Create your own JSF component in1.2 implementation

Have not tried your own JSF component in 1.2 version? Recommend you to have a look into below links to get to know about the component creation in JSF. After going through these links, I am sure you can able to create your own JSF component.

http://www.theserverside.com/news/1364786/Building-Custom-JSF-UI-Components

http://www.exadel.com/tutorial/jsf/HowToWriteYourOwnJSFComponents.pdf

http://www.ibm.com/developerworks/java/library/j-jsf4/

Cheers,

-NJN

Recommended website for J2EE framework website

This week, I was going through the recent J2EE technologies and framework updates from web. I was admired by seeing the website http://www.mkyong.com/ . It has very good J2EE framework updates for the experienced candidates who are keen to update their knowledgebase specifically in JSON, JSF2.0, Struts2.0 etc.

I am very happy and more delight to recommend the above mentioned information in my technical blog.

Happy reading!

Cheers,

-NJN

Create Bar code in Java based applications using BarCode4J

Guyz,

Today I have come across a requirement to print appointment confirmation letter with "Appointment Number" in a bar code format. I have goggled and come across a simple solution provided by BarCode4J. Generating different types of bar code is very simple using BarCode4J in java/j2ee applications. We strongly recommend you to go through the web link and explore the options available in BarCode4J. I strongly believe the sample application provided here are more than enough to understand the BarCode4J.

Hope this would be useful. Happy learning.

Cheers,
-NJN

Java Inner Class

/*
*
*
*/
package com.blx.learn.java.core.innerclass;

/**
* This is an example Java Inner class which demonstrate various Inner classes
* available
*
* @author Nanjundan Chinnasamy
* @version 1.0
*
*/
public class LearnInnerClass {

/**
* This is a sample Member Inner class defined inside a class
*
* This inner class is instance specific to the outer class
* (LearnInnerClass). Object can be created for this class using Outer class
* object.
*
* @author Nanjundan Chinnasamy
* @version 1.0
*/
class MemberInnerClass {

/**
* Member class method
*/
public void testMethod() {
System.out.println("This is member class testMethod method");
}

/**
* Static class method
*/
public void memberlassMthd() {
// To access member class method
this.testMethod();
// To access outer class method
LearnInnerClass.this.testMethod();
}
}

/**
* This is a sample Static Member Inner class defined inside a class. Member
* class defined as static. Like other static methods, member class has
* access to all.
*
* @author Nanjundan Chinnasamy
* @version 1.0
*
*/
static class StaticMemberInnerClass {

/**
* Static class method
*/
public void testMethod() {
System.out.println("This is static class testMethod method");
}

/**
* Static class method
*/
public void staticMemClassMthd() {
this.testMethod();
}

}

/**
* Method to testMethod local Inner class
*/
void localClassMethod() {

/**
* This is local class exists inside the method. This can be reference
* only within this method.
*
* @author Nanjundan Chinnasamy
* @version 1.0
*
*/
class LocalInnerClass {
public void testMethod() {
System.out.println("This is local class testMethod mthod.");
}
}
// To access local class methods
new LocalInnerClass().testMethod();
// To access outer class methods
testMethod();

}

/**
* Method to testMethod anonymous inner class
*
*/
void anonymousClassMethod() {

/**
* Anonymous Inner class declared inside a method without any name. JVM
* will create its own name during the compile time.
*
* Such implementation might required the places where to create an
* object instances w/o creating sub class and override their methods
*
* @author Nanjundan Chinnasamy
*
* @version 1.0
*/
Runnable runnable = new Runnable() {
@Override
public void run() {
System.out.println("This is anonymous inner class");
}
};
Thread thread = new Thread(runnable);
thread.run();
}

/**
* This is an out class testMethod method
*/
void testMethod() {
System.out.println("I am outer class testMethod method");
}

/**
* @param args
*/
public static void main(String[] args) {

// This is for static member class
LearnInnerClass.StaticMemberInnerClass staticMemberInnerClass = new StaticMemberInnerClass();
staticMemberInnerClass.staticMemClassMthd();

// This is for member class
MemberInnerClass memberInnerClass = new LearnInnerClass().new MemberInnerClass();
memberInnerClass.testMethod();

// This is for Local Inner class
LearnInnerClass outerClassForLocInnTst = new LearnInnerClass();
outerClassForLocInnTst.localClassMethod();

// This is for anonymous inner class
LearnInnerClass outerClassForAnomysClassTst = new LearnInnerClass();
outerClassForAnomysClassTst.anonymousClassMethod();

}

}


Output:
This is static class testMethod method
This is member class testMethod method
This is local class testMethod mthod.
I am outer class testMethod method
This is anonymous inner class

Way to Prevent Duplicate Request from Form in J2EE applications -2

Guys,

Here is the another solution to prevent duplicate form submission issue in web applications irrespective of the framework implementation.

Can you please try with the below code and update me in comments?

In JSP, we can have java script method during onsubmit like below.

And our java script implementation would be like below. submitForm method return true only very first time and form will be submitted. The same will be true for the sub sequent requests. Hope this will solve our issue.

//Global variable
var submitFlag = 1;

//Submit form method
function submitForm(form) {
if ( submitFlag == 1 ) {

submitFlag = 2;
return true;

} else {
return false;

}
}

Thanks,

-Nanjundan Chinnasamy

Way to Prevent Duplicate Request from Form in J2EE applications -1

Way to Prevent Duplicate Request from Form:

Here is the common and widely used mechanism used to preventing duplication form submission from a j2ee application. Ie, disabling the submit button during on click event. Example here is ICICI bank Internet banking application.

Though this is simple and a reasonable approach if we have a single submit button within a form, this may not work if we have more than one submit buttons in a form.

Are you looking for any other simple strategy to prevent duplication form submission from client side? Follow the next blog.

Cheers,

-Nanjundan Chinnasamy

Schedule a reoccur Task(s) using Java

Going forward(from today!) I am planning to write some technical blogs related to JAVA Technology. First, we might aware of Job Scheduling. I am sure all the projects require some job scheduling. Here is the sample example on Job Scheduling using Java Program:JobSchedule.java has main method and act as a gateway for this Scheduler Task example which will call schedule method in Timer Class(Available from JDK1.3). schedule method will take 3 arguments. First will the scheduled task to be perform and second will be the scheduled task to be called and third will be the scheduled time interval (all are in milli seconds). The scheduled task should extend the TimerTask class and the same needs to be override run method will perform the task.
In the below task whenever JobSchedule.java gets called, after 1 sec PrintTask gets called and you will be getting the output called "Calling PrintTask usinf JAVA Scheduler..". You will be getting the same o/p every 5 secs.

JobSchedule.java
package com.blx.jobSchedule;
import java.io.*;
import java.util.Timer;
public class JobSchedule {
private Timer timer;public JobSchedule() {
timer = new Timer();
}public static void main(String[] args) throws IOException {
JobSchedule jobSchedule = new JobSchedule();
// Test to be performed on schedule
// Inital/start schedule time or when to start
// Fixed time interval or schedular time
jobSchedule.timer.schedule(new PrintTask(), 1000, 5000);}
}

PrintTask. java
package com.blx.jobSchedule;
import java.util.TimerTask;
public class PrintTask extends TimerTask {
public void run() {
System.out.println("Calling PrintTask usinf JAVA Scheduler..");
}
}