A package in the

Unified Modeling Language The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system. The creation of UML was originally m ...

is used "to group elements, and to provide a namespace for the grouped elements".OMG Unified Modeling Language (OMG UML), Infrastructure, V2.1.1
p.158. A package may contain other packages, thus providing for a hierarchical organization of packages. Pretty much all UML elements can be grouped into packages. Thus, classes, objects,

use case In software and systems engineering, the phrase use case is a polyseme with two senses: # A usage scenario for a piece of software; often used in the plural to suggest situations where a piece of software may be useful. # A potential scenario ...

s, components, nodes, node instances etc. can all be organized as packages, thus enabling a manageable organization of the myriad elements that a real-world UML model entails.

Usage

When organizing functional models (use case models, workflow models etc.), use packages to model the real-world modular structure of the system being modeled. When organizing source code, use packages to represent the different layers of the source code. For instance: *

presentation layer In the seven-layer OSI model of computer networking, the presentation layer is layer 6 and serves as the data translator for the network. It is sometimes called the syntax layer. Description Within the service layering semantics of the OSI netw ...

* controller layer *

data access layer A data access layer (DAL) in computer software is a layer of a computer program which provides simplified access to data stored in persistent storage of some kind, such as an entity-relational database. This acronym is prevalently used in Microsof ...

* integration layer * business services layer When organizing component models, use packages to group the components according to ownership and/or reuse possibilities. For instance: * commercial-off-the-shelf products * open-source framework components * custom-built framework components * custom-built application components When organizing deployment models, use packages to represent the different types of deployment environments that you will be modeling. For instance: * production environment * pre-production environment *

integration test Integration testing (sometimes called integration and testing, abbreviated I&T) is the phase in software testing in which individual software modules are combined and tested as a group. Integration testing is conducted to evaluate the complianc ...

environment * system test environment *

development environment In software deployment, an environment or tier is a computer system or set of systems in which a computer program or software component is deployed and executed. In simple cases, such as developing and immediately executing a program on the same m ...

References

Unified Modeling Language {{uml-stub