O’Reilly EmergingTechnology Conference

Oliver SteeleChief Software Architect

Laszlo Systems, Inc.

April 23, 2003

Announcement

• BOF: Are There Riches in Rich Internet Applications?“This BOF will provide a forum to discuss the

economics of software and services focused on the user experience: how the industry obsession with servers will interact with the emerging emphasis on application front ends.”

• Winchester (this room) 6-7pm

• Pizza

LZX Goal: RIA Development

• LZX = XML + JavaScript– DHTML with different tags– Tags to declare views, layouts, data, animation– Leverages existing skills and capabilities

• Developer sees DHTML• Deployer sees J2EE servlet• Browser sees SWF file• User sees a RIA

• HTML is designed for static page publicationpage = content + structure + formatHTML = text + markup + style

• LZX is designed for rich internet applicationsRIA = data + logic + presentationLZX = XML + JavaScript + components

Thin Internet Application

Dynamic Internet Application

Rich Internet Application

Ingredients of a RIA

Ingredients of a RIA Platform

Features

• Model– Data (XML)– Data Requests (HTTP)– Data Binding (XPath; DOM)

• View– View Components (XML tags)– View Hierarchies (XML structure)– Animation (SMIL-like)– Constraints (JavaScript expressions)

• Control– Scripting (JavaScript)– Events (CSS Event names)

• Modularity and Extensibility– Classes (XML tags)– Includes (XInclude)– Component Libraries (tags + includes)

Pizza

LZX Feature Walkthrough

Desktop Application Model (MVC)

Supporting RIA Development

• Best Development Practices– Modularity– Extensibility– Separation of concerns (MVC)

• Team Development Practices– Text-based– Collaboration– Media import

• Productivity– Declarative– Standards-based– Low boilerplate

Architecture of a RIA

• Model– Data

• View– Media– Animation– Components

• Control– User interaction– Business logic– Server transactions

LZX Ingredients

• XML– View hierarchy– Data

• JavaScript– Program logic and behavior– “Back door”

• Other Technologies– XPath for binding views to data– HTTP for data and media queries

Looking Back: HTML

• Simple applications are simple

• Complex applications are feasible

• Supports collaboration between developers and designers

The domain is thePresentation of static documents.

Looking Forward: RIA Development

• Simple applications should be simple

• Complex applications should be feasible

• Support collaboration between developers and designers

The domain is thepresentation of rich interactivetransactional web-deployed applications.