Operations

In class diagrams, an operation requests a service that a classifier or an instance of a class is called to perform. Operations are contained by classes. A classifier can have any number of operations or none at all.

Operations are implementations of functions or queries that an object might be called to perform. A well-defined operation does only one thing.

For example, you can make a Cart class responsible for adding and removing merchandise that a customer plans to buy. Then you can add an addItem() operation that adds merchandise to the cart and a removeItem( ) operation that removes merchandise.

In class diagrams, C/C++ methods map to UML class operations or behaviors.

As the figure in the following table illustrates, operations are shown in the operation compartment of a shape in a UML class diagram.

C/C++ source code UML visualization
C/C++ operations are displayed. A diagram illustrating C/C++ operations.

You can show, hide, or collapse the operation compartment, and show or hide the compartment title. You can also specify the visibility styles of operations as text symbols (such as "+") or icons (such as Image showing an Eclipse Protected visibility icon for operations.).

Parent topic: Class diagrams and diagram elements

Related concepts
Classes
Class diagrams
Relationships
Attributes
Multiplicity
Visibility

Related tasks
Changing the default for showing attribute and operation compartments

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