JSP Custom Tag Library for In-Place Editing in Disconnected Architecture – A Case Study

Abstract

Even a trivial web application involves some sort of database functionality with few basic operations. However, such applications reveal a lot of code repetition. To avoid such a scenario, various techniques have been proposed in literature for reusability of code. One such technique is implementing custom tag library. Many frameworks rely on their own proprietary tag libraries for compacting the code. For example, struts framework abundantly uses HTML tag library, Beans tag library and Logic Tag library. JSF frame work utilizes core tag library. Connected architecture suffers from severe limitations and has become obsolete in web applications where no. of users and hence no. of database connections is not predetermined. In such a scenario connected architecture becomes predominant and scores well on its connected counterpart. In order to cater this need of a typical web application, in this paper, authors have presented JSP tag libraries for in-place editing in disconnected architecture. The tag currently works with MS-Access, MySQL and Oracle and can easily be extended to incorporate other back ends. Current work reveals encapsulation basics targeting the elimination of boilerplate code where lot of repeated code is hidden behind custom tags. Such a mechanism boils down to the entire database operations to one liner when tag attributes conceal the plethora of information involved in implementation of functionality. This paper emphasizes on development of a generic tag for disparate back ends. The database extensions are properly taken care of. The proper data type casting is performed by pulling out database schema information from the underlying DBMS. The communication between Tag Handler class and JSP page is established through PageContext class. The name of JSP page becomes available to the Tag Handler class through PageContext class which can also be used for retrieving query string parameters in a Tag Handler class. Keywords-Disconnected Architecture, JDOM Parser, PageContext Class, Tag Handler Class, TagLib Directive, XML.