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Apache Tapestry
Developer	Apache Software Foundation
Latest release	4.1.2 / July, 2007
OS	Cross-platform
Genre	Web Framework
License	Apache 2.0 license
Website	[1]

Tapestry is an object-oriented Java web application framework to implement applications in accordance with the model-view-controller design pattern. Tapestry was created by Howard Lewis Ship independently, and was adopted by the Apache Software Foundation. Tapestry emphasizes simplicity, ease of use, and aims to avoid forcing programmers to create enormous blocks of "glue code". Tapestry uses a modular approach to web development, by having strong binding between user interface components (objects) on the web page and their corresponding Java classes. This component-based architecture borrows many ideas from WebObjects^[1].

Tapestry web applications are broken down into pages and components. Pages dictate component layout, whereas components dictate functionality. This approach separates complex applications into easily manageable snippets of code which handle user interactions, business logic, and persistent data. Components are broken down further into core and supplemental types. Core components are the basic building blocks to the application, such as form validation, interface assets, or persistent objects. Supplemental components define how a group of any core components may interact with other in the group.

Component templates in Tapestry are XHTML files. Typically an XML file defines the mapping between Java classes and the XHTML objects they control. The communication between the backend Java and frontend (web application programming) XHTML objects is handled though OGNL. The code is marked up differently from the typical mechanism used by PHP, ASP, and JSP, which use special tags to enclose template variables and code.

Tapestry has remained relatively similar throughout its versions with the exception of Tapestry version 5. This version began development shortly after version 4 was released. The developers of tapestry version 4 quickly realized that their original architecture would not solve many problems plaguing its web developers using its framework. These problems included complex component architecture and persistent data mapping. As well as the need to recompile, archive, deploy, and restart their servlet. This process needed to be done for every change made to the application. These problems affect a majority of all popular web application frameworks. Ultimately the worse problem afflicting tapestry developers was the lack of backwards compatibility.

Tapestry version 5 which is scheduled to be released in the fall of 2007, has been redeveloped from the ground up. This version is designed to be 100% backward compatible for future version releases though the adoption of Java annotations. This version also allows for instant development. There is no need for the developer to redeploy and restart their servlet container. Tapestry has accomplished this though the evolution of HiveMind and IoC. The implementations of these technology do not require developers to use XML to link the back-end Java classes with their respective front end XHTML objects. The tapestry core modular automates this process entirely. This version also integrates AJAX interfacing fully into its control structure, allowing for developers to create rich immersive web application with very little amount of code.

1. ^ Tapestry in Action - Preface by Howard Lewis Ship

• Tapestry Home Page
• Howard Lewis Ship
• Tapestry in Action book
• Enjoying Web Development with Tapestry book