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Volume Number: 17 (2001)
Issue Number: 09
Column Tag: Beginning WebObjects 5
Part 1 - Presenting WebObjects 5
by Emmanuel Proulx
Introduction & Installation
Preface
This new column deals with WebObjects 5. It is meant to be easy and fun to read. This column talks about developing a Web application using WebObjects 5, in Java. Originally, this column was a book, with hundreds of pages. It has been cut down a lot to accommodate space restrictions.
Those interested in learning to build Web applications using WebObjects 5 should read this column. The only prerequisite is being Java programmers of at least intermediate level.
Other knowledge is not necessary, although understanding HTML basics can help tremendously because WebObjects borrows many characteristics from this language. If you don't know HTML at all but you still want to learn WebObjects, just skip the paragraphs that talk about HTML. For your convenience, these are usually marked with the symbol <HTML>. You won't get into any trouble, but you will not understand how WebObjects works behind the scene.
The same thing goes with databases. While knowing databases and SQL isn't necessary, you have to have basic knowledge if you're going to read the sections about databases. Database software is necessary if you're going to try out WebObjects' database features. I tried to keep all of the database interfacing and programming contents in separate sections for convenience.
Note that someone who masters Java programming, client/server design, HTML and Web Design as well as databases and SQL will be able to learn WebObjects radically faster.
What Is WebObjects?
I started this new job and the job description was "Java Developer". I was expecting to use one of these Java IDEs like Visual Café or Visual Age. My new boss said, "No, here we use WebObjects". I had heard about that tool, but I didn't know it was a Java IDE. It wasn't.
WebObjects is an environment for developing interactive Web Sites. The Java language is being used to implement Server-side behavior; the client side is mostly HTML, not necessarily Java Applets or even JavaScript for that matter.
WebObjects is much more than that. If also falls into the Application Server category. What is that? In the past, a "Server" would consist of just a Database. Nowadays a Server can also handle distributed transactions, multi-tier architecture, load-balancing, business logic, Enterprise JavaBeans, and other concepts and technologies involving more advanced server-side intelligence. An environment that helps with the development and deployment of such complex Servers is called an Application Server.
WO consists of multiple tools that are tightly integrated.
- Project Builder: lets you browse the source code and manage the project.
- WebObjects Builder: lets you assemble a Web Page.
- Enterprise Object Modeler: lets you connect your Web Application to a database.
- Interface Builder: lets you create Java applications and applets that connect to the WebObjects server for executing business logic and database access.
- Direct To Web: a wizard that creates a complete database-driven customizable Web application.
- Direct To Java Client: a wizard that creates a complete database-driven customizable Java program or applet.
- Monitor: a remote task monitoring and performance analysis utility.
Other smaller utilities like a ‘Diff' utility, debugging tools, etc.
Other modules are included, yet they are not visible:
- Web Server Adaptor: plugs into your Web Server to connect it to WebObjects.
- JDBC Database Adaptor: connects WebObjects to a database driver.
- The frameworks, which are powerful programming libraries. They support the whole WebObjects system. We refer to them as the Foundation, WebObjects and Enterprise Object Frameworks. The preceding tools make use of the Frameworks, and even generate some code that uses them.
How do these tools work with each other? The Figure 1 illustrates their interactions.
Figure 1. Interactions between the tools
In a typical WebObjects application, the focus is the project file, which points to the different components of the application. The Project Builder manages this file. Then, to create the Web Components (Web pages), you usually run the WebObjects Builder program. When a component makes use of a database, you have to use a model to link the tables of the database to your system's objects. This model is created using the EO Modeler. To let a user connect to your site, you need a Web Server containing the WebObjects Adaptor. There's more on each of these parts later on.
Lastly, WebObjects also is an IDE for developing Cocoa and Carbon applications, but this column deals only with Web applications.
Installation Information
First you must know that there are two distinct packages that can be installed with WebObjects 5. Each has its own specific use and list of installed components.
- Developer edition: Contains all the graphical tools and libraries. Used for the development environment. At the time this was written, only the Mac OS X would support the Developer Edition.
- Deployment edition: contains only the deployment tools and the run-time libraries. Used for the deployment environment. Can be installed on top of the Developer edition on Mac OS X. The Deployment Edition is available for a variety of platforms.
This column generally talks about the Developer edition. The Deployment edition will be covered in a separate article.
To develop with WebObjects Developer Edition, you need a Mac OS X environment with at least 128 megabytes of RAM and 600 megabytes of hard disk space. That said, remember this golden rule: you never have enough RAM and hard disk space!
Once you're done with your development, you can deploy your application on either Mac OS X, Windows 2000, or Solaris.
You will also need a supported Web server. On the Mac OS X, the default server is Apache, and works great.
If speed doesn't matter that much to you, you can get any Web Server with CGI capability. Else, you have to get a Web Server compatible with either the NSAPI or WAI standards (Netscape's Web Servers), ISAPI (Microsoft's Web Servers) or Apache. Of course, select a Web Server that works on your deployment platform.
If you need to access a database, you want to use one that has a JDBC 2.0 driver. WebObjects comes bundled with an evaluation version of OpenBase. But on deployment platforms you may want to go for an industrial-strength database, like Oracle, Informix, Sybase, DB/2, etc. You can also connect to any ODBC-compliant database on Windows using the ODBC/JDBC bridge, but that would make things slower.
NOTE: Not many database products are available on Mac OS X, so you may want to purchase a complete version of OpenBase (www.openbase.com).
Installation
Pre-Installation Steps
It is very important to install your Web Server before you install WebObjects.
NOTE: if you already installed WebObjects and you want to install a Web Server afterward, the only issue is with the "cgi-bin" folder. WebObjects has already copied its required executables in a temporary "cgi-bin" folder. After setting up your Web Server, you will have to copy these executables in the new Web Server's "cgi-bin" folder (you will have to make one if there is none).
Also, it doesn't hurt to install your database software at this point if you don't have one already.
On Mac OS X, both Apache and OpenBase are installed by default.
To install WebObjects on any platform, you need to log on as the Administrator (or root) user. If you don't have Administrator (or root) access rights, it won't work at all.
On Mac OS X, you have to first enable the root user (which is blocked by default) and then to log on as the root user. To enable the root user, open folder /Applications/Utilities, and double-click on NetInfo Manager. Once NetInfo Manager is running, open menu Domain | Security | Enable Root User. You will be asked to enter a password for the root user. Now log off and log on again using ‘root' as the user name, and the password you set previously. You are now logged as the root user and ready to install. After the installation is finished, you may disable the root user by running NetInfo Manager again.
Installation Steps
Insert your WebObjects CD in your CD-ROM drive. Double-click on the new icon that shows up in the desktop. Now double-click on the icon marked WebObjects_X_Developer.mpkg. This will call the installation program. Then, follow the instructions in the wizard-like window.
The following notes are meant to help you along the way. Read them before starting the install:
- The serial number is usually located on a sticker on the CD envelope.
- Be sure to read carefully the License Agreement for the next two hours. ;-)
- Most people should choose a Typical Install. The Typical Install includes everything except the following (generally unimportant) items:
- The Japanese language support
- The source code
- At one point, the WebObjects installation program could ask you for your Web Server's "cgi-bin" folder and its "docs" folder. Check them out and write them down before you start the install.
- This process takes a very long time - be patient.
- You will need to restart your computer at the end of the install, so it's a good idea to save your data and close all programs before even starting it.
Patches
I recommend that you install the latest patches for all of these (if you use them):
- WebObjects itself
- The operating system
- The Web server
- Your database software
For the Mac OS X, updating to the latest patch is very easy. You can get all the patches by going to the System Preferences panel, in the category Software Update. You will find there a button "Update Now". Clicking on it will check all software versions against an online database of patches. It will propose updates when they are available. I suggest you apply all of them. At the time this article was written, there was one patch available, which fixes many bugs. Install it.
On other platforms, updating to the latest patch may require that you visit each vendor's Web site and check for patches there. That's it — you are now ready to enjoy your development environment.
I didn't cover the deployment installation here because it is a complex topic that deserves its own article.
The Find-A-Luv example
I designed this column to have a good balance of theory and examples. I took good care of the theory, but I didn't want to make tiny useless examples and toy-code I had seen too often. Also, I didn't want to just show how to use the wizards of WebObjects and leave you alone with the customization. I needed a real Web Application and I wanted to develop it from scratch, not using just the wizards...
So throughout this column, I will be developing, as the main example, always the same Web Application. It features a Web Site for an imaginary dating services company. This company's promise is to help find nothing less than the client's soul mate. But be forewarned: if you're looking for your soul mate, this column will not help you.
We will start small and we'll expand this example as we go along.
Web Development Alternatives
WebObjects is not alone. There's a lot of competition out there. Many tools offer interactive Web Site/Server-side processing and Application Server solutions. Let's digest a few of the most popular ones.
Competing Interactive Web Site Solutions
The first ever solution for that is the CGI (common gateway interface). This is the most primitive solution. CGI is not a product; it's a feature of your Web Server that lets you insert your own program in you Web Site. That program can receive the user's input, and outputs a new Web Page based on it. The main disadvantage of the CGI is that the HTML code and database access are encapsulated into the source code; this is not pretty nor is it easy to develop. The main advantage is that you don't have to buy software to use CGI programs since it's already in your Web Server. Just use any computer language and you're on your way.
Sun Microsystems' Java Servlets are based on the same idea as CGIs, except they are written in Java and use their own module (called Servlet Runner program) that adds on to the Web Server. They have similar advantages and disadvantages as CGIs except for the fact that certain Web Servers don't support Servlets natively. Or if they do, their quality leaves a lot to be desired. This is the reason why commercial third party Servlet Runner programs (like Allaire's JRun) are available.
Allaire's ColdFusion is a commercial product that lets you write HTML "templates". That is, you write your HTML like you would normally do for your Web Page, and then you add in the same file the logic that makes the page interactive. You can even link your page to the database in only a few steps. The advantage is that you can use an HTML graphical editor for most of the work, and then add the logic afterward. ColdFusion is easy to use and produces results fast (just like HTML does). The main problem with ColdFusion is that it's not a real computer language; you can quickly arrive at the limit of what it can do.
Microsoft's ASP (Active Server Pages) also relies on "templates". But the logic is coded with Visual Basic. The main advantage is, like ColdFusion, fast development and tools that let you create pages easily. The disadvantage is that ASP is not portable: you can only use it on Microsoft's Web Servers.
Sun Microsystems' JSP (Java Server Pages) is an important player. JSP is based on the same idea as ASP, but the logic is coded in Java.
Here's a grid that summarizes the different characteristics of these solutions:
| Alternatives | CGI | Servlets | ColdFusion |
| Characteristics | |||
| Comes with your | Yes | Some | No |
| Web Server | |||
| Uses templates | No | No | Yes |
| Logic and HTML in | No, HTML | No, HTML | No, code |
| separate files | in code | in ccde | in HTML |
| Flexibility of a | Yes | Yes | No |
| real language | |||
| Supports most | YES | Yes, with | Yes |
| Web Servers | Servlet | ||
| Runner | |||
| program | |||
| Uses Java | No | Yes | No |
| Alternatives | ASP/JSP | WebObjects | |
| Characteristics | |||
| Comes with your Web Server | Some | No | |
| Uses Templates | Yes | Yes | |
| Logic and HTML in separate files | No, code in HTML | Yes | |
| Flexibility of a real language | Yes | Yes | |
| Supports most Web Servers | NO | Yes | |
| Uses Java | JSP only | Yes |
Competing Application Servers
When Sybase wanted to issue an application server, they decided not to reinvent the wheel. They put together a set of existing tools then integrated them. Their Enterprise Application Server (or EAServer) is composed of Sybase's Jaguar CTS (application server) and PowerDynamo (Web server). EAServer is integrated with development tools like PowerBuilder and PowerJ, but these come separately.
IBM's application server is called simply WebSphere Application Server (Standard Edition). It features Servlets and JSP, a Web Server, and integration with Visual Age for Java and WebSphere Studio — sold separately. The Advanced and Enterprise editions offer more features, like EJB, better performance, security and other advanced features.
The Oracle Application Server provides a basic set of features; Web Server (with Servlet and JSP support), EJB, a stable and scaleable environment for deploying Web applications. It is also integrated with Oracle's IDEs, Oracle Developer and JDeveloper.
BEA's WebLogic Server is an application servers that follows the J2EE standard to the letter. It features also Servlets and JSP for the dynamic HTML part, integrated with the most popular third-party IDEs. EJB, Java 2 Enterprise Edition and the latest standards are supported.
Here's a grid that summarizes the different characteristics of these solutions:
| Alternatives Characteristics | |||||
| Sybase | IBM | BEA | |||
| EAServer | WebSphere | WebLogicServer | |||
| Uses J2EE/EJB | Yes | Yes | Yes | ||
| Works on Mac | No | No | No | ||
| Comes with an IDE and tools | No (separate) | No (separate) | No | ||
| Does distributed | Yes | Advanced | Yes | ||
| transactions, | Edition only | ||||
| monitoring and | |||||
| load balancing. |
| Alternatives | |||||
| Characteristics | Oracle | WebObjects | |||
| Application | |||||
| Server | |||||
| Uses J2EE/EJB | Yes | No | |||
| Works on Mac | No | Yes | |||
| Comes with an IDE and Tools | No (separate) | Yes | |||
| Does distributed transactions, monitoring and load balancing | Yes | Yes |
As I am writing this book, there are countless different application server packages on the market. I will not cover them all, but I am convinced that only WebObjects covers such a wide variety of tools and features. But in general, I have noticed that most of the other application servers are just a bunch of distinct tools put together. Many of these products are tied to a single Web server or database. On the other hand, WebObjects has fully integrated tools that work together as a whole and leverages whatever tools (Web Server, database) you already have. Its programming libraries and database tools are jewels and no other vendor offers similar tools. While WebObjects does not follow the J2EE specification, its proprietary nature enables Apple to provide easy-to-use RAD tools and many "value-added" features. Furthermore, WebObjects is the only application server available on the Mac OS X.
Emmanuel Proulx is a Course Writer, Author and Web Developer, working in the domain of Java Application Servers. He can be reached at emmanuelp@theglobe.com.
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