2011-07-04 groupingメモ lucene このあたり http://lucene.apache.org/java/3_2_0/api/contrib-grouping/org/apache/lucene/search/grouping/AllGroupsCollector.htmlテストがこのあたり http://svn.apache.org/viewvc/lucene/dev/branches/lucene_solr_3_3/lucene/contrib/grouping/src/test/org/apache/lucene/search/grouping/TestGrouping.java?view=markup