Package diagram

Packages containing nodes and artifacts.

A package diagram in the Unified Modeling Language depicts the dependencies between the packages that make up a model.

Overview

In addition to the standard UML Dependency relationship, there are two special types of dependencies defined between packages:

• package import
• package merge

A package import is "a relationship between an importing namespace and a package, indicating that the importing namespace adds the names of the members of the package to its own namespace." ^[1] By default, an unlabeled dependency between two packages is interpreted as a package import relationship. In this relationship elements within the target package will be imported in source package.

A package merge is "a directed relationship between two packages, that indicates that the contents of the two packages are to be combined. It is very similar to Generalization in the sense that the source element conceptually adds the characteristics of the target element to its own characteristics resulting in an element that combines the characteristics of both"^[2]

Packages containing use cases.

In this relationship if an element exists within source element's definition and target also then the source element's definition's will be expanded to include target element's definitions.

it's different from a class diagram.

Elements

1. Package: It is a general purpose mechanism for organizing model elements & diagrams into groups. It provides an encapsulated namespace within which all the names must be unique. It is used to group semantically related elements. It is a namespace as well as an element that can be contained in other package's namespaces.
2. Class: It is a representation of objects, that reflects their structure and behavior within the system. It is a template from which actually running instances are created. Classes usually describe logical structure of system.
3. Interface: It is a specification of behavior. Implementing classes of an interface class are required to support the behavior.
4. Object: It is an instance of class. It is often used in analysis to represent numerous artifacts and items that exist.
5. Table: It is a stereotyped class.

Usage

Package diagrams can use packages containing use cases to illustrate the functionality of a software system.

Package diagrams can use packages that represent the different layers of a software system to illustrate the layered architecture of a software system. The dependencies between these packages can be adorned with labels / stereotypes to indicate the communication mechanism between the layers.

References

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2009)

External links

Wikimedia Commons has media related to: Package diagrams

• Introduction to UML 2 Package Diagrams by Scott W. Ambler
• UML 2 Package Diagrams

v t e Unified Modeling Language Actors Organizations Object Management Group UML Partners Persons Grady Booch Ivar Jacobson James Rumbaugh Concepts Object oriented Object-oriented programming Object-oriented analysis and design Structure Actor Attribute Artifact Class Component Interface Object Package Profile diagram Behavior Activity Event Message Method State Use case Relationships Aggregation Association Composition Dependency Generalization (or Inheritance) Extensibility Profile Stereotype Other Multiplicity Diagrams Structure Class Component Composite structure Deployment Object Package Behaviour Activity State Machine Use case Interaction Communications Sequence Interaction overview Timing Derived languages Systems Modeling Language (SysML) UML eXchange Format (UXF) XML Metadata Interchange (XMI) Other topics Glossary of UML terms Rational Unified Process Comparison of UML tools UML colors