WebObjects - Core Frameworks

Core Frameworks

A WebObjects application is essentially a server-side executable, created by combining prebuilt application framework objects with the developer's own custom code. WebObjects' frameworks can be broken down into three core parts:

• The WebObjects Framework (WOF) is at the highest level of the system. It is responsible for the application's user interface and state management. It uses a template-based approach to take that object graph and turn it into HTML, or other tag-based information display standards, such as XML or SMIL. It provides an environment where you can use and create reusable components. Components are chunks of presentation (HTML) and functionality (Java code) often with a parameter list to enhance reusability. WebObjects Builder is used to create the HTML-templates and creates the .wod-file linking, for instance, a Java String object to interface objects like an input field in a web form.
• The Enterprise Objects Framework (EOF) is, perhaps, the hallmark feature of WebObjects. EOF communicates with relational databases and turns database rows into an object graph. Using EOModeler the developer can create an abstraction of the database in the forms of Java objects. In order to access or insert information into the database the developer simply accesses the Java Enterprise Objects (EOs) from their business logic. After that EOF manages the Enterprise Objects and automatically creates the required SQL-code to commit the changes to the database.
• Java Foundation. Both Enterprise Objects and WebObjects rest on the aptly named Java Foundation classes. This framework contains the fundamental data structure implementations and utilities used throughout the rest of WebObjects. Examples include basic value and collection classes, such as arrays, dictionaries (objects that contain key-value pairs) and formatting classes. Java Foundation is similar to the Foundation framework contained in Apple's Cocoa API for Mac OS X desktop applications, however Java Foundation is written in Pure Java as opposed to Cocoa's Objective-C (with its Java bridge runtime wrapper). Foundation classes are prefixed with the letters "NS" (a reference to their NeXTStep OS heritage). Since the transition of WebObjects to Java in 2000, the functionality of many of Apple's Java Foundation classes is replicated in the Sun's own JDK. However, they persist largely for reasons of backwards-compatibility and developers are free to use whichever frameworks they prefer.