On Thu, 9 Jan 2003, Stephan Michels wrote:
>
>
> On Thu, 9 Jan 2003, Giacomo Pati wrote:
>
> > On Thu, 9 Jan 2003, Stephan Michels wrote:
> >
> > >
> > >
> > >
> > > On 9 Jan 2003 [EMAIL PROTECTED] wrote:
> > >
> > > > giacomo 2003/01/09 06:35:25
> > > >
> > > > Modified: src/scratchpad/src/org/apache/cocoon/components/source/impl
> > > > SlideSource.java
> > > > Log:
> > > > make some method package protected instead of privat to increase performance
>by avoiding 'access emulated by a synthetic accessor method' (objected by eclipse)
> > > >
> > >
> > >
> > > Hmm, do really think that using package protected modifiers instead of
> > > private modifiers make the implementation faster. For some time I read
> > > an article, which says the private modifier make the fastest access
> > > possible.
> >
> > You can prove that by yourself using the following code:
> >
> > public class A
> > {
> > private int a;
> >
> > public A()
> > {
> > AA aa = new AA();
> > }
> >
> > private int foo( AA a )
> > {
> > AA b = a;
> > return 0;
> > }
> >
> > public class AA
> > {
> > public AA()
> > {
> > int b = a;
> > }
> > public void b()
> > {
> > foo( this );
> > }
> > }
> > }
> >
> > Compile this and produce an assembly listing (javap -c A).
> >
> > Now, remove the private modifier from the 'int a' as well as from method
> > foo to make it package protected.
> >
> > If you compare these assably listing you'll see what java does with it.
> >
> > Access to the private variable 'a' as well as to the private method
> > 'foo' from within the inner class is indirected by use of
> > a synthetic accessor method.
>
> Okay, now I see what you mean, because of the inner class
> SlideSourceOutputStream the accessor methods will be produced. And
> now Eclipse thinks that if I change all used member variables to
> package private all run faster.
>
> If you insert
>
> private int bar()
> {
> return a+3;
> }
>
> you will see that bar doesn't need a synthetic accessor method.
Of course not, it's in the same instance.
> So have a bit more Performance, with a package private member variables.
>
> First rule of performance tuning: Don't do it. cit. Bitter Java(I think)
or better 'don't access private outer class methods/variables from inner
classes'.
Ok, does any other here have an oppinion on this?
Giacomo
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