This topic contains 4 replies, has 1 voice, and was last updated by Yuvi 2 years, 11 months ago.
March 26, 2015 at 11:21 am #1830
Creating the POST Design Class Diagrams
◦ 1. Identifying Software Classes
The first step in the creation of design class diagrams is to
identify those classes that participate in the software
These can be done by scanning all the interaction diagrams
and listing the classes mentioned
Note that many of the concepts in the conceptual model,
such as Cashier, Manager and Item, are not present in the
There is no need – for the current development cycle – to
represent them in software.
2. Add method names
The methods of each class can be identified by analyzing
the collaboration diagrams.
For example, if the message makeLineItem is sent to an
instance of class Sale, then class Sale must define a
March 26, 2015 at 11:21 am #1831
3. Adding more type information
The type of the attributes, method parameters, and
method return values may all optionally be shown.
The question as to whether to show this information
or not should be considered in the following context:
If it is being created in a CASE tool with automatic code
generation, full and exhaustive details are necessary.
If it is being created for software developers to read,
exhaustive detail may adversely effect the noise-to-value
March 26, 2015 at 11:22 am #1832
4. Adding Associations and Navigability
In a design class diagram, associations are chosen by
a Spartan software-oriented, need-to-know criterion
i.e. what associations are required to satisfy visibility
needs indicated by the interaction diagrams.
This is in contrast with associations in the conceptual
model, which may be justified by the intention to
enhance comprehension of the problem domain.
Here are common situations suggesting a need to
define an association:
A sends a message to B.
A creates an instance B.
A needs to maintain a connection to B.
March 26, 2015 at 11:23 am #1833
5. Adding Dependency Relationships:
The UML includes a general dependency relationship
which indicates that one element has knowledge of
It is illustrated with a dashed arrowed line.
In class diagrams the dependency relationship is
useful to depict non-attribute visibility between
In other words, parameter, global, or locally declared
For example, the POST software object receives a
return object of type ProductSpecification from the
specification message it sent to a ProductCatalog
March 26, 2015 at 11:24 am #1834
Creating Design Class Diagram
Apply the following complete strategy to create a
Design Class Diagram:
1. Identify all the classes participating in the software
Do this by analyzing the interaction diagrams.
2. Draw them in a class diagram
3. Duplicate the attributes from the associated concepts
in the conceptual model.
4. Add method names by analyzing the interaction
5. Add type information to the attributes and methods.
6. Add the associations necessary to support the required
7. Add navigability arrows to the associations to indicate
the direction of attribute visibility
8. Add dependency relationship lines to indicate nonattribute
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