Mark Miller wrote:
Grant Ingersoll wrote:
On Aug 3, 2009, at 8:21 PM, Mark Miller wrote:
4. You cannot instantiate MergePolicy with a no arg constructor
anymore - so that fails now. I don't have a fix for this at the moment.
That sounds like a back compat break ;-)
It was - but they knew it would be and decided it was fine. The
methods on the class were package private, so it appeared reasonable.
The class was also labeled as expert and subject to sudden change. I
guess it was fair game to break - I don't think this scenario was
thought of, but I would think we can work around it. I havn't really
thought about it yet myself though.
So this is a bit tricky I guess. The way they handled this in Lucene
Benchmark is:
writer.setMergePolicy((MergePolicy)
Class.forName(mergePolicy).getConstructor(new Class[] {
IndexWriter.class }).newInstance(new Object[] { writer }));
Now if we handle it the same way, thats fine. But then you can't put one
of these in solr.home/lib. To do that, you have to use
SolrResourceLoader.newInstance - which requires a no arg constructor. I
think we can do something like: create an object with SolrResourceLoader
that loads the MergePolicy - it can use Class.forName like above because
it will use the Classloader of the object that invoked it. But I'd
rather not go there if we don't have to. This is a pretty advanced
plugin, and likely just intended for picking between included Lucene
impls. Do we want to make sure it can still be loaded from solr.home/lib?
--
- Mark
http://www.lucidimagination.com
