Update Field on Many Docs

[Matt Hicks]

I'm trying to write an efficient update to match with a Query and update all
matches with specific fields (while maintaining the other previously set fields
on each document).  I see IndexWriter.updateDocValues appears to be the closest
solution, but it takes a Term and I'd prefer to use a Query.  Is there any way
to accomplish this in Lucene without querying and updating each entry manually?