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WatG Browser | WatGBrowser-v2.0.1
 Overview  Features

The WatG Browser (What is at the Grid Browser) is a web-based Grid Information System (GIS) visualization application providing detailed overview of the status and availability of various Grid resources in a given gLite-based e-Infrastructure. It is able to query and present data obtained from Grid information systems at different layers: from local resource information system for a particular Grid service (GRIS), to the Grid site information system (site BDII), and to the top-level information system for the whole Grid infrastructure (top-level BDII).

The efficient implementation of WatG Browser allows quick and easy navigation through entries and objects of the LDAP tree retrieved by the specified query, even if the size of the output is huge and hierarchically very complex. Highly responsibility is achieved with implementation of partial refreshes and asynchonization of a web page. A partial refresh of WatG application can be observed when an interaction event is triggered, for example click on the plus icon of the LDAP tree. The server processes the information and returns a limited response specific to the data it receives, for example LDAP's subtree that requires given condition. One may notice that WatG server does not send back an entire page, like the conventional "click, wait and refresh" web applications. Instead, WatG client updates the page based on the response. This means that only part of the page is updated. In other words, WatG's initial page is treated like a template: WatG server and client exchange the data and the client updates parts of the template based on the data it receives from the server. Another way to think about it is to consider WatG application as driven by events and data, whereas conventional web applications are driven by pages. Asynchronization of the WatG application is reflected in the fact that after sending data to the server, the client can continue processing while the server does its processing in the background. During all this, a user can continue interacting with the client without noticing interruption or a lag in the response. For example, a user can click on any plus or minus icon even during the loading, and in that way a new request will be created and executed afterwards. The client does not have to wait for a response from the server before continuing, as is the case in the traditional, synchronous approach. Architecture of the WatG Browser is given below.

[WatG Browser architecture]

The above main features of WatG application introduce also many secondary ones. For example, a partial refresh hides huge complexity and amount of data stored in a Grid Information System, which have to be transferred from the server to the client. Therefore, WatG is able to browse large LDAP directories keeping out of sight its nontrivial structure and size.

Current WatG front-end performs a search using the filter. Search filters enable defining search criteria and provide more efficient and effective searches. The filter should conform to the string representation for LDAP filters. The WaiG front-end also contains attribute field, which returns only selected entries and values if specified.

 Implementation

WatG application is written in the Java programming language. GWT (Google Web Toolkit) is used to cross-compile it into the optimized JavaScript that automatically works on all major browsers.

 Presentations

Nov 2011 - WatG Browser at EGI AppDB [URL]

Sep 2011 - WatG Browser at EGI TF 2011 conference [PDF]

Mar 2011 - WatG Browser in Journal of Grid Computing [PDF]

Dec 2009 - WatG Browser at SEE-GRID-SCI User Forum [PDF]

Sep 2009 - WatG Browser poster at EGEE'09 conference [PDF]

 Developer

Dusan Vudragovic <dusan at ipb.ac.rs>