Re: Unnecessary array allocation and copying

[Sylvain Wallez]

Ugo Cei wrote:

While browsing our sources, I came across this snippet from 
o.a.c..components.pipeline.AbstractProcessingPipeline:

                    // execute the pipeline:
                    this.generator.generate();
                    byte[] data = os.toByteArray();
                    environment.setContentLength(data.length);
                    environment.getOutputStream(0).write(data);
But from the javadocs of java.io.ByteArrayOutputStream#toByteArray, I 
read:

"Creates a newly allocated byte array. Its size is the current size of 
this output stream and the valid contents of the buffer have been 
copied into it."

Thus I wonder: why are we doing this copy instead of doing:

                    // execute the pipeline:
                    this.generator.generate();
                    environment.setContentLength(os.size());
                    os.writeTo(environment.getOutputStream(0));
If I'm not mistaken, this would avoid allocating and copying an array 
as large as the serializer's output. Or am I missing something subtle 
here?


I guess you just found a more efficient way to achieve exactly the same 
thing ;-)

It seems to me we can safely avoid this array allocation.

Sylvain

--
Sylvain Wallez                                  Anyware Technologies
http://www.apache.org/~sylvain           http://www.anyware-tech.com
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