You can use attributes to obtain the names of attributes owned by a class when you need class metadata in an OCL expression.

Purpose

attributes returns metadata about a class: a collection containing the names of the attributes that the class owns. It does not return the values held by an object.

For example, if a class owns the attributes Name, Age, and IsActive, the result contains the strings 'Name', 'Age', and 'IsActive'.

Return type

Item	Value
Return type	Collection(String)
Each collection item	The name of one attribute owned by the class

Example

Assume that the class Person owns these attributes:

Attribute	Example value on a Person object
Name	'Ada'
Age	37
IsActive	true

Using attributes for Person returns a Collection(String) with the attribute names:

Name
Age
IsActive

The result describes the class definition. It does not return 'Ada', 37, or true.

OCL Operation	Result
Product.attributes	['Price', 'DateAdded', 'Description', 'Name']

Use it as metadata

Use this operator when an expression needs to discover which attributes are defined on a class. Treat the result as a collection of strings: each item is an attribute name that you can inspect, compare, or present as metadata.

Do not use attributes when you need a particular object's data. In the example above, Name is an attribute name, while 'Ada' is that attribute's value.

See also

• Documentation:OCLOperators orderBy
• Documentation:OCLOperators addition
• Documentation:OCLOperators And
• Documentation:OCLOperators Or