Architecture, Deployment Diagrams, Web Modeling

Elizabeth BigelowCS-15499COctober 6, 2000

Today

New scheduleProject next stepsFeedback Architecture in the object oriented senseDeployment diagramsEvent systems

Schedule

Please note that schedule for presentations and mentoring sessions has been updated on the webTeams D, E, F present WednesdayMentoring sessions on FridayTwo lectures on Monday

Some thoughts

Why do a particular diagram… UML diagrams allow you to look at a

problem from different perspectives Keeping the details straight on a big

project is a major problem Big advantage in entering data once (if

possible) Diagrams are not totally orthagonal,

but at least parts that are can be tracked

Why….

Payoff on modeling analysis & cross-checking communication

Bicycle for the mindCombination of modeling and human analysis can yield much more than narrow area of modelTrick is to know when to stop

Project Next Steps and Feedback

First presentations were in general very good The primary goal was to convey to the class what the project was aboutMost teams participated evenlyEvent systems requested were not included

Next steps

Refine class association diagrams to show all attributes and methodsCreate behavioral diagrams for key areas (particularly those that can change state on the site, as opposed to sheer display)Create deployment and web modelsAnalyze diagrams individually and together to see what has to be changed for implementation

Presentations

Teams D, E, F should give presentations much like the previous ones, but show their diagrams at a greater level of development (particularly behavioral)All teams should create deployment and web diagrams for mentoring session and be prepared to show results of cross diagram analysis

Analysis

Consistency checking (create forms for yourself to document your checks. Some people find it helpful to use copies of diagrams)Support for major queries and processesDocument potential run time problemsDetermine whether implementation object model should change Will your code track exactly to the model?

Why or why not

Architecture and UML

In UML, there are five views Structural view (Class Diagrams,

Object Diagrams) Implementation View (Component

Diagrams) Environment View (Deployment

Diagrams) Behavioral View (Sequence Diagrams,

Collaboration Diagrams, Statechart Diagrams, Activity Diagrams)

Component Diagrams

Show relationships and dependencies among sets of code without respect to actual physical placement of codeUse only when there is a design issue

Deployment Diagrams

Called “environment” diagramShows actual physical organization of computation units and connectorsAppropriate to do at this stage--when user requirements are fairly well articulatedMay surface practical problemsShould use for “what if’s” (volume, network failures, etc.)

Deployment Diagrams

The Web

To date, we’ve looked at application objectsNow, we need to look at objects and components in terms of building web applications

Object oriented?

Fundamental component is the pageWeb servers distribute pages of information to browsersBrowser acts as generalized user interface container (specifics defined by each page’s content)Pages may be a combination of static HTML and dynamic scripted pages (ASP)

Scripted Pages

Scripted pages contain code executed by web server (scripting engine or page filter) ultimately building an HTML formatted pagePage is sent back to browser that requests it

Web Client Server

Connection exists only during a page request (connection is broken once the request is fulfilled)Business logic on the server is only activated by the execution of scripts inside the pages requested by the browserUltimate result is to update the business state of the server and prepare an HTML formatted page to the requesting browser

Issues

Business objects are not always accessible when handling individual requests

Client Scripting

As opposed to server side (procedural), are event drivenHave no access to server resources

Forms

Necessary to collect informationEach form associated with an action pageWeb server finds page and executes the page’s code

Components

Server -- there may be an intermediate tier with business logicClient may have components for execution on clients machine.In order model these effectively, UML extensions have to be used

Stereotypes

Special types of classes and relationships for special, well defined purposesUse only when necessary_Really_ necessary for effective web modelingSee www.rational.com/products/whitepapers/100462jsp