UML Diagrams

UML 2 describes 13 official diagram types listed in Table 1.1 and classified as indicated on Figure 1.2. Although these diagram types are the way many people approach the UML and how I've organized this book, the UML's authors do not see diagrams as the central part of the UML. As a result, the diagram types are not particularly rigid. Often, you can legally use elements from one diagram type on another diagram. The UML standard indicates that certain elements are typically drawn on certain diagram types, but this is not a prescription.

Table 1.1. Official Diagram Types of the UML

Diagram	Book Chapters	Purpose	Lineage
Activity	11	Procedural and parallel behavior	In UML 1
Class	3, 5	Class, features, and relationships	In UML 1
Communication	12	Interaction between objects; emphasis on links	UML 1 collaboration diagram
Component	14	Structure and connections of components	In UML 1
Composite structure	13	Runtime decomposition of a class	New to UML 2
Deployment	8	Deployment of artifacts to nodes	In UML 1
Interaction overview	16	Mix of sequence and activity diagram	New to UML 2
Object	6	Example configurations of instances	Unofficially in UML 1
Package	7	Compile-time hierarchic structure	Unofficially in UML 1
Sequence	4	Interaction between objects; emphasis on sequence	In UML 1
State machine	10	How events change an object over its life	In UML 1
Timing	17	Interaction between objects; emphasis on timing	New to UML 2
Use case	9	How users interact with a system	In UML 1