scan the code to unleash the joke using your mobile! http://bit.ly/w28Vsb 

Hibernate is an object-relational mapping (ORM) library for the Java language, providing a framework for mapping an object-oriented domain model to a traditional relational database. Hibernate solves object-relational impedance mismatch problems by replacing direct persistence-related database accesses with high-level object handling functions.

Hibernate’s primary feature is mapping from Java classes to database tables (and from Java data types to SQL data types). Hibernate also provides data query and retrieval facilities. Hibernate generates the SQL calls and attempts to relieve the developer from manual result set handling and object conversion and keep the application portable to all supported SQL databases with little performance overhead.

well, as we know what is hibernate and what is the primary feature is, let’s go deeper from developers’ perspective, inspecting three areas:

1. Configuring hibernate for your application: please note that I will configure hibernate as a stand alone database layer, don’t assume I am getting it ready for production use into web application.
2. Querying a database: single simple queries to complex joins.
3. Updating a database using save and update.

In this article we will do hibernate configuration with simple DB interaction, persisting data. I will cover different ways of query DB and updating/saving data to DB in later articles.

Getting ready, Organized!

Simply open your preferred Java IDE and start a new Java project and create a lib directory that will contain required jars for our application and config directory that will contain any config files we might need.

your application hierarchy should look something like this

now, let’s start the real work

• create users table on database, that we will use as an example to interact with DB.

CREATE TABLE  `example_db`.`users` (
`id` INT NOT NULL AUTO_INCREMENT ,
`username` VARCHAR( 255 ) NOT NULL ,
`password` VARCHAR( 255 ) NOT NULL ,
PRIMARY KEY (  `id` )
);

• you need to tell hibernate what class maps to which table, you can achieve this using POJO class, as follows:

package com.dwairi.example.hibernate.model;
 
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.Table;
import org.hibernate.Session;
import com.dwairi.example.hibernate.HibernateUtil;
 
@Entity
@Table(name="users")
public class User {
 public void save(){
  Session session = HibernateUtil.getSessionfactory().getCurrentSession();
  session.getTransaction().begin();
  session.save(this);
 }
 
 @Id
 @GeneratedValue
 private Integer id;
 @Column(name="username")
 private String userName;
 
 @Column(name="password")
 private String password;
 
 public Integer getId() { return id; }
 public void setId(Integer id) { this.id = id; }
 public String getUserName() { return userName; }
 public void setUserName(String userName) { this.userName = userName; }
 public String getPassword() { return password; }
 public void setPassword(String password) { this.password = password; }
}

• hibernate provide a layer to interact with DBs, that is sessionFactory, that we will be using in this example; it provides a transactional environment and gives you the power of ORM in a simplified way.
  Following is a helper class that will handle creating one sessionFactory object in the course of application life:

package com.dwairi.example.hibernate;
 
import java.io.File;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import com.dwairi.example.hibernate.model.User;
public class HibernateUtil {
 private static final SessionFactory sessionFactory;
 static {
  try {
   AnnotationConfiguration annotationConfiguration = new AnnotationConfiguration();
   annotationConfiguration.configure(new File("config/hibernate.cfg.xml"));
   annotationConfiguration.addAnnotatedClass(User.class);
   sessionFactory = annotationConfiguration.buildSessionFactory();
  } catch (Throwable ex) {
   System.err.println("Initial SessionFactory creation failed." + ex);
   throw new ExceptionInInitializerError(ex);
  }
 }
 public static SessionFactory getSessionfactory() {
  return sessionFactory;
 }
}

• as you might noticed, it seems we have used a file hibernate.cfg.xml , what is this? actually, it’s the configuration file for hibernate that will help you configure how to interact with DB using hibernate. here how it will look like

<!--?xml version="1.0" encoding="UTF-8"?-->
 
	  com.mysql.jdbc.Driver
 
	  jdbc:mysql://localhost/example_db
	  root
	  org.hibernate.dialect.MySQLDialect
	  1
	  true
	  true
	  org.hibernate.transaction.JDBCTransactionFactory
	  thread
	  org.hibernate.cache.NoCacheProvider

• create application runner, I will call it Test.

package com.dwairi.example.hibernate;
import com.dwairi.example.hibernate.model.User;
public class Test {
 public static void main(String[] args) {
 User user = new User();
 user.setUserName("dwairi");
 user.setPassword("password");
 user.save();
 System.out.println("user object saved to DB: " + user.getId());	}
}

• we will add a log4j.properties file to the root of classpath and turn on debug mode, in order to see what going on, it will look something like this

log4j.rootLogger=DEBUG, A1
# A1 is set to be a ConsoleAppender
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-4r [%t] %-5p %c %x - %m%n

Time to see what have we got, run the application, read the debug data logged by hibernate and watch it successfully persists data to DB.

Happy DB-hibernate-ing!

1. Create .htpassword file in a root protected path and add the first user
   ^?View Code LINUX

   su - mkdir /var/www/htpassword/ htpass -cm /var/www/htpassword/.htpassword admin

2. add more users to .htpassword file
   ^?View Code LINUX

   htpass -m /var/www/htpassword/.htpassword username

3. add .htaccess to your host public directory (or document root), it will look similar to this
   ^?View Code LINUX

   AuthName "Restricted Area" AuthType Basic AuthUserFile /var/www/htpass/.htpasswd AuthGroupFile /dev/null require valid-user

   this is simple and obvious, but in case of ruby on rails you need to add it to your public directory not rails project root directory.

now, you need to restart your apache websrever to update to latest configuration, then point your browser to your website and check it’s working, it should prompt you for username and password.

have a nice sys admin!

While being organized is an important aspect of anyone’s life style, it’s an important aspect of every developer’s life to ensure – in the first place – a lesser-stressed day to day work (uh, well!).

in this article I am telling the story of setting up a development environment for a Ruby on rails application, but you can apply the same concepts for any project, regardless of the programming language you use, regardless of the techniques you use and regardless of any 3rd party integration requirements.

to start simply, after receiving project requirements, doing your researches and decide on technology to use, you need to start thinking about the process of development, deployment and testing, until the first production ready product is in place.

Development

Obviously you need to install Ruby on Rails framework (here we use the latest stable ruby version 1.9.2 and rails 3.x at the time of writing this article) to start developing a Ruby on Rails based-project, so, here are the steps to install RoR for your Linux Machine (Ruby on Rails on Windows machines works on a one-click installer).

• using Linux famous software manager yum, we will install the OS dependencies for ruby

  su - root
  yum install zlib zlib-devel openssl openssl-devel readline readline-devel

• download ruby 1.9.2x from source.
• compile ruby source and install additional libraries using the following commands
  ^?View Code LINUX

  cd ruby-1.9.2-p0 ./configure make make install cd ext/zlib ruby extconf.rb make make install cd ../openssl make make install cd ../readline make make install sudo gem install rails cd ext/zlib ruby extconf.rb make make install cd ../openssl make make install cd ../readline make make install

  ruby 1.9.2 ships with gem! that means you don’t need to install gem.

• install rails using gem command that just installed with ruby
  ^?View Code LINUX

  gem install rails

• logout from super user root and create your ruby on rails application

• ^?View Code LINUX

  rails new my_app rails server

• go to http://127.0.0.1:3000/ to test that your installation is working as expected, you should get the default ruby on rails page.
• you need an IDE (I prefer Aptana for rails, Eclipse for Java, and vim editor for php and python )

Deployment

Deployment process is meant to make your development process more comfortable, know who did what, keep track of code revisions and safely rollback to any revision of the software – simply ensure your product is stable in production (that is in front of your customers), and maintainable.

on the other hand, you need to have software configuration system that is to manage source code revisions, smoothly aggregate multi-developers work and have a better rollback process.

speaking web application is meant to run into an application server, that will serve your users request, for ruby on rails, I will set up apache http server with Phusion (know as mod_rails) on next article.pro

Common saying: “most projects failures is management failures”, well, the first step is to get yourself organized.

have a nice and organized coding!

In ORM, a one Class instance is mapped to one Relational Database table record. for example, suppose we have a table called “users” that have three columns “id”, “full_name” and “email_address”, to express this table into Object a Class that have three member variables that is mapped to the three table’s columns, converting columns values from Database data types into system types when querying for records and back into columns data types when saving or updating record.

Every software technique has come to solve an issue, reduce cost, time and effort. ORM – alike – is here for the sake of making Developers’ life easier when it comes to dealing with Databases.

Many ORM softwares – both commercial and open source – are off the shelf to pick and use, and as always, each software has its own hassle, for instance looking at libraries implemented using Java language you can find many ranging from complex to plain ORM implementations.

obstacles raise when it comes to implementing ORM softwares, this can be viewed from database and software side; as for database side: we can talk about securing data integrity, doing Joins and bulk operations. and from software point of view we can talk about performance, debugging and concurrency.

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class Date
  def self.walk_days(start_date, end_date, format = "%m/%d/%Y")
    dates = []
    s = Date.strptime(start_date, format)
    e = Date.strptime(end_date, format)
    cur = s
    while true
      if cur === e
        dates << cur
        break
      end
      dates << cur
      cur = cur.next_day
    end
    dates
  end
end

this code snippet use mixins and it can be used as follows

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Date.walk_days("01/21/2011", "02/09/2011").each do |d|
  puts "Day: " + d.strftime("%B %d, %Y")
end

Take in mind that you might and might not know a thing about the topic you are requested to research; here I will point my finger to a good starting point.

first thing first: Google the exact phrase but don’t mess with a long article on howto and so on. you only need to find out what is and why. for me and in many topics I check a slideshare document (that is my favourite place) and start writing questions to answer.

actually, every research start with a question and a good researcher is the one who can ask the right questions – easy, ha!

Ok, let’s put on hands a real example, recently I decided to take a look at Spring-OSGi (Spring Dynamic Modules) as an example on SOA.

Google it: Spring Dynamic Module and pick the slideshar presentation, below is the questions we need to answer about this topic:

1. What is Spring-OSGi?
2. Its lifecycle
3. what are the pros and cons of using it over other OSGi implemntations?
   you don’t need to read about every other alternative in the world in this stage of research, you could look for reviews on the topic. and that can lead you to research another topic, but be careful not to fall in the Dip!
4. how to use it – a tutorial?

answering the above questions will lead you to a good understanding for Spring-OSGi and you should be able (as a software developer) to write a POC of it.

for me, the above questions shouldn’t take more than 15 working hours to get the POC up and running.

- Osama

• Not every person who have an idea is the 2nd Steve Jobs.
• Life does not work like this: “if you build it, they will come”, you should be careful to fancy your ideas to yourself!
• lack of customer validation is one of the biggest reasons for startup failures, you need to figure out what – potential – customers really need.
• One example of successful startup is Campfire Labs, check them out!
• a five-steps process is to become more successful – like Jobs? OK, stick to high standards, be disciplined, an idea should solve customers’ problem and try to have as few as possible products at one time.

well, that is a good article, but who will work on these guidelines? most new entrepreneur know the above mentioned, but who can stick to it? what could prevent you from sticking to these guidelines?

Good Luck for All!

well, since I used to read alot – when having time, of course – , I will be putting here what a normal man can understand from an article, say 400 word in 50 word only – certainly, don’t count on that!

good reading for All

- Osama

last weekend I was messing with CodeIgnitor following a great series of articles that explains how to work with CodeIgniter and Doctrine step by step.

I advice you to have a look at it, you can install it on windows with WAMP and have it up and running in less than 5 minutes!

why I am looking at it? ok, I have a curse that is looking for new things, and flipping every stone and rock I notice.

that said, my last week was a productive weekend, I have a thing in my pocket for PHP development Now.