Component Diagrams

A component is part of the system that exists when the system is operating. The component modeling focuses on modeling the implementation of the system. The component view focuses on the big picture and tries to break the system down into major functional areas.

One can conceive of a business system that has a user interface, an accounting component, a business rules component, a reporting element, a data component and communicationsetc.


Each of these components behaves much like the classes that we saw earlier. In addition, there are component instances, which behave much like objects.. For instance, one can see a web piece of a user interface, as well as a client/server (desktop) interface. One can also easily imagine a set of business rules for purchasing and one for A/R.

Nodes are physical resources that are available to the system when it is running. Examples might be a desktop computer, laser printer, a linux server, an IIS Server, etc. Nodes are represented by labeled rectangular solids.

Like classes and components, nodes will also have objects patterned after them, which represent specific instances of those node classes. Examples might be Chris’ Desktop Computer, a specific laser printer, etc. Like the classes and components, nodes may have attributes and methods, as well as components which can have access to them.


Deployment Diagrams

Dependency between items is shown as a dotted line with an arrow pointing to the supplier. So, for instance, an accounting system with a bar code reader package would look like this:


Other examples of these dependencies might be a system, which collects in batch mode entries coming in from email. The pre-processing package would assemble and format the pertinent accounting entries into a tidy – already balanced entry file from the email before submitting it to the accounting system.

Also useful in deployment diagrams is the communication association. Communications are shown using a straight line, similar to the link shape in the class diagram. These links, like the dependencies may have names, constraints, and stereotypes and methods to communicate transitivity to other classes/components.



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