Composition, a type of aggregation

1. composition,  ( composite aggregation in UML), is part – whole relationship
2. Winston et al describes describes several kind composition, with three basic properties 
   1. configuration  (functional or structural relationship between part and whole)
   2. homeomerous (parts are the same kind of as the whole or not)
   3. invariance (parts can be separated from the whole or not)
3. based in these three properties the following kind of composition can be ascertained
   1. component – integral object composition (the integral whole is formed by the individual components, which can be removed but removing them will disintegrate the whole, like a laptop is made of different hardware components)
   2. material – object composition (the object is made is up the material, and the material cant be removed from the object, or it can be said that the object is made up of the material, like a cooking pan is made of steel)
   3. portion – object composition (portions are homeomeric with the object, like a link list is made up of individual nodes, in which each node can be considered as portion of the link list, each portion can be removed from the object)
   4. place – area composition (place within the area, and place cant be removed from the area, like pune is in India)
   5. member – bunch composition (members are just a collection which forms a bunch, like flowers in a bouquet)
   6. member – partnership composition (members are invariant part of the partnership, if parts are removed whole is destroyed)

Reference :

• Winston, Morton E., Roger Chaffin, and Douglas Herrmann, "A Taxonomy of Part-Whole Relations," Cognitive Science, 11, 1987, pp. 417-444.
• Six Different Kinds of Composition, by James J. Odell 

UML Class diagram notation

1. name
2. attributes (data)
3. behavior (messages and operations)
4. constraints
5. tagged values
6. stereotypes

UML Class Diagram

1. static view of the model
2. describes what the class attributes (data) are, and also the behavior in terms of
   1. how to use (create, modify) the data
   2. what are the messages the class understand
   3. operations appropriate for each message
3. very good at depicting
   1. relationship among the classes and interfaces
   2. generalization
      • inheritance
      • base-derived
      • type-of relationship
   3. aggregation
      • lighter aggregation
      • stronger composition
      • whole-part relationship
   4. association
      • connections
      • have-a relationship
      • cardinality, whether the association is compulsory or not
      • modality, how many instances of class “A” for a given instance of class “B” when class “A” and “B” are in association (zero, one or many)
      • role, each class has with respect to the other class in the association

UML Interaction Diagram

1. sequence diagram
2. communication diagram
3. timing diagram
4. interaction overview diagram

UML Behavior Diagrams

1. use case diagram
2. activity diagram
3. state machine diagram

UML Structure Diagrams

1. class diagram
2. object diagram
3. component diagram
4. composite structure diagram
5. package diagram
6. deployment diagram

UML

1. Unified Modelling Language
2. Specified by OMG (Object Management Group)
3. How to express what you have in mind about the
   
   1. design of a software system
   2. components of a software system and their behaviour
   3. interactions between the components of a software system
4. An abstract view of what the software system is intended to be
5. Express the results of your analysis and design using
   
   1. structure diagrams (6)
   2. behaviour diagrams (3)
   3. interaction diagrams (4)