(CR#6553074) Unnecessary array copy in AbstractStringBuilder.indexOf(String)? (original) (raw)

Mike Duigou mike.duigou at oracle.com
Mon Nov 19 17:49:22 UTC 2012

By amazing coincidence a review for fixing this was issued last week:

http://mail.openjdk.java.net/pipermail/core-libs-dev/2012-November/012266.html

Additional review would be welcome. :-)

The patch will probably be ready for push before the end of the month.

Mike

On Nov 19 2012, at 07:46 , Martin Desruisseaux wrote:

Hello all

I noticed that AbstractStringBuilder.indexOf(String, int) is implemented as below: public int indexOf(String str, int fromIndex) { return String.indexOf(value, 0, count, str.toCharArray(), 0, str.length(), fromIndex); } The call to str.toCharArray() creates a copy of the String.value char[] array. This copy doesn't seem necessary since the above String.indexOf(...) method doesn't modify the array content. Shouldn't AbstractStringBuilder passes directly the reference to the String internal array instead, maybe using package-privated access to the array? Admittedly the cloned array is usually small, but the call to indexOf(String, int) is often done in a loop. Martin

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