Dekoh Desktop consists of 3 layers as shown below. The bottom-most layer ("Web Server") is mandatory part of Dekoh Desktop and applications could be written for deployment on any of the three layers, as shown. The Web Server and Extended Services layers together form the "Dekoh Runtime".

Dekoh Runtime

Dekoh Runtime is the core of the platform, providing all infrastructural services for applications.

As part of the Dekoh Runtime is an optimized Web Server which implements JavaServer Pages (JSP) and Servlet standards. Applications packaged as Web Archive files (WAR) for standard web containers such as Apache Tomcat, can be deployed on this Web Server. You can also use open deployment format by adding applications to public_html directory.

The Web Server also has two additional modules Security and Routing. Security module checks every URL request to ensure that authorized access is being made. Routing module provides a secure channel between Dekoh Desktop and Dekoh Network.

Extended Services layer consists of the following:

• Database. Apache Derby database that can be used to store application data and metadata
• Java Persistence API (JPA). Toplink JPA is included to provide persistence management and O-R mapping
• Version Manager. Version checks, installation management and preferences framework
• Web Remoting. Direct Web Remoting (DWR)to provide access to JavaScript from Java; optionally OpenAMF is included to provide access from Flash to Java
• RSS. Rome utilities to generate and/or consume RSS and Atom feeds

The user interface for a Dekoh application will be served locally by the Dekoh Runtime to the web browser. It can be built using DHTML, Javascript, CSS, Ajax, Flash, JSP and Servlet technologies. Additionally, applications can use any Ajax, Javascript libraries and bundle them. Web Remoting support is provided for Javascript and Flash to call backend Java classes from the UI.

The Portal Framework

Applications built on top of Portal Framework, automatically get facilities such as object-level persistence, sharing, tagging, rating, commenting, etc. typically common in Web2.0 applications.

Portal Framework is designed for organizing, managing and sharing personal digital assets; referred to as Digital Object (DIO). DIO is an abstraction for personal content, such as Photos, videos, music, bookmarks, web clips, documents, etc.

The DIO Entity Package, implements many common functions such as sharing, tagging, commenting, rating, import and life-cycle operations (add, remove, move, rename). Dekoh app writer simply extends the base classes of DIO Entity package. DIO entities are implemented using JPA and make use of the inbuilt database of the platform.

Portal Framework also comes bundled with library of commonly required widgets such as location chooser, file chooser, tag cloud, and more.

Dekoh application user interface could be multi-lingual and developers can make use of support provided by the Portal Framework for developing such interfaces.

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