Class Attributes

Specifying Class Attributes

All classes support the attributes listed in the following table. Attributes enable you to modify the behavior of class. Attribute values apply to the class defined within the classdef block.

classdef (Attribute1 = value1, Attribute2 = value2,...) ClassName
   ...
end
For more information on attribute syntax, see Attribute Specification.

Class Attributes

Attribute Name

Class

Description

Abstract

logical

(default = false)

If specified as true, this class is an abstract class (cannot be instantiated).

See Abstract Classes for more information.

AllowedSubclasses

meta.class object or cell array of meta.class objects

List classes that can subclass this class. Specify subclasses as meta.class objects in the form:

  • A single meta.class object

  • A cell array of meta.class objects. An empty cell array, {}, is the same as a Sealed class (no subclasses).

Specify meta.class objects using the ?ClassName syntax only.

See Specify Allowed Subclasses for more information.

ConstructOnLoad

logical

(default = false)

If true, MATLAB® calls the class constructor when loading an object from a MAT-file. Therefore, implement the constructor so it can be called with no arguments without producing an error.

See Initialize Objects When Loading for more information.

HandleCompatible

logical

(default = false) for value classes

If specified as true, this class can be used as a superclass for handle classes. All handle classes are HandleCompatible by definition. See Handle Compatible Classes for more information.

Hidden

logical

(default = false)

If true, this class does not appear in the output of the superclasses or help functions.

InferiorClasses

meta.class object or cell array of meta.class objects

Use this attribute to establish a precedence relationship among classes. Specify a cell array of meta.class objects using the ? operator.

The fundamental classes are always inferior to user-defined classes and do not show up in this list.

See Class Precedence and Dominant Argument in Overloaded Graphics Functions.

Sealed

logical

(default = false)

If true, this class cannot be subclassed.

Framework attributes

Classes that use certain framework base classes have framework-specific attributes. See the documentation for the specific base class you are using for information on these attributes.

Specifying Attributes

Attributes are specified for class members in the classdef, properties, methods, and events definition blocks. The particular attribute setting applies to all members defined within that particular block. You can use multiple properties, methods, and events definition blocks to apply different attribute setting to different class members.

Superclass Attribute Values Are Not Inherited

Class attributes settings are not inherited, so superclass attribute values do not affect subclasses.

Attribute Syntax

Specify class attribute values in parentheses, separating each attribute name/attribute value pair with a comma. The attribute list always follows the classdef or class member keyword, as shown:

classdef (attribute-name = expression, ...) ClassName

   properties (attribute-name = expression, ...)
      ...
   end
   methods (attribute-name = expression, ...)
      ...
   end
   events (attribute-name = expression, ...)
      ...
   end
end

Class-Specific Attributes

Some MATLAB classes define additional attributes that you can use only with the class hierarchies that define these attributes. See the specific documentation for the classes you are using for information on any additional attributes supported by those classes.

Related Topics