DNC Architecture

DNC Architecture

Having analyzed common problems and popular solutions we offer the following 3-tier architecture. The Front End is a web based client or a stand alone Java client. The Business Logic is implemented on a web server, for instance as a number of servlets or C++ CGI executables. The Back End is an SQL database, such as MySQL or Oracle. We will use XML over HTTP as a connection between the application server and the front end; and JDBC as a connection between the application server and the database. These are our preferences; so far – nothing new.

But in addition we will completely separate the three tiers by defining the front and back interfaces in a concise and language/layer independent form of XML clauses. These API definitions become the complete and final agreements between the GUI, server, and database. Ideally, such APIs will mean the same things for the developers of different layers, but in different terms. Thus, a web client developer is interested in what CGI parameters the web server expects and what XML data the server will issue back; but he is not interested in the internal representation of these parameters or data on the server side. Likewise, the database developer is interested in which stored procedures with which signatures he needs to implement, but he is hardly interested in which wrapper classes will be used to access his stored procedures and manage connections. Finally the application server developer will find convenient to use beans and wrapper classes with setter and getter methods for processing aggregated data, issuing screens and accessing stored procedures.

We claim our tool can support the interfaces as described above. The implementation is based on the idea that the API definitions can be used to generate servlet stubs and skeletons, screen classes, stored procedure wrapper classes, and aggregated data beans used throughout the whole application. The generated auxiliary classes will guarantee that the front end, application server, and the back end are consistent and can work together.

[DNC Framework]

Project Members:

• Rutishauser (admin)

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