The Handle Superclass
Building on the Handle Class
handle class is an abstract class. Therefore, you cannot create objects of this class directly. Use the
handle class as a superclass to implement subclasses that inherit handle behavior. MATLAB® defines several classes that derive from the
handle class. These classes provide specialized functionality to subclasses.
Specialized Handle Base Classes
To add both handle behavior and specific functionality to your class, derive your class from these
For information on how to define subclasses, see Design Subclass Constructors.
Handle Class Methods
When you derive a class from the
handle class, the subclass inherits methods that enable you to work more effectively with handle objects.
List the methods of a class by passing the class name to the
Methods for class handle: addlistener findobj gt lt delete findprop isvalid ne eq ge le notify
Event and Listener Methods
For information on how to use the
addlistener methods, see Events and Listeners Syntax.
TF = eq(H1,H2) TF = ne(H1,H2) TF = lt(H1,H2) TF = le(H1,H2) TF = gt(H1,H2) TF = ge(H1,H2)
The handle class overloads these functions to support equality tests and sorting
on handles. For each pair of input arrays, these functions return a logical array of
the same size. Each element is an element-wise equality or comparison test result.
The input arrays must be the same size or one (or both) can be scalar. The method
performs scalar expansion as required. For more information on handle class
relational methods, see
Test Handle Validity
handle class method to determine if a variable is a valid handle object. For example, in the statement:
B = isvalid(H)
B is a logical array in which each element is
true if, and only if, the corresponding element of
H is a valid handle.
B is always the same size as
When MATLAB Destroys Objects
MATLAB destroys objects in the workspace of a function when the function:
Reassigns an object variable to a new value
Does not use an object variable for the remainder of a function
Function execution ends
When MATLAB destroys an object, it also destroys values stored in the properties of the object. MATLAB frees computer memory associated with the object for use by MATLAB or the operating system.
You do not need to free memory in handle classes. However, there can be other operations that you want to perform when destroying an object. For example, closing a file or shutting down an external program that the object constructor started. Define a
delete method in your handle subclass for these purposes.
See Handle Class Destructor for more information.