Java Data Objects

The Web Tier

The Web Tier

Whoooaaaa, 'Web Tier' ? Where did that come from ?? We were only recently told that:

Typically, multi-tiered applications have a client tier, a middle tier, and a data tier (often called the enterprise information systems tier).

The client tier consists of a client program that makes requests to the middle tier (nested Property version)

Java EE application development concentrates on the middle tier to make enterprise application management easier, more robust, and more secure.

So how does 'The Web Tier' fit in with the idea of a 'middle tier' ? And what about the 'business tier', which deeper source text «wrapper» Components now refer to; how is that related to what we were already told ?

The middle tier's business functions handle client requests and process application data, storing it in a permanent datastore in the data tier: NESTED PROPERTY FORM

Are these new tiers parts of the 'middle tier', i.e., are they sub-tiers ? Let's now use UML™ Parsing Analysis to sort it out.

However first please note in advance:

The source text of some of the deeper «wrapper» Components shown here already suggest "designed" Java EE Classes that may be reverse engineered and bound through UML™ Parsing Analysis, so that these «wrapper» Components may eventually be "executed" as demonstrations from within a UML tool !

Under UML™ Parsing Analysis it is important, however, to till include the analysis step, rather than just jumping straight to the design (or "already designed") layer, because the analysis classes will provide an important organisational bridge.

The Client Tier

The Client Tier

As in the source document Your First Cup: An Introduction to the Java EE Platform, we move now into more detail concerning the tiers.

A few of the existing analysis elements are included in the «wrapper» Component.This is typical of the UML™ Parsing Analysis process; the first diagrams often take a lot of work - and more time - and involve the creation of more implied analysis elements. As one works through a source text there are usually fewer and fewer new terms, and if the text is coherent and has good "a signal to noise ratio", the modelling begins to converge rapidly.

Keep in mind also; the aim is none other than to make these wrapped words run ! It should be possible to click on the «wrapper» Components above and have them trigger execution of something relevant to Java EE via a URL that expresses this analysis, and binds it to existing Java EE "designed" Classes, and indicated above, also to non-Java clients.

Scientific IT Consultant and UML+Java developer (radioastronomy)

10/2003 - 04/2004

Developed a Java-based information system and UML entity model for the MOST radio-telescope using Java Data Objects (JDO) persistence and JavaServer Pages (JSP) web technologies, including a Java3D modelling and animation client, a JSP web client, and a Java Swing client. Employed Unified Modeling Language (UML) analysis, design, reverse-engineering, and documentation throughout the project in conjunction with the Unified Software Development Process.

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