Sams Teach Yourself Linux in 24 Hours is a tutorial aimed at making the Linux beginner more effective and productive users of the operating system. Most books in this category are more of a general reference in nature and are designed to cover Linux in general. Well, every Linux distribution is different - file locations can change, commands can be a little different, etc. This means the readers of those books may not find answers specific to their installation. This book will use the effective Sams Teach Yourself format to instruct the reader how to: install the operating system, configure their hardware, and effectively use the tools that come with the Red Hat distribution included on the CD-ROM.

• Learn how to install Red Hat Linux by walking through an easy to follow hardware configuration
• Understand how to use Linux commands, configure your network and servers and manage users of your system
• Discover the power of X(TM) Windows
• The CD-ROM delivers Red Hat Linux V5.0--a $49.95 value-- complete with source code

Introduction

The journey of a software developer is an interesting one. It starts with taking things apart and inspecting the isolated components to try to understand the whole system. Next, you start poking at and hacking the system in an attempt to manipulate its behavior. This is how you learn—by hacking.

You follow that general pattern for some time until you reach a point of confidence where you can build your own systems from scratch. You might roll your own content management system, for example, deploy it on multiple sites, and think you’re changing the world.

But there comes a critical point, and it usually happens when you realize that the maintenance of your system starts to take up more time than building the features, when you wish that you knew back when you started writing the system what you know now. You begin to see other systems emerge that can do what your system can do and more. There’s a community filled with people who are working together to improve the software, and you realize that they are, for the most part, smarter than you. And even more, the software is free.

This is what happened to me, and maybe even you, upon discovering Drupal. It’s a common journey with a happy ending—hundreds of developers working together on one simultaneous project. You make friends; you make code; and you are still recognized for your contributions just as you were when you were flying solo.

This book was written for three levels of understanding. First and most importantly, there are pretty pictures in the form of diagrams and flowcharts; those looking for the big picture of how Drupal works will find them quite useful. At the middle level are code snippets and example modules. This is the hands-on layer, where you get your hands dirty and dig in. I encourage you to install Drupal, work along with the examples (preferably with a good debugger) as you go through the book, and get comfortable with Drupal.

The last layer is the book as a whole: the observations, tips, and explanations between the code and pictures. This provides the glue between the other layers. If you’re new to Drupal, I suggest reading this book in order, as chapters are prerequisites for those that follow.

Lastly, you can download this book’s code examples as well as the flowcharts and diagrams from http://drupalbook.com or http://www.apress.com.

Good luck and welcome to the Drupal community!

Introduction

So there I was, just minding my own business, when along came a publisher asking me if I’d be interested in writing a book on JavaScript. It seemed like a good thing to do at the time, so I said yes.

I’m just kidding. No one asked me, I just showed up one day on the doorstep of Apress with a manuscript and some puppy-dog eyes. I’m just kidding again.

Seriously though, JavaScript is one of those kids we all knew when we were young who start out really ugly, but whom everyone wants as their beautiful date to the prom years later. Then they go on to Yale, become a district attorney, and suddenly everyone realizes that they really want to be with that person. Fortunately, unlike the DA, JavaScript doesn’t involve crimes and misdemeanors, since you know you don’t have a chance any other way with the DA! JavaScript has quickly become one of the most important topics in web development, one that any self-respecting web developer can’t do without. With the advent of Ajax, which I’ll talk about in this book, JavaScript has very quickly gone from something that can enhance a web site a little to something used to build very serious, professional-quality applications. It’s no longer a peripheral player; it’s a main focus nowadays.

There are plenty of books on JavaScript and plenty of how-to articles strewn across the intrawebs, any of which can be of great help to you. Far harder to come by though are real, substantial examples. Oh, you can get a lot of simplistic, artificial examples to be sure, but it’s more difficult to find full-blown, real-world applications that you can examine. Many developers learn best by tearing apart code, messing around with it a bit, and generally getting their hands dirty with real, working bits. That’s why I wrote this book: to fill that gap.

In this book, you will find two chapters on some general JavaScript topics, including a brief history of JavaScript, good coding habits, debugging techniques, tools, and more. From then on, it’s ten chapters of nothing but projects! Each chapter will present a different application, explain its inner workings, and offer some suggested exercises you can do to sharpen your skills and further your learning. The projects run the gamut from generally useful (an extensible calculator) to current ideas (a mashup) to just plain fun (a JavaScript game).

In the process, you will learn about a wide variety of topics, including debugging techniques, various JavaScript libraries, and a few somewhat unique and useful approaches to coding. I believe you will also find this to be an entertaining book, and in fact, one of the exercises I suggest from the beginning is to try to pick out all the pop-culture references scattered all over the place (try to place them without looking at the footnotes that accompany most, but not all!). I tried to make this book like an episode of Gilmore Girls in that regard (and if you aren’t familiar with the show, there’s your first pop-culture reference!).

So, enough babbling (for the time being anyway). You know what’s coming, so let’s stop dropping hints about numbers, Dharma, and bizarre connections between characters (popculture reference number 2!), and get on with the good stuff. Let’s get on with the show!

The Web is everywhere, reaching into the homes of everybody with a computer and a phone line. More and more of us have our computers on all the time, continuously receiving and sending messages and email, frequently looking for information, for pictures, for music.

I do most of my Christmas and birthday shopping online; most of our gifts for weddings and graduations are purchased online and shipped— gift-wrapped—directly to the recipients.

Rumors spread like wildfire on the Web. Sentimental stories (we call them “web weepers”) are passed along, jerking tears whether they’re true or not. Financial scams, ads for body enhancements, and political fund-raisers pump through the system.

Real news comes from volunteer reporters (bloggers, they’re called, whether they’re actually writing blogs or not), forcing the traditional news media to deal with stories they would have preferred to ignore. And those political fund-raisers have changed the shape of American elections, allowing some candidates to bypass the traditional fat-cat and PAC fund-raising methods.

All of this is so pervasive that it feels perfectly natural. It’s easy to forget how short a time it has been this way.

Twenty-five years ago, in 1983, I moved to Greensboro, North Carolina, to take a job as book editor for Compute!, a magazine that covered all the major home computers: Commodore 64 and VIC, Atari 400 and 800, TRS-80, Apple, and a few others that popped up and faded away.

While I worked there—for only nine months—Apple launched their Lisa computer, which in many ways resembled the later Macintosh, and IBM announced the PC.

In other words, the two dominant personal computers did not yet exist. Meanwhile, the Internet, while it existed, was restricted to academics and Defense Department wonks—civilians like me need not apply.

What This Book Is About

This book will demonstrate the use of freely available Java Open Source (JOS) development frameworks for building and deploying applications. Specifically, we will focus on the JOS development frameworks available from the Apache Software Foundation (http://apache.org) as well as its Jakarta group (http://jakarta.apache.org).

While most books are heavy on explanation and light on actual code demonstration, this book emphasizes approachable code examples. The authors of this book want to provide a roadmap of JOS development tools to build your applications. Our intent in this book is not to present each of the frameworks in minute detail. Frankly, many of the development frameworks presented in this book could have entire books written about them.

This book will build a simple application using the following Apache technologies, except for XDoclet:

Struts Web Development framework: A Model-View-Controller–based development framework that enables developers to quickly assemble applications in a pluggable and extensible manner. This book will highlight some of the more exciting pieces of the Struts 1.2 framework. These pieces are described next.

Tiles: A new user interface framework that allows a development team to “componentize” a screen into granular pieces of code that can be easily built and updated. Dynamic ActionForms and Validator framework: A new set of tools for alleviating many of the more monotonous tasks of writing web-based data collection screens.

Lucene: A powerful indexing and search tool that can be used to implement a search engine for any web-based application.

Jakarta Velocity: A templating framework that allows a development team to easily build “skinnable” applications, whose “look and feel” can be easily modified and changed. ObjectRelationalBridge (OJB): An object/relational mapping tool that significantly simplifies the development of data access code against a relational database. ObjectRelationalBridge can literally allow a development team to build an entire application without ever having to write a single line of JDBC code.

XDoclet: A metatag-based, code-generation tool that eliminates the need for a developer to support the usual plethora of J2EE (web.xml, ejb-jar.xml, etc.) and Struts (struts-config.xml, validation.xml, etc.) configuration files. It is important to note that XDoclet is not an Apache technology. However, XDoclet has strong support for Struts and has been included as a topic of discussion for this book.

Ant: An industry-accepted Java build utility that allows you to create sophisticated application and deployment scripts.

In addition, this book includes a quick introduction and overview of Asynchronous JavaScript and XML (Ajax). Ajax is a technology that addresses a very common problem in web application development. Let me introduce this with the help of an example