Playing with UML Diagrams

Class Diagram

Single block:

----------------------------
CLASS NAME
----------------------------

ATTRIBUTES
----------------------------


FUNCTIONS
----------------------------

Access Modifier or Class Visibility notations:

+ Public
- Private
# Protected
~ Package Local

Params in methods can be decribed in terms of its direction wrt to the caller:

MethodA(in a: int): int => takes in a, does not modify it
MethodB(out a: str): int => returns a after modification
MethodC(inout a: bool): str => takes in a, and modifies it

Class Diagrams can represent 3 different level of specification or perspective

Conceptual Perspective:

Diagrams that represent concepts that implement the classes and is language independent

Specification Perspective:

High level software specification, but not their implementation

Implementation Perspective:

Depict actual software implementation

Relationship between classes

Notations

Association:

• Connects classes
• Can specify verb describing association
• Muliplicity: number of obejcts taking part in the relationship. Eg: 1 to 1, 1 to many, many to many

Inheretence/Genrealization:

• Schematic relationship between parent class and its descendants
• Hollow arrow directed towards parent class
• Convention: Abstract classes names are written in italics

Realization:

• Relationship between interface and objects that implement this interface
• Special case of association of two classes

Dependency:

• When object of one class is used by another class, without being stored in a field

Aggregation:

• One class is a composite part of another
• If aggregate class deleted, the composite classes exist, but do not form the aggregate class

Composition:

• Once the classes forming the aggregator class are dropped, the aggregator class is also dropped

Component Diagram

Modelling aspects of OO systems that are used for visulaizing, defining, documenting component based systems. Essentially class diagrams that focus on system components, used to implement static view implementation of a system.

• Each component is responsible for one clear goal.
• Interacts with other essential elements in a need to know basis.

2 Types of Interfaces:

• Provided: System component interface.
• Required: Needed by system components to carry out function.

Similar Relationship symbols used as in Class Diagrams.