UML Class Relationships

Types of relationships in UML class diagram §

1. Dependencies
2. Generalizations
3. Associations

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Dependencies §

• Indicates semantic relationship btw two classes

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Generalizations §

• Connects a sub class to it’s super class (Inheritance basically)

• Reverse is called specialization

  

Note

JAVA doesn’t support multiple inhertence

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Association §

• A communication btw two classes

• We can name the association

• We can use dual association,

• We can define navigatability,

• Association can be objects themselves (association or link classes)

• Self association is possible

  

• Composition and Aggregation are sub types

Aggregation §

• Indicates a “part-whole” relationship
• Denoted by a hallow diamond

Composition §

• Indicates strong ownership (stronger form of aggregation)
• Life time of the part is intertwined on the lifetime of the whole
• Denoted by a filled diamond

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Summary §

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Related Ideas §

• Depicting Class in a UML diagram

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Sources §

• Design Patterns CA Prep