Wednesday, October 22, 2014

Method Modifiers

There are several modifiers that can be applied to method declarations.

Public: Methods that are declared as public are accessible anywhere the class is accessible and can be overridden by subclasses. Methods that have no access modifier are implicitly public.

Private: Methods that are declared as private can be called only from methods in the class where the private method is declared.

Protected: Methods that are declared as protected can only be called from methods in the class and in subclasses that extend the class where the method is declared.

final: Indicates that the method cannot be overridden in any class that derives from its class.

Server: Establishes the location where the method is to be executed (on the server).
Can only be used on static methods. If the method is not static, you need to specify the location using the class property RunOn.

Client: Establishes the location where the method is to be executed (on the client).
Can only be used on static methods. If the method is not static, specify the location by using the class property RunOn.

abstract : The method is declared but not implemented in a parent class. The method must be overridden in subclasses.
If you try to create an object from a subclass where one or more of the abstract methods belonging to the parent class have not been overridden, you will get a compiler error.
Ex: SalesFormLetter

static: Specifies that the method is a class method and does not operate on an object.
static methods cannot refer to instance variables and are invoked by using the class name rather than on an instance of the class (MyClass::aStaticProcedure()).

Display: Indicates that the method's return value is to be displayed on a form or a report. The value cannot be altered in the form or report. The return value is typically a calculated value,
for example, a sum.

edit: Indicates that the method's return type is to be used to provide information for a field that is used in a form. The value in the field can be edited.

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