Featured – Page 2

Native Keyword / Calling C Program From Java

October 9, 2013 Bibek Comments 0 Comment

You might have seen in Java API many methods are using native keyword. Lets understand them.

The native keyword is applied to a method to indicate that the method is implemented in native code using JNI.

Definition From JSR
A method that is native is implemented in platform-dependent code, typically written in another programming language such as C, C++, FORTRAN,or assembly language. The body of a native method is given as a semicolon only, indicating that the implementation is omitted, instead of a block.

Still looking more .. google it 🙂

Lets start with an example :

see this link

Stay Tuned… will post an example soon.

JavaScript Utility

October 9, 2013 Bibek Comments 0 Comment

Below are few Java Script methods to help you.

Debugging in JavaScript:
Debugging in JavaScript is now become easier with modern browsers.But still you will be facing issues in many cases so the alternative can be writing print statments in javaScript (i.e. console.log(“Message”)).

But in IE browser if you console is not opened (it can be opened with Developer tools (F12)) then it will show function undefined error and will stop further javascript execution. To prevent this you can use console as below.

window.console && console.log (“Message To Log”);

Getting Param From URL
function getParam(name) {
name = name.replace(/[\[]/, “\\\[“).replace(/[\]]/, “\\\]”);
var regexS = “[\\?&]” + name + “=([^&#]*)”;
var regex = new RegExp(regexS);
var results = regex.exec(window.location.href);
if (results == null)
return “”;
else
return results[1];
}

Example :

You must either modify your dreams or magnify your skills …

getParam(“load”) will return true;

Reload the Page Native Method
location.reload();

Lot more come.. Stay tuned…

Twitter Bootstrap

October 9, 2013 Bibek Comments 1 comment

From Wiki
Bootstrap is a free collection of tools for creating websites and web applications. It contains HTML and CSS-based design templates for typography, forms, buttons, navigation and other interface components, as well as optional JavaScript extensions.
It is the most popular project on GitHub and has been used by NASA and MSNBC among others.

Bootstrap was developed by Mark Otto and Jacob Thornton at Twitter as a framework to encourage consistency across internal tools. Before Bootstrap, various libraries were used for interface development, which led to inconsistencies and a high maintenance burden.

Bootstrap website

Bootstrap is simple to use. Look at few examples .

Bootstrap come with many ready to use features. See why to use at this link.

Ant Build Tool : Quick Notes

September 24, 2013 Bibek Comments 0 Comment

Ant Script for JAVA Developers

1) Simple Ant Script for Clean , Compile and jar generation adding Manifest information to jar

<project name="ANT Scipt" basedir="." default="jar-gen">
    <target name="-init">
   	 <echo>init called ..</echo>
    </target>

    <target name="clean-all" depends="-clean-classes,-clean-jar" />

    <target name="-clean-classes" description="Remove all class files.">
   	 <echo>Delete All Class Files ..</echo>
   	 <delete quiet="true" includeEmptyDirs="true" deleteonexit="true">
   		 <fileset dir="bin" excludes="**/.svn/**" />
   	 </delete>
   	 <mkdir dir="bin"/>
    </target>

    <target name="-clean-jar" description="Remove jar file.">
   	 <echo>Delete All Jar Files ..</echo>
   	 <delete quiet="true" includeEmptyDirs="true" deleteonexit="true">
   		 <fileset dir="dest">
   			 <include name="**/*" />
   		 </fileset>
   	 </delete>
   	 <mkdir dir="dest"/>
    </target>

    <target name="-compile-all" depends="clean-all">
   	 <echo>Compile All Java Files ..</echo>
   	 <javac destDir="bin" srcdir="src"
   		 fork="true" memoryMaximumSize="256m"
   		 debug="true" deprecation="true"
   		 failonerror="true" verbose="false"
   		 target="1.6" source="1.6">
   		 <include name="**/*.java" />
   		 <classpath>
   			 <fileset dir="lib">
   				 <include name="**/*.jar" />
   			 </fileset>
   		 </classpath>
   	 </javac>
    </target>

    <target name="jar-gen" description="jar in the dist directory." depends="-init,-compile-all">
   	 <echo>Generate Jar File ..</echo>
           <jar jarfile="dest/output.jar">
   	 <fileset dir="bin" includes="**/*.class" />
   	<manifest>
   	    <attribute name="Built-By" value="${user.name}" />
                <attribute name="Main-Class"  value="com.exmaple.MyController"/>
                <attribute name="Class-Path" value="../config/ ../lib/log4j-1.2.8.jar ../lib/mysql.jar" />
          </manifest>
        </jar>
    </target>
</project>

<echo>init called ..</echo>

</target>

<echo>Delete All Class Files ..</echo>

</delete>

</target>

<echo>Delete All Jar Files ..</echo>

</fileset>

</delete>

</target>

<echo>Compile All Java Files ..</echo>

<javac destDir="bin" srcdir="src"

fork="true" memoryMaximumSize="256m"

debug="true" deprecation="true"

failonerror="true" verbose="false"

target="1.6" source="1.6">

</fileset>

</classpath>

</javac>

</target>

<echo>Generate Jar File ..</echo>

</manifest>

</jar>

</target>

</project>

Note :- All folder path are relative to basedir . Here is basedir=”.”
Note :- the values at class-path are separated by space

2) Using Property in Ant Script

  	<target name="property-test">
   	 <echo>Start</echo>
   	 <property name="show" value="bibek" />
   	 <echo>Property Value.. ${show}</echo>
    </target>

<property name="temp_path" value="${root_path}//${life_cycle}//${client}//${year}//${month}//${day}" />

<echo>Start</echo>

<echo>Property Value.. ${show}</echo>

</target>

3) Reading From Property File

<!--  all properties are loaded heree -->
    <property file="scripts/config/config.properties" />

1 2	<!-- all properties are loaded heree --> <property file="scripts/config/config.properties" />

4) Current Time Stamp in Ant Script

    	<tstamp>
   		 <format property="current.time" pattern="yy-MM-dd_HH.mm.ss" />
   		 <format property="year" pattern="yyyy" />
   		 <format property="month" pattern="MM" />
   		 <format property="day" pattern="dd" />
   	 </tstamp>
   	 <echo>Current Time is : ${current.time} </echo>

</tstamp>

<echo>Current Time is : ${current.time} </echo>

5) Directory Opertaions
Make dir

           <mkdir dir="${input}" />
   	 <mkdir dir="${backup}" />

      Delete Dir
    	<delete quiet="true" includeEmptyDirs="true" deleteonexit="true">
   		 <fileset dir="${input}">
   			 <include name="**/*" />
   		 </fileset>
   	 </delete> 
File/Direcotorr Rename
<move file="${backup}/${jar.name}" tofile="${backup}/${jar.first.name}-${current.time}.jar" />

Copy files
 
   <copy todir="${input}" overwrite="true">
   		 <fileset dir="${src.dir}">
   			 <include name="${file_list}}" />
   		 </fileset>
   	 </copy>

Delete Dir

</fileset>

</delete>

File/Direcotorr Rename

Copy files

</fileset>

</copy>

6) Ant Script and Svn

SVN Checkout

  <target name="svnCheckout" depends="-init">
   	 <java classname="org.tmatesoft.svn.cli.SVN" dir="${checkout}" fork="true">
   		 <arg value="co" />
   		 <arg value="--username" />
   		 <arg value="${svn.username}" />
   		 <arg value="--password" />
   		 <arg value="${svn.password}" />
   		 <arg value="${repository.URL}" />
   		 <classpath>
   			 <fileset dir="scripts/${lib.dir}">
   				 <include name="**/*.jar" />
   			 </fileset>
   		 </classpath>
   	 </java>
    </target>

</fileset>

</classpath>

</java>

</target>

Note :- for https:/ type svn
7)File uploads and Ant Script

	<target name="server to local">
   	 <scp file="${sftp.userid}:${sftp.password}@${sftp.server}:${remote.input.dir}/*.xml"
   		 todir="${backup}" port="${sftp.port}" trust="true">
   	 </scp>
   	 <delete includeemptydirs="false">
   		 <fileset dir="${backup}" excludes="${file_list},*.jar" />
   	 </delete>
    </target>

    <target name="local to server " description="Upload files to Server">
   	 <scp todir="${sftp.userid}:${sftp.password}@${sftp.server}:${remote.input.dir}"
   		 port="${sftp.port}" trust="true">
   		 <fileset dir="${input}" includes="${file_list}" />
   	 </scp>
    </target>

<scp file="${sftp.userid}:${sftp.password}@${sftp.server}:${remote.input.dir}/*.xml"

todir="${backup}" port="${sftp.port}" trust="true">

</scp>

</delete>

</target>

<scp todir="${sftp.userid}:${sftp.password}@${sftp.server}:${remote.input.dir}"

port="${sftp.port}" trust="true">

</scp>

</target>

8) Variable of Varible in Ant Scipt

<target name="load_lifecyle_data">
   	 <echo>
              	hi
   	 </echo>
<macrodef name="propertyload">
   		 <attribute name="userid" />
   		 <attribute name="password" />
   		 <element name="some-tasks" optional="yes" />
   		 <sequential>
   			 <property name="name" value="${@{from}}" />
   			 <property name="sftp.userid" value="${@{userid}}" />
   			 <property name="ency.password" value="${@{password}}" />
   			 <echo>
   				 userid is :- ${userid}
   				 password :-${password}
   			 </echo>
   		 <some-tasks>
   			 <echo>Lifecylce Specific Information Feteched...</echo>
   		 </some-tasks>
   		 </sequential>
   	 </macrodef>
   	 
   	 <propertyload userid="${life_cycle}.userid"
   		 password="${life_cycle}.ency.password" >
   		 <some-tasks>
   			 <echo>Lifecylce Specific Information Feteched...</echo>
   		 </some-tasks>
   	 </propertyload>
    </target>

<echo>

</echo>

<echo>

userid is :- ${userid}

password :-${password}

</echo>

<some-tasks>

<echo>Lifecylce Specific Information Feteched...</echo>

</some-tasks>

</sequential>

</macrodef>

<propertyload userid="${life_cycle}.userid"

password="${life_cycle}.ency.password" >

<some-tasks>

<echo>Lifecylce Specific Information Feteched...</echo>

</some-tasks>

</propertyload>

</target>

9)creating war and zip file in ant script

<target name="dist" depends="copy-resources">
   	 <war destfile="dist/mywar.war" webxml="web/WEB-INF/web.xml">
   		 <fileset dir="web">
   			 <include name="**/**"/>
   			 <exclude name="**/web.xml"/>
   		 </fileset>
   	 </war>
   	 <zip destfile="dist/my_config.zip">
   		 <fileset dir="config/src"/>
   	 </zip>
    </target>

</fileset>

</war>

</zip>

</target>

10) Creating Custom Ant Tasks

	<target name=custom task" depends="load_lifecyle_data">
   	 <echo>custom task..</echo>
   	 <taskdef name="mytask" classname="com.example.AntScriptUtils" classpath="bin">
   		 <classpath>
   			 <pathelement location="com.example" />
   			 <fileset dir="${lib.dir}">
   				 <include name="*.jar" />
   			 </fileset>
   		 </classpath>
   	 </taskdef>
   	 <mytask message="${sftp.ency.password}" />
   	 <property name="sftp.password" value="${dPassword}" />
   	 <echo>Password Decrypted Successfully... ${sftp.password}</echo>
    </target>

<echo>custom task..</echo>

</fileset>

</classpath>

</taskdef>

<echo>Password Decrypted Successfully... ${sftp.password}</echo>

</target>

AntScriptUtils.java
    
package com.example;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Task;



public class AntScriptUtils extends Task {
    private String pass;
    String decryptedPassword = null;

    // The method executing the task
    public void execute() throws BuildException {

    
   	 try {
   		 decryptedPassword = decrypter.decryptValue(pass);
   		 getProject().setProperty("dPassword", decryptedPassword);

   	 } catch (PropertyEncrypterException e) {
   		 e.printStackTrace();
   		 ErrorLogger.fatal("Error : ", e);
   	 }
    }

    // The setter for the "message" attribute
    public void setMessage(String msg) {
   	 this.pass = msg;
    }

    public static void main(String[] args) {
   	 new AntScriptUtils();
    }

}

AntScriptUtils.java

package com.example;

import org.apache.tools.ant.BuildException;

import org.apache.tools.ant.Task;

public class AntScriptUtils extends Task {

private String pass;

String decryptedPassword = null;

// The method executing the task

public void execute() throws BuildException {

try {

decryptedPassword = decrypter.decryptValue(pass);

getProject().setProperty("dPassword", decryptedPassword);

} catch (PropertyEncrypterException e) {

e.printStackTrace();

ErrorLogger.fatal("Error : ", e);

}

// The setter for the "message" attribute

public void setMessage(String msg) {

this.pass = msg;

}

public static void main(String[] args) {

new AntScriptUtils();

}

Required Jar files for ant’s different task
antlr-runtime-3.1.3.jar commons-net.jar ganymed.jar jna.jar
jsch-0.1.44.jar sqljet.1.0.4.jar svnant.jar svnClientAdapter.jar
svnjavahl.jar svnkit.jar svnkit-cli.jar
svnkit-javahl.jar trilead.jar

Blank final field in Java

September 18, 2013 Bibek Comments 0 Comment

A variable that is declared as final and not initialized is called a blank final variable. A blank final variable forces the constructors to initialize it.

In other words
The final property of class must have a value assigned before object is created. So the last point where you can assign value to them is constructor.

This is used often for immutable objects.

 public class Foo {

  private final Bar bar;

  public Foo(Bar bar) {
    this.bar = bar;
  }

  public Bar getBar() {
   return new Bar(bar);
 } 
}

public class Foo {

private final Bar bar;

public Foo(Bar bar) {

this.bar = bar;

}

public Bar getBar() {

return new Bar(bar);

}

Bibek

Anyone who has never made a mistake has never tried anything new….

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Category: Featured

Native Keyword / Calling C Program From Java

October 9, 2013 Bibek Comments 0 Comment

JavaScript Utility

October 9, 2013 Bibek Comments 0 Comment

Twitter Bootstrap

October 9, 2013 Bibek Comments 1 comment

Ant Build Tool : Quick Notes

September 24, 2013 Bibek Comments 0 Comment

Blank final field in Java

September 18, 2013 Bibek Comments 0 Comment