://code.google.com/p/mouse-gesture-recognition-java-hidden-markov-model/.

This svn repository @ google code contains eclipse source code (VQ and HMM codes from OCVolume Project.) , trained hmm models and codebook, captured data for few gestures.

Similar codes for Speech Recognition System using HMM/VQ + MFCC will be uploaded SOON.

DEMO VIDEO: http://www.youtube.com/watch?v=0CNJ2fCj4xQ

maven install jar to repository locally

2012-04-19T04:04:00.004+01:00

Run the following command to install the "MyJar-x.x.x.jar" into Local maven repository. The underlined values vary in your case.

mvn install:install-file -Dfile=PathOFJar_MyJar-x.x.x.jar -DgroupId=com.mycompany -DartifactId=myJar -Dversion=x.x.x -Dpackaging=jar

After installing, Add the dependency into Pom.xml :

        <dependency>
            <groupId>com.mycompany</groupId>
            <artifactId>myJar</artifactId>
            <version>x.x.x</version>
        </dependency>

Java grey image from RGB image convert full source code

2012-04-14T16:18:00.001+01:00

The java code below is for making grey image from a image

public static void main(String[] args) {
        BufferedImage org = getImage("test.jpg");
        BufferedImage greyImage = getGrayScaleAvg(org);
        new ImageFrame(org, "Original");
        new ImageFrame(greyImage, "After GrayScale");
    }

Full working source code : averages the pixels to obtain grey image

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class tempgrey {
    public static void main(String[] args) {
        BufferedImage org = getImage("test.jpg");//valid input image
        BufferedImage greyImage = getGrayScaleAvg(org);
        new ImageFrame(org, "Original");
        new ImageFrame(greyImage, "After GrayScale");
    }

    public static BufferedImage getImage(String imageName) {
        try {
            File input = new File(imageName);
            BufferedImage image = ImageIO.read(input);
            return image;
        } catch (IOException ie) {
            System.out.println("Error:" + ie.getMessage());
        }
        return null;
    }

    public static BufferedImage getGrayScaleAvg(BufferedImage img) {
        int w1 = img.getWidth();
        int h1 = img.getHeight();
        // int value[][] = new int[w1][h1];
        BufferedImage gray = new BufferedImage(w1, h1, 1);// new image
        int value, alpha, r, g, b;
        for (int i = 0; i < w1; i++) {
            for (int j = 0; j < h1; j++) {
                value = img.getRGB(i, j); // read and store pixel value
                alpha = get_alpha(value);
                r = get_red(value);
                g = get_green(value);
                b = get_blue(value);

                value = (r + g + b) / 3; // grey by averaging the pixels
                r = g = b = value;
                value = create_rgb(alpha, r, g, b);
                gray.setRGB(i, j, value);
            }
        }
        return gray;
    }

    public static int create_rgb(int alpha, int r, int g, int b) {
        int rgb = (alpha << 24) + (r << 16) + (g << 8) + b;
        return rgb;
    }

    public static int get_alpha(int rgb) {
        return (rgb >> 24) & 0xFF;
        // return rgb & 0xFF000000;
    }

    public static int get_red(int rgb) {
        return (rgb >> 16) & 0xFF;
        // return rgb & 0x00FF0000;
    }

    public static int get_green(int rgb) {
        return (rgb >> 8) & 0xFF;
    }

    public static int get_blue(int rgb) {
        return rgb & 0xFF;
    }
}

java servlet/jsp download string into text file - spring controller method

2012-04-11T12:23:00.002+01:00

Working example for downloading a text file out of a String . Code segment in Spring MVC controller .


 @RequestMapping(value = "/download", method = RequestMethod.GET)
 public @ResponseBody
 void downloadFile(HttpServletResponse resp) {
  String downloadFileName= "download.txt";
  String downloadStringContent="Download text \n This is working.";
  try {
   OutputStream out = resp.getOutputStream();
   resp.setContentType("text/plain; charset=utf-8");
   resp.addHeader("Content-Disposition","attachment; filename=\"" + downloadFileName + "\"");
   out.write(downloadStringContent.getBytes(Charset.forName("UTF-8")));
   out.flush();
   out.close();

  } catch (IOException e) {
  }
 }

Job Interview Question Answer Frequently Asked - programmer

2012-02-05T04:10:00.000Z

Some Common and most asked job interview question ( for programmer) and their answers. In Nepali Context.

These questions are the most common questions ( in my job haunt experience) that will be asked to you in your interview.

1. Tell me about yourself:
After finishing computer engineering from XXX campus last year, i worked as java developer. I have good command of Java related technologies. I also have interest in XXX. I find myself as a hard worker and quick learner. And I think i am a good candidate for the position.

2. Last Jobs:
My first job was at XXX as N months contract. Our responsibilites were bug fixing and upgrading an existing XXX system. It was a web app. I mainly worked in feature enhancement like : XXX and some business modules like report generations.
After finishing the contract, i joined XXX as java developer. There too i worked in a business application for healthcare related dataprocessing/reporting application . I mainly write code for XXX , XXX etc.

3. Why did you leave your last job?
In fact it was a good time working for XXX but i couldnot find any learning opportunity there, I always wanted a challanging job where i can contribute myself and learn something. I worked there for N months and decided to quit the job.

What did you did in this free time :
After i quit the job - besides job haunting, i did a freelancing project- it was XXX,..,
Meanwhile, i learned android framework and teach java in an institute for about 1 month.

6. How do you know about this position?
I knew about this org from the job vacancy notice posted in XXX.com.

7. What do you know about this organization?
XXX is a 10 year old software company located in XXX. it mainly works on XXX. Its major clients are XXX. Major products are XXX.

11. What kind of salary do you need?
As i have few experience and skills, and this might be somehow different job from my previous ... ummm...well ... NN000 NRS/Mo will be fine.

13. How long would you expect to work for us if hired?
I would work as long as you and i both enjoy working me in XXX. I am certain that, I will enjoy the job at XXX##??

25. What are you looking for in a job?
Where i can contribute more and learn new things in the process . not only technically but also the detail of business domain on which i am working at.

50. Do you have any questions for me?
Well ... yes i think i have one.

>> what will be the next possible step in selection process.
>> what type of responsibilities
>>

Correct way of connecting ADSL splitter and router

2012-01-10T10:12:00.000Z

REMEMBER : If you need extensions, connect it after splitter only.

Right way of connecting adsl splitter and router in telephone line

Wrong way of connecting adsl router, splitter in telephone line

correct adsl connection diagram, router, computer, splitter, telephone line

NTC ADSL Configuration Working Way

2012-01-10T09:57:00.000Z

To configure ADSL setting in a ADSL Router, you need to enter the following informations .

The (generic) easy steps :

1) Open 192.168.1.1 (in most routers) in router,
use admin for username and admin for password (If it doesnot work, refer to the manual of router, the login information can be found on back of router)

2) Search for the ADSL settings page in the router config -
For Routing Mode (where router automatically dials the connection), You need to provide/choose the following minimum settings there

>Choose PPPOE LLC for Connection type or encapsulation
>Enter correct username and password given by NTC
>Choose authentication AUTO
>provide 8 for VPI, and 81 for VCI

3) Save the connection settings and restart the router.
4) Make sure all the LEDS including internet is ON.

tips - learn programming faster and effectively

2012-01-08T06:18:00.000Z

How to learn programming effectively- tips for developing programming skills

Tip1 : Have detail knowledge of following and practice them in your favorite programming language

Design Patterns / Anti Patterns
UML
OOAD

Tip2 : Participate in Online/offline coding contests : develop your programming logics

Tip3 : Create your own Blog - blogger.com or wordpress.com

Write about new things you learn today
publish your code snippets, ideas, participate in discussion with your blog reader

Tip4 : Read Tech-articles regularly

Tip5 : Participate on QA, Discussion forum

Create your account on stackoverflow.com today. It is the best site for QA
read the most voted questions in stackoverflow

Career suggestion for nepali computer engineers programmers student

2012-01-08T06:17:00.000Z

Career Suggestions/guidelines to Computer Engineering BE, BCA, BTech, BSc-CS, BIT students

Self Study
Internet is your library - Search, search and search more
Try to understand the concept of programming not language
Algorithms and Data Structures are everything
Do you know Design Patterns ?
Projects are portfolio for your first job interview
Wikipedia is your teacher
Stackoverflow is your friend
Open Source Applications are you Code Gurus
Online Discussion Forums are your Communities
Organize events, competitions centered around Software development
Learn to use Collaboration Tools
Be disciplined inside and about your profession
Build Skills that sell
Join/Follow communities of developers
Learn to respect community, get max from it
Find what is the BUZZ in tech
Learn about Project Management seriously
Build products that can solves existing software problems in our community
Know about Documentation
Learn about software testing / Quality Assurance
Do one project by yourself per computer related subject
Give others, Take from others
Share your project code in the internet
No one becomes professional without a hard work
Those who are doing good now did their best while studying
No one is born talented, its the hard effort that pays later