Echo Web Framework

To ensure Echo3 applications are accessible by a broad array of users and devices, the platform has been designed to work well regardless of a user's chosen font size. Some users or environments may need text to be rendered in larger-than-normal sizes, and Echo works to avoid burdening the developer with the issues that can arise from such arbitrary sized fonts. The most notable features include the capability to specify font-relative dimensions for components and automatically position and scale container components based on the size of their rendered content. JavaScript/HTML component developers can also take advantage of cross browser content-measuring APIs and the multiple-phase rendering architecture of Echo3.

Echo3 Chart provides support for rendering charts using JFreeChart from within a server-side Echo3 application. All of the heavy-lifting is done by JFreeChart, this component is only a thin wrapper to simplify its use within Echo applications.

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.

The Echo3 File Transfer Library provides support for uploading and downloading files to and from Echo3 applications (client-side or server-side). It uses the the Apache Commons File Upload library to process uploaded files.

The library consists of an UploadSelect component which provides support for selecting and uploading files, and a DownloadCommand which will download a file to the user.

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.
• Echo3 Chart: Server-side library providing charting support based on JFreeChart.

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.