User`s manual

Creating and Using Java Objects

5-17

Accessing Data from a Static Field

In Java, a static data field is a field that applies to an entire class of objects.

Static fields are most commonly accessed in relation to the class name itself in

Java. For example, the code below accesses the

WIDTH field of the Frame class

by referring to it in relation to the package and class names,

java.awt.Frame,

rather than an object instance.

width = java.awt.Frame.WIDTH;

In MATLAB, you can use that same syntax. Or you can refer to the WIDTH field

in relation to an instance of the class. The example shown here creates an

instance of

java.awt.Frame called frameObj, and then accesses the WIDTH field

using the name

frameObj rather than the package and class names.

frame = java.awt.Frame('Frame A');

width = frame.WIDTH

width =

Assigning to a Static Field

You can assign values to static Java fields by using a static set method of the

class, or by making the assignment in reference to an instance of the class. For

more information, see the previous section, “Accessing Data from a Static

Field”. You can assign

value to the field staticFieldName in the example

below by referring to this field in reference to an instance of the class.

objectName = java.className;

objectName.staticFieldName = value;

Note MATLAB does not allow assignment to static fields using the class

name itself.

Determining the Class of an Object

To find the class of a Java object, use the query form of the MATLAB function,

class. After execution of the following example, frameClass contains the name

of the package and class that Java object

frame instantiates.