Java: Methods

Methods, procedures, functions, subroutines are all basically the same, a chunk of code that does one small task. In Java, each method must be defined in a class.

A method is always followed by a pair of parentheses (). The parentheses may contain parameters or my be left empty if there are no parameters.

Scope of Methods:

    • private - can not be used outside of the class it is contained in
    • public - can be used by other classes

Return Type

    • void -- no data returned
    • return data type

Method Parameters

    • the list in parenthesis including the data type and local name
    • if there are no parameters, the parenthesis are left empty.

Method Signature

Types of methods:

    • setters: are used to set the value of an instance field. These types of methods are also known as mutators. A mutator changes (or sets) the value of a variable.
    • getters: are used to get the value of an instance field. Used to allow other objects to get the value of a variable.
    • constructors: used to create an instance of a object.
      • must have the same name as the class it constructs
      • the return type is not part of the method header
    • behaviors: methods that make the object take action. These allow other objects to ask this object to perform an action. "Tell, don't ask"

Naming a method

    • verb or action phrase that describes the action the method will do