WebObjects Matt Aguirre Lally Singh

What Is It? A Java based development platform specifically designed for database-backed web applications.

What Does It Have?  Scalability: built in load balancing among a dynamically configurable set of servers  Industry standards support: JSP/J2EE/JNDI support built in  Multiple client type support: Web Browser, Java Client Application, XML, SMIL, WAP…  Easy extensibility: add new web components for immediate reuse.

Architectural Overview

Architecture In Depth

Web Components  Three Parts: HTML file Bindings file Java code  Embeddable within themselves: follows the Composite design pattern  Embeddable within JSP pages  Communicate to each other & Enterprise Objects (EOs) through Key-Value coding

Example Web Component  A simple form containing two items: a textbox and a submit button  User hits ‘Submit’ and the name is shown in System.out.  Not very useful

The HTML Untitled Sample Form Name:

The Bindings Form1: WOForm { } SubmitButton1: WOSubmitButton { action = submit; } TextField1: WOTextField { value = name; }

The Java File public class Main extends WOComponent { protected String name; public Main(WOContext context) { super(context); name = new String(); } public WOComponent submit() { System.out.println("name="+name); return null; // default - means we go back to same page }

What Happens?  When the page is requested, the value for name is taken from the Component’s instance via Key-Value Coding  The page is displayed to the user  The user types in something into the textbox  The user hits submit  WO updates the value of name with what the user put in the textbox  WO then calls Main ’s submit () method  submit () prints out the string the user typed in

Key Value Coding  A method to access data in classes without relying on their interfaces  Implemented through the KeyValueCoding Java interface  The default implementation scans through reflection. Ex: to set the key foo, the following will be checked in order: 1. setFoo()4. _isFoo 2. _setFoo()5. foo 3. _foo6. isFoo