Tech-Tack-Talk

EJB3: Good to know details

2012-01-16T01:19:00.000-08:00

Message Driven Bean

* Important EJB and JMS import files when creating MDB

import javax.ejb.ActivationConfigProperty;

import javax.ejb.MessageDriven;

import javax.jms.Message;

import javax.jms.MessageListener;

import javax.jms.ObjectMessage;

* How to create an MDB class?

- use the @MessageDriven annotation

@MessageDriven(activationConfig = {

@ActivationConfigProperty(propertyName = "destination", propertyValue = "queue/OrderBillingQueue"),

@ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue") })

public class OrderBillingMDB implements MessageListener {

*How to send a message for a particular MDB in a particular JMS Queue?

(1) Declare a JMS resource including the message destination, by using Dependency Injection (DI) with the use of @Resource annotation instead of being looked up.

@Resource(name = "jms/QueueConnectionFactory")
private ConnectionFactory connectionFActory;

@Resource(name="jms/OrderBillingQueue")
private Destination billingQueue;

(2) Create a connection using ConnectionFactory Object

Connection connection = connectionFactory.createConnection();

(3) Create a session using the connection

Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

(4) Create a MessageProducer using the session for a particular queue

MessageProducer message = session.createMessageProducer(billingQueue);

(5) Create an ObjectMessage and set the Object that will be created as a message

ObjectMessage message = session.createObjectMessage();
// assuming that order has already been
// instantiated and already has values.
message.setObject(order);

(6) Send the message via the MessageProducer Object

producer.send(message);

(7) Release the JMS resources

producer.close();
session.close();
connection.close();

NOTE: the code snippet are enclosed in a try and catch clause

* Common Error encountered in deploying Message Driven Bean (on Jboss AS)

INFO [EJBContainer] STARTED EJB: com.jeeconsultant.jms.SAmpleMDB ejbName: SampleMDB

WARN [JmsActivation] Failure in jms activation org.jboss.resource.adapter.jms.inflow.JmsActivationSpec@b7b17a(ra=org.jboss.resource.adapter.jms.JmsResourceAdapter@1af76e7 destination=queue/MyQueue destinationType=javax.jms.Queue tx=true durable=false reconnect=10 provider=java:/DefaultJMSProvider user=null maxMessages=1 minSession=1 maxSession=15 keepAlive=60000 useDLQ=true DLQHandler=org.jboss.resource.adapter.jms.inflow.dlq.GenericDLQHandler DLQJndiName=queue/DLQ DLQUser=null DLQMaxResent=5) javax.naming.NameNotFoundException: MyQueue not bound at org.jnp.server.NamingServer.getBinding(NamingServer.java:771)

Reason:

The Queue Destination in Jboss was not defined yet.

Solution:

adding the following XML code-snippet to destinations-service.xml file

usually located at C:\jboss-5.1.0.GA\server\default\deploy\messaging

<mbean code="org.jboss.jms.server.destination.QueueService"

name="jboss.messaging.destination:service=Queue,name=SampleQueue"

xmbean-dd="xmdesc/Queue-xmbean.xml">

<depends optional-attribute-name="ServerPeer">jboss.messaging:service=ServerPeer</depends>

<depends>jboss.messaging:service=PostOffice</depends>

</mbean>

Web Service: Good to know details

2012-01-16T01:13:00.000-08:00

How to Generate WS classes from an existing Service (End point) ?

- Use wsimport tool/command - this is shipped with JDK 1.6

ussage: run wsimport in command line

wsimport -keep -verbose -d [directoryfor output files] [WSDL url]

(wsimport parameters/optionsdiscussed at http://download.oracle.com/javase/6/docs/technotes/tools/share/wsimport.html)

Example:

wsimport -keep -verbose -dC:\PROJECTS\Workspace\PortServices\SubscriberProfileConfigService\src http://localhost:9080/SubscriberProfileConfigurationServiceMediationWeb/sca/SubscriberProfileConfigurationServiceWSExport/WEB-INF/wsdl/SubscriberProfileConfigurationServiceWSExport_SubscriberProfileConfigurationServiceHttp_Service.wsdl

>> JBoss Web Server (tip-top-tips)

2009-05-21T03:15:00.000-07:00

JBoss Web Server or JBoss Web Application Server is one of the pioneering Open Source Application Servers here on earth (I just don't know if they have this at planet Crypton). JBoss started to blossom a year before I decided to end the long journey of my college life (way back 1999). JBoss has been catering to numerous web applications all throughout this planet for years now. And one good thing about it is - it's FREE! - The best things in this cyber-life are free =)

Here are some tips/trivia about the bossy JBoss:

server.xml

The configuration file where we set the ports for different protocols is called server.xml. This file is located in [JBoss_Root]/server/default/deploy/jboss-web.deployer folder.

The most widely used protocol in the World Wide Web is the Hyper-Text-Transfer-Protocol or HTTP. On the server.xml, it is initially set to the default port used for HTTP which is 8080, but you can change this to any possible available port. See example bellow:

< Connector port="8080"
address="${jboss.bind.address}"
maxThreads="250" maxHttpHeaderSize="8192"
emptySessionPath="true" protocol="HTTP/1.1"
enableLookups="false" redirectPort="8443" acceptCount="100"
connectionTimeout="20000" disableUploadTimeout="true" />

This Article is a work on progress...

>> Creating an Installer for your Application

2009-05-19T20:28:00.000-07:00

There are several tools that could be used in creating an installer for your application. Some of them can be purchased and some are free (open-source).

I've tried using a Licensed Installer creator called InstallAnywhere and I also tried using an open-source called IZPack.

IZPack for me is better because of two things:

1. It's totally FREE!
2. It's platform independent. All it needs to run is a Java[tm] Runtime Environment.

You can download IZPack here or you can visit the IZPack homepage here.

IZPack installer comes in a jar file (java archive) and it's name is something like IzPack-install-[version-number].jar.

IzPack uses XML files to describe installations, so if you're planning to use this tool, you should be familiar with XML (ant build files).

Let's have a walk-through on the basic kung-fu of this IZPack thing...

- INSTALLING IZPack -

1. Ensure that you have set the JAVA_HOME and add it on the PATH/CLASSPATH

2. Open a command-line and go to the directory where the jar file is located

3. Type the following command:

java -jar [Installer name]

Note:
[Installer name], is the IZPack jar file.

4. Follow-on the GUI (it's easy and straight-forward)

- COMPILING YOUR FIRST INSTALLER -

1. You should have created an XML file (build file to describe the installation process) eg. install.xml or build.xml

Note:
A good start to read about IZPack XML tags could be found at [IZPAck_Install_Root]/doc folder.

2. Open a command line and go to the /bin directory from the installed IZPack folder.

Note:
You can also add the file called compile (from the /bin folder) to the PATH/CLASSPATH , so that you don't need to go to the /bin folder every time you want to create an installer.

3. Enter the following command bellow:

compile install.xml -b . -o install.jar -k standard

Note:
The installer that you have created (install.jar) will run on any machine/operating system that has JVM.

The compilation options for a command-line:

-? : gives a list of the available options.

-b : specifies the base path, ie the one that will be used to resolve the relative paths. If your XML file contains absolute paths, specify it to an empty string (-b "").

-k : specifies the installer kind, for instance most users will want standard here.

-o : specifies the resulting installer Jar file name.

- RUNNING YOUR APPLICATION INSTALLER -

Just double-click the jar file (install.jar) OR you can open a command line, go to the directory where the installer is located and type the following command:

java -jar install.jar

>> PostgreSQL - one of the developer's kung-fu...

2009-05-19T19:11:00.000-07:00

In most web applications or client-server applications that handles data; User interface and user experience are considerably big factors. But, these should be secondary from the main concern. I believe that the most important part of any application that handles and processes data is the data itself.

Developers have a wide range of choices when it comes to database applications. Oracle , SQL Server and MySQL are some of the popular databases that are out in the market.

But nowadays, PostgreSQL is one of the best open-source DB that a developer should consider. It's free, easy to use, portable and platform independent.

You can download PostgreSQL from here.

Let's see some of the basic kung-fu of this database:

1. Installation process

Installing the database is very simple. You can take advantage of the graphical user interface. It's very easy and straight-forward specially for windows. For Linux, there are some simple configurations that we need to consider.

Learn more about the installation process from here.

2. Security (Access control)

After installing the database, there is a configuration file named pg_hba.conf. This is found on [postgreSQL_root]/data folder for Windows; For Linux usually it's at /var/lib/postgresql/data. We configure the client connection authentication in this file.

Some of the common configuration options are listed bellow:

* We can set which clients can connect to one or more database.
* Allow clients to connect to a single or multiple databases using a user-name and password authentication.
* Allow clients to connect to a single or multiple databases even without a user-name and password authentications.

You will see the following configuration variables in pg_hba.conf file:

TYPE:
- this refers to the connection type.

DATABASE:
- refers to a database or multiple database separated by comma.

USER:
- refers to the user or list of users that are allowed to connect to the db.

CIDR-ADDRESS:
- specifies the set of hosts the record matches; usually an IP address.

METHOD:
- refers to the method of connection. either to accept password, trusted connection, etc.

A synopsis can be found from the initial pg_hba.conf file after installing PostgreSQL.

3. Schema and Table Creation

There are two basic ways to create Schema and Tables.

1. PGAdmin-III is a good tool in creating Schema and Tables. You can also use this tool to create a database. It usually comes along with the installer. It's very easy to use.

2. SQL scripts will always be in the picture when it comes to creating schema and tables. A user must use the psql command to run a script directly on the command line (The sql script could be typed directly on the console or you can use a .sql file). Bellow is an example on how to run script:

psql databasename username < filename.sql

Note:
psql is an executable file that could be found in the /bin folder from PostgresSQL install location.

4.Stored Procedure

FYI:Postgres SQL does not support the CREATE PROCEDURE syntax. It does not have the typical Stored Procedure like what other databases have. But Postgresql Function() can be used to create a stored-procedure like capabilities.

To learn more about creating stored procedures for postgresql, visit T-H-I-S

More kung-fu to follow....

>> Unix Shell in your Windows Environment

2009-02-12T01:34:00.000-08:00

Cygwin has been so helpful among Linux users who can't avoid to put their hands on Windows platform.

Because of Cygwin, a user can run unix commands on Windows environment. It's like having a Unix Console within Windows system. (Not 100% unix console but it will surely help.)

You can download and install Cygwin from this site http://cygwin.com

For those Microsoft users who want to try Cygwin, here are some Simple and Helpful commands:

*** If you want to navigate on directories via cygwin, type the command bellow (for example you want to navigate on drive C:)

cd /cygdrive/c

*** If you want to search on a file that has a specific word in it, you can try the command bellow:

grep "word to search" .

Note:

grep → is like a find command.

"word to search" → could be changed to any word that you want to search. Make sure that the word is enclosed in double quotes.

*.* → this means that you are searching in all files inside the directory. You can change it to *.doc to search only on doc files.

After running the command, Cygwin will display the list of files that contains the word that you searched.

*** If you want to connect to a linux box from your windows system, Cygwin could be of help. Just use the codes bellow:

ssh userName@IPNumber

Note:

userName → could be any valid user in the Linux Machine.

IPNumber → is the IP number of the Linux Machine or you can use the Machine name.

After running this command, you will be asked to enter a password; If the user has a password, just supply the valid password and click ENTER.

*** If you want to transfer files from a windows system to a Linux box, try the steps and codes bellow:

1. Go to the source directory (eg. the source directory is C:)

cd /cygdrive/c

2. Copy the file to the linux box by entering the command bellow

scp FileName userName@IPNumber:/home/user1/folder1

Note:

FileName → is the valid File Name of any file you want to copy.

userName → could be any valid user in the Linux Machine.

IPNumber → is the IP number of the Linux Machine or you can use the Machine name.

/home/user1/folder1 → is the path to where you want the file to be copied.

*** If you want to view a log from your windows system during runtime (typically a server log), you can try the simple codes bellow:

DOS doesn't have a tail command which could be used to view logs during runtime; that is why Cygwin will be of help for this. For example, the name of the log that you want to check is SystemOut.log, just enter the code bellow:

tail -f SystemOut.log

Note:

On the Cygwin console, you should be on the directory where SystemOut.log is located.

*** If you want to check the status of a running application, you can try the command bellow:

ps -e | grep name

*** If you want to create a password protected ZIP file, run the following command:

zip -r -e [desired file name].zip [file to be zipped]

>> JSF How To's

2009-02-12T00:05:00.000-08:00

Prerequisites:

Ensure that you have the following applications installed in your system:
1. Jboss 4.2.+
2. Eclipse Europa
3. JVM, JDK, JRE 1.5

How to add JSF libraries on Eclipse Europa + JBoss4.2:

1. On eclipse menu Click Window → Preferences
2. On the opened window, select Web and XML → Java Server Faces → Libraries
3. On the new window, select Add
4. Browse through Jboss4.2.0 directory
5. Go to server → default → deploy → jboss-web.deployer → jsf-libs
6. Select the three jar files (jboss-faces.jar, jsf-api.jar, jsf-impl.jar)
7. Give a Library Name for the selected jars (eg. jbossJSF)
8. Click finish
9. Include JSTL library; click New
10. On the new window, click Add
11. Go to Jboss4.2.0 directory
12. Go to server → default → deploy → jboss-web.deployer
13. Select jstl.jar
14. Give library name for the selected jar (eg. JSTL)
15. click Finish → OK

How to Create New Dynamic Web Project:

1. On the eclipse menu, click File → New → Other
2. On the new window, select Web → Dynamic Web Project
3. Click Next
4. Put Project Name (eg. demoJSF)
5. On Target RunTime, Select Jboss4.2.0
6. Click Next
7. Check the following check boxes (Dynamic Web Module, Java, Java Server Faces)
8. For Jboss4.2, use Ver1.2
9. Click Next → Finish

How to Add a JSP Page:

1. On your eclipse Java perspective, right Click the Project then choose New → JSP
2. put JSP name (eg addCustomer.jsp), then click Next
3. Select, New JSP File (html)
4. Click Finish
5. Do steps 1 to 4 to add another page (eg. listCustomer.jsp)

How to Create Page flow on the application:

1. Go to Projectroot\WebContent\WEB-INF\
2. Double click faces-config.xml
3. Select Start
4. Open Palette
5. From the palette, drag Page icon on the form.
6. Select addCustomer.jsp from the list of pages
7. Drag Page icon again
8. Select listCustomer.jsp
9. From the palette, Click Link
10. Link addCustomer.jsp to listCustomer.jsp
11. Put on Form, Outcome “success”

How to Add Managed Bean:

1. Go to Projectroot\WebContent\WEB-INF\
2. Double click faces-config.xml
3. Click the managed bean tab
4. Click Add
5. Select Create New Java Class
6. Click Next
7. Put valid package and valid bean name (eg. CustomerBean.java)
8. Click Next → Next → Finish
9. Go to the newly created class
10. Create Variables and Generate Setters and Getters
11. Add a method named add() that returns a String (we may insert business logic on this method)

Tech-Tack-Talk

EJB3: Good to know details

Web Service: Good to know details

>> JBoss Web Server (tip-top-tips)

This Article is a work on progress...

>> Creating an Installer for your Application

>> PostgreSQL - one of the developer's kung-fu...

1. Installation process

2. Security (Access control)

3. Schema and Table Creation

4.Stored Procedure

Other Notable Configuration and Tips for Postgresql

More kung-fu to follow....

>> Unix Shell in your Windows Environment

cd /cygdrive/c

grep "word to search" *.*

ssh userName@IPNumber

cd /cygdrive/c

scp FileName userName@IPNumber:/home/user1/folder1

tail -f SystemOut.log

ps -e | grep name

zip -r -e [desired file name].zip [file to be zipped]

>> JSF How To's

grep "word to search" .