On Fri, 15 Oct 1999, Robert Simmons wrote:
>
> ----- Original Message -----
> From: Gordon Keith <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Cc: Robert Simmons <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
> Sent: Wednesday, October 13, 1999 8:36 PM
> Subject: Re: Const in java
>
>
> > [EMAIL PROTECTED] wrote:
> > >
> > > On Wed, 13 Oct 1999, Robert Simmons wrote:
> > >
> > > > Since everything in java is passed by reference this becomes even more
> of an issue.
> > > > Therefore can I do the following to achieve the desired safety ?
> > >
> > > Well, everything is not passed by reference in Java. I believe
> primitives
> > > and immutable types are passed by value. Someone know the exact rules
> > > behind this?
> >
> > Everything is passed by value.
> > But you never actually pass objects, you only ever pass references to
> > objects.
> >
> > Making a parameter final means you can't change what object that
> > parameter refers to. (you can still make changes to the object, if it's
> > not immutable)
>
> Such is the problem there are times where I dont want the user to be able
> to alter a returned object's state.
>
That's easy enough to get around. All you do is clone the object before you
give it back to them. All java Objects should have a clone() function since
that's part of the Object class. That is unless I'm misunderstanding what the
clone() function does, which I wouldn't put past me.
> >
> > Once you understand that its pretty clear what's happening.
> >
> > Regards
> > Gordon
> >
> >
> > Gordon Keith
> > Programmer
> > Marine Science Support
> > Australian Antarctic Divsion
> > http://www.antdiv.gov.au
> >
>
>
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