Review

class MatchAllDocsQuery.MatchAllDocsWeight {
    public Explanation explain(IndexReader reader, int doc) {
      // explain query weight
      Explanation queryExpl = new ComplexExplanation
        (true, getValue(), "MatchAllDocsQuery, product of:");
      if (getBoost() != 1.0f) {
        queryExpl.addDetail(new Explanation(getBoost(),"boost"));
      }
      queryExpl.addDetail(new Explanation(queryNorm,"queryNorm"));

      return queryExpl;
    }

}