Macromedia flex 2-migrating applications to flex 2 Manual De Usuario

Classes and packages

27

Using classes

This section describes changes to ActionScript classes.

Access modifiers

The new 

internal

 access modifier refers to a different namespace in each package definition, 

and is not defined outside of a package definition (that is, in global code).

If a class in a package isn’t marked 

public

 or 

private

, then it defaults to 

internal

. The class 

cannot be accessed by classes in other packages; this is the same as the 

protected

 modifier in 

Java. Accessing internal classes from outside of the package causes a ReferenceError at run 
time. 

If you do not put any namespace (public, private, internal, or user-defined) on a declaration, 
the Flex compiler throws a warning. 

The following table summarizes the access modifiers:

Inside a package, the default access specifier is 

internal

. Outside of a package, the default 

access specifier is 

public

.

Class identifiers

The form ClassIdentifiers:ClassIdentifiers.Identifier has been deprecated and results in a 
compile-time warning. It is equivalent to declaring the class name Identifier in the package 
ClassIdentifiers. For example:

class P.A {}

// ActionScript 2.0

package P {

// ActionScript 3.0

    class A {}
}

super()

You can only use a 

super()

 statement inside a constructor. It is a syntax error to use a 

super()

 statement anywhere else in a program. Previous versions of ActionScript allowed 

super()

 statements to be used anywhere in a class (except in a static method).

Access Modifier

Description

private

Only accessible to the class.

public

Accessible from anywhere.

protected

Private to classes and subclasses.

internal

Private to other classes in the package.