XOM API for Processing XML with Java

[Wolfgang Hoschek <whoschek AT lbl.gov>]

On Jul 21, 2005, at 9:30 AM, Elliotte Harold wrote:

> Wolfgang Hoschek wrote:
>
>
> > 2. replace BufferedWriter used by Serializer with an  
> > unsynchronized  custom version, enabling much better compiler  
> > inlining
>
> I've confirmed this. It's a noticeable improvement. A version of  
> this is now in CVS. It's a bit of a surprise. I thought  
> synchronization wasn't supposed to have such a huge impact in  
> modern VMs.
>
> I experimented with several variations but I ended up committing  
> basically what Wolfgang submitted modulo some refinements to fit my  
> coding conventions that I don't think have any impact on the byte  
> code. I'll look at the other changes as time permits. Thanks!

You also want to want to declare "out" a non-polymorphic variable in  
TextWriter.

private final UnsynchronizedBufferedWriter out;

This greatly eases the inlining burden on the compiler for all those  
many places where out.write(char) is called, because  
UnsynchronizedBufferedWriter is known to be final.

The clean way of doing it is using that as a type in all TextWriter  
constructors and their subclasses. If there should ever be a need for  
some other form of writer you could change it back to a generic  
"Writer" type. The cast I used was so that I didn't have to change  
all the TextWriter subclasses.

Wolfgang.