XML, Databases and Enterprise Java for Mac OS X

The leap to Mac OS X introduces a new world of possibilities to Apple users. Both the Unix heritage of Darwin and the sleek integration of Java bring the OS X platform a number of powerful Open Source packages and with them, opportunities to work with some exciting cutting-edge technology. As exciting as these opportunities are, they can also be daunting. The very term "cutting edge" implies that a long time may pass before we see a friendly "Dummies" book published to help us get started.

As a Linux and Java enthusiast coming to the Apple platform, I would like to offer something to my new Apple community. Already I've put together a package installer to facilitate installing and using Jakarta Tomcat and Cocoon. I will continue to work to help interested Mac people explore relational databases (MySQL and PostgreSQL), Java Servlets and Java Server Pages (Jakarta Tomcat), XML (Apache XML's Cocoon) and Enterprise Java Beans (JBoss) and how to use these powerful and FREE applications to create cutting-edge web sites.

These articles are meant to help you get started with a real-world implementation of these technologies. Obviously there isn't time for me to actually teach any fundamentals. I will assume that you will take the initiative to go over to the local Barnes & Noble and dig up some promising books where talented authors have gone through great pains to give you the training you need to get up to speed. I will provide book recommendations (please e-mail me if you think I'm missing a particularly good book in any of my lists). I will also assume that you have functional ability to program in Java. If you can't immediately tell me the difference between a static method and a class method, go back and read your Java in a Nutshell.

I should mention that although emphasis is given to installation and configuration under Mac OS X, much of this material can apply to any flavor of Unix that has a good Java implementation or even (God forbid!) Windows. This means that any implementation of these particular software packages can be migrated to larger server hardware with a trivial amount of effort. Try that with Winblows!

Here's a rough outline of the topics that I will try and cover over the next months:

MySQL Installation and Access via JDBC (5/12/2001: notes,outline): MySQL is a nice compact relational database (SQL) server. It tends to be lean, fast, easy to install and configure, and it has become very popular as the back-end database for many web sites with simple demands. There is a tradeoff for MySQL's lean nature: it is missing some advanced features that make it not quite fully ANSI SQL-92 compatible. It is completely lacking transaction support (commit and rollback) as well as fine-level locking. I do not recommend trying to use MySQL for Enterprise Java Beans which we will cover last in this series. For that we will use PostgreSQL.
PostgreSQL Installation and Access via JDBC (5/12/2001: notes,outline): PostgreSQL is another Open Source relational database (SQL) server. It has a long lineage and has been under development for a very long time. There's been ample opportunity for the developers to fine-tune its performance, making it a very full-featured competitor to other commercial databases. We will use PostgreSQL to explore Enterprise Java Beans.
Servlets and JSP using Jakarta Tomcat: Java Servlets and Java Server Pages (JSP) are one of the few standardized methods for creating dynamic web sites. A spin-off Apache project, Jakarta Tomcat acts as the reference platform for the Servlet/JSP portion of Sun's Java 2 Enterprise Edition. This is no trivial matter! I know of at least one Fortune 50 company that has chosen Tomcat as its official JSP platform. Creating "Web Applications" with Tomcat is a little more involved than making a simple web page under Apache. This article will cover the basics for getting a simple web application up and running.
Using Databases with Tomcat: More often than not, dynamic web applications use databases to store and retrieve information. When programming in Java, one access a database with the JDBC API. This article will walk you through the simplest possible exercises to access MySQL and PostgreSQL with a Servlet or Java Server Page. Some advanced topics of connection pooling will be discussed, and we will investigate methods of configuring Tomcat itself to make database connections available.
Improved JSP Design using Taglibs in Tomcat: There are many ways to write web applications. Unfortunately, many of the more intuitive approaches lead to very bad design flaws, and in some cases serious performance problems. This article will discuss the philosophy of separating content, layout and implementation. In short, I will attempt to convince you to move as much Java code out of the web page and into "taglibs". This is simply the right way of doing things and the sooner you can train yourself to adopt good habits, the better off you'll be.
XML Web Development using Cocoon: Touted as the eventual replacement of HTML, XML has remained to most people little more than a buzzword with unrealized promise of revolutionizing computing. I will attempt to demystify this computer "language" and show a simple example of how to design your web sites in XML. While most browsers are still unable to handle XML, Cocoon offers a nice service of translating XML web pages "on the fly" into browser-friendly HTML.
Advanced XML using XSP and Taglibs in Cocoon: The Cocoon developers have drafted a standards proposal for XSP (basically, the XML equivalent to JSP) to create dynamic XML content. We will look at simple examples of XSP, including the integration of database access, LDAP queries, and more!
Enterprise Java Beans with JBoss: Time to bring out the big guns! There are very few people in the world who know how to write EJB's, and they can command some serious money. This article will attempt to explain what EJB's are, and show a very simple example or two. The developers of JBoss (and Open Source implementation) have figured out how to integrate JBoss with Tomcat so that they can run under the same Java Virtual Machine (JVM). I am working on a OS X Package Installer for Tomcat+JBoss+Cocoon.

As profound as modern Open Source software is in its completeness and sophistication, equally amazing is the community that supports it. It's ironic that corporate CIO's are afraid to embrace Open Source software because of it's lack of central "accountability". (In other words, when things go wrong, they want a phone number they can call.) Sadly, support for many commercial applications is expensive and/or poor in quality. On the other hand, there are ample stories about people who monitor mailing lists and will fix a software bug and submit a "quick fix" patch in a matter of hours.

When exploring a new technology, there are some simple steps that will get you on the fast-track to functionality. One important step is subscribing to the relevant mailing list, finding the FAQ if one is available, reading several days or weeks worth of e-mails to get an idea of the what support is being offered (and to make sure you don't ask a question that someone already answered the day before) and to participate wherever you can.

These mailing lists are where you can go to find the answers to your specific problems. I am happy to receive e-mail that discusses the material in my articles (what's confusing, what you might disagree with, what's missing, etc.) but I'm simply going to have to ignore most "technical support" types of questions.

One additional disclaimer: all modern software requires tuning before it gets deployed in a real production environment. This tuning impacts two very important issues: performance and security. Any package installer that I provide is designed to make it easy for the beginner to start developing quickly and easily. Some of my configuration choices were made for convenience at the cost of security. One of the responsibilities of being a web developer is the careful examination of every line of every configuration file. Consider yourself warned!

And now, let's have some fun and explore the world of advanced web design!