Tools. Enhydra offers a set of tools that help build a Web application. The most 
important tools are listed below. 
Enhydra separates the application logic into three layers: The presentation layer, the business 
layer, and the data layer. Following this concept ensures that the designers can independently 
work on the presentation while software engineers work on the application logic. Providing three 
distinct layers also increases the maintainability of the code. 
2.3.3.3  The Enhydra Application Framework Models 
   The Enhydra super servlet application model contains a single servlet that manages all 
presentation objects (presentation objects generate the Web pages). This application 
controller servlet has to be derived from a class provided by the Enhydra architecture. A 
new presentation object is instantiated with each request. 
   The servlet application model is the model described by Sun for so called  Web 
applications . With this model, several servlets are usually written to respond to the 
requests. The servlets are instantiated at start time of the application, and then executed 
many times in separate threads. 
2.3.3.4 Enhydra 
Tools 
   The Application Wizard serves to generate an initial source tree for the development, 
including make files. While this could be done manually, it can definitely save time during 
the start up phase of a project. 
   The Extensible Markup Language Compiler XMLC is the tool that allows the clean 
separation of the user interface and the application logic. It is used to compile an HTML 
page into a Java class containing the whole page as a hierarchy following the W3C's 
Document Object Model (DOM). The obtained Java class can then be programmatically 
modified by replacing nodes or attributes with dynamic content.  
This method has the following advantage: A designer can independently create a Web 
page with his/her design tool of choice. Then, the programmer compiles the HTML page 
and accesses the desired contents via attribute IDs. 
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