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 4
The current stable Tapestry release is version 4.1. Version 4 and below are relatively similar, whereas version 5 contains substantial changes.
Tapestry 4 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 through 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 5
Tapestry version 5 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, currently in beta release, 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 when a template or Java class is changed. Tapestry has accomplished this though the evolution of HiveMind and IoC. Because of these technologies, there is no longer any need for a middle XML layer. The back end has been simplified to use Plain Old Java Objects, and is linked directly to the front end using Java annotations. The front end itself has been redesigned from scratch to use a new XML-based language known as the Tapestry Markup Language (TML). Version 5 also integrates AJAX interfacing fully into its control structure, allowing for developers to create rich immersive web application with very little code.
Related projects
Tapestry is used in the Trails Framework.
References
- ^ Tapestry in Action - Preface by Howard Lewis Ship
External links
|
