Starting From Scratch

Building a good WO application is not just about nice data models and fast algorithms. Making the right decisions from the start and taking advantage of code written by the community is also very important. Here we'll talk about some stuff that you should care about from the start.

Use WONDER

Why?

WONDER is a huge set of frameworks that fix and extend WebObjects in many, many ways. For more than five years, Apple barely updated WebObjects, and that shows. There are bugs that date from 2003 still unfixed, there are almost no new features. WebObjects 5.4 is a nice release that includes a lot of fixes and some new functionality, but it was only released in late 2007, with Leopard. During all that time, though, the community hasn't been sleeping. The WONDER team wrote thousands of lines of code, and made them available for the rest of us.

The WONDER framework most people use is ERExtensions. This framework is probably the biggest in WONDER, and contains a lot of great functionality you don't want to live without. Some of it's features are:

• XHTML generation. Although WebObjects 5.4 finally provides XHTML compliant code generation, WONDER was the only way to achieve that in previous WebObjects versions. I mention this feature first because it actually was the feature that made my start using WONDER in first place.

• Automatic EOEditingContext locking. This feature is huge. We'll talk about locking a lot in later sections, but trust me, you'll want WONDER to handle the locking for you. No more unlocked contexts to be corrupted while you edit them, and no more deadlocks and locked contexts lying around.

• Collections re-implementation supporting Java Generics. This means that you may create an NSArray, NSDictionary or any other "NS collection" typed to a class or interface. I don't actually like this feature, because I'm a LISP lover and I see this as unnecessary constraints. Anyway, I mention this because I admit it may improve the code quality in some ways, and because WONDER implementation is, in some ways, better than Apple's (Apple delivered generics support for collections in 5.4).

• COUNT SQL query generation. This is a very, very useful feature, at least for me. There are many times when you just want to know how many objects are selected by a query, but you don't want the objects themselves, specially because we may be talking about tens of thousands, or more. Think something like Amazon querying its system for the number of books sold this month. The query results would be huge and unpractical to manage in memory and time, and an unacceptable overhead if all you want is the count. WONDER provides a very easy way to do COUNT (and COUNT UNIQUE) queries.

• Extra qualifiers. Sometimes WO qualifiers are simply not enough. WONDER provides some handy qualifiers. Some of them are buggy and may not work, it's not one of the best quality WONDER features, but at least it's there, and it's open source, so you can fix any bugs you find.

There are many, many more nice things about EXExtentions framework. You would be really bored if I described only 10% of them. Besides ERExtentions, there are also a number of cool extra frameworks in WONDER. Here are some of them:

• Ajax Framework - provides a really easy way to add Ajax calls to your application. Ajax Framework integrates Ajax in the WebObjects Request-Response loop in a very intelligent way. You program all of the Ajax stuff as you program normal component actions. An action method is called, you do whatever you want, and return a component (usually null). The defined block of the page is updated. No page reload, the user is happy, and you are more than happy because you actually had to do nothing (well, almost). We'll look at Ajax Framework later.

• ERJavaMail - useful framework for managing email.

• ERPrototypes - A collection of data model prototypes for popular databases. You may use this framework or create your own prototypes, but do use prototypes. If you are lost, don't worry, we'll look at this later.

• ExcelGenerator - A POI wrapper framework for generating Excel documents, a very useful feature in many web applications.

• ERPlot - A JFreeChart wrapper for generating nice-looking charts on your web application.

By now, you must be thinking why would you make the learning curve even worse by learning WONDER and WO at the same time. After all, it's a lot of frameworks, a lot of information and, unfortunately, not a lot of documentation.

The point is: using WONDER will actually make it easier to learn WebObjects. WONDER fixes a lot of bugs and provides a lot of easier solutions, like EOEditingContext automatically locking, that would otherwise drive you mad if you use pure WO. So, the best option for you to learn WO easily is to use WONDER, at least ERExtensions. Although it seems you are complicating your life, you are really making it (a little) easier.