Re: What's the use of private?

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 17 Feb 2008 10:43:42 -0800

Message-ID:

<fp9v8v$1q50$1@ihnp4.ucsd.edu>

Wojtek wrote:

Jeff.M wrote :

Unless I'm mistaken, private things are inaccessible to everything
else, even subclasses. And it seems that using private makes it
difficult, if not impossible, to extend the class. Protected, on the
other hand, is just like private except that extending classes can use
protected things.

But you can access the super class private variables. Just use the
public accessors (getX, setX). Or maybe protected accessors. At any rate
the variable is private and cannot be accessed directly (encapsulation).

BTW, most modern compilers will see that if a get/set simply accesses
the private variable with no computation, then it maps it directly, so
there are no performance issues.

If public or protected get/set methods are provided for fields without
thought, there is no maintainability gain and the fields might as well
have had the access permission of the methods. Using get/set is only an
advantage if they relate to logical attributes that are unlikely to
change even if the superclass implementation changes.

Patricia