Echo Web Framework

Hello all,

The big news in the past couple months of Echo3 development has been the maturing of the client-side version of the framework. This was accomplished largely by creating the Client-Side JavaScript Demo App, which currently stands just shy of about 5,000 lines of JavaScript code (note that line counts tend to be significantly lower for JS apps compared to server apps). The development of this application served three purposes: The first was nothing more than to show off what the framework can do and serve as a marketing tool. The second was to provide a proper example application. The third and arguably most important was to test and refine the client-side framework by writing a reasonably complex application with it.

Content not yet available.

Echo3 Extras provides a collection of additional user interface components for the Echo3 framework. This project is currently under development and should be considered beta-quality software.

Current components provided by the Extras library include:

NextApp-maintained Echo3 Add-Ons

• Echo3 Extras: Collection of additional useful Echo3 components.
• File Transfer Library:Library providing components for uploading and downloading files between client and server.

Echo3 includes a tool to convert stylesheets from the Echo2 format to the Echo3 format. This tool is provided in the Echo3 distribution in a JAR file located at Util/Echo3_StyleConverter.jar.

To convert a stylesheet, invoke the following command from a shell / command prompt:

java -jar Util/Echo3_StyleSheetConverter.jar [inputfile] [outputfile]

Replace [inputfile] and [outputfile] with the location of the Echo2 stylesheet and desired output location of the Echo3 stylesheet respectively.

Echo is divided into two primary modules the "Application Framework" and "Web Container". The "Application Framework" module defines the components, properties, and events that an end-developer uses to create an application. The "Web Container" serves as a back-end to render the application to the client.

General Application Framework Changes

With Echo3, the application framework receives very minor changes compared with Echo2, and thus porting code that uses the application framework is fairly trivial.

Package Name Change

General Questsions

Q: How do I start using and learning Echo?
A: Read the Developer's Guide.

Q: What is Ajax?

The following provides an overview of some major new features present in Echo3 (compared to Echo2). This list is not yet complete.

Server-Side Java Features

• Component Framework Backward Compatibility: The Echo3 and Echo3Extras Java libraries are MOSTLY backward compatible with Echo2. Some porting work is required: the most notable issue is that the base package name has been changed form "nextapp.echo2" to "nextapp.echo". The first step in porting is thus a global search-and-replace. XML Stylesheets must be translated to a new format (a translator is provided). Additionally, EchoStudio3 provides a complete project translation utility. The only significant work in porting is with custom components which render their own HTML and JavaScript: such components must be ported to a new API (which is far more straightforward and automated than the Echo2 equivalent).