Accessor, Mutator Methods

• For proper encapsulation, instance fields should be private, and should only be accessible to other classes via methods.
• This assists in debugging and data validation.
• An accessor method is a public method that simply returns the value of that instance field.
• It can either return the value itself, or it can perform some manipulation first.  It can also change related fields.
• A mutator method changes the value of an instance field.  It is also a public method.
• As a matter of fact, the JavaBeans standard specifies a syntax to do so.
• The instance fields must be declared private, and the first letter of the variable name must be lower case.
• The name of the accessor method starts with get, then the name of the instance field, capitalized.
• The name of the mutator method starts with set, then the name of the instance field, capitalized.
• For boolean values, the accessor method will often start with is instead.
• The JavaBeans concept is important.
• It allows custom GUI  components to be added to an IDE.
• It is also widely used in JSPs.


 Cars Example
 

Created by:  Brandan Jones January 4, 2002