Review

class DisjunctionMaxQuery.DisjunctionMaxWeight {
    /* Explain the score we computed for doc */
    public Explanation explain(IndexReader reader, int doc) throws IOException {
      if (disjuncts.size() == 1) return ((Weight) weights.get(0)).explain(reader,doc);
      ComplexExplanation result = new ComplexExplanation();
      float max = 0.0f, sum = 0.0f;
      result.setDescription(tieBreakerMultiplier == 0.0f ? "max of:" : "max plus " + tieBreakerMultiplier + " times others of:");
      for (Iterator iter = weights.iterator(); iter.hasNext();) {
        Explanation e = ((Weight) iter.next()).explain(reader, doc);
        if (e.isMatch()) {
          result.setMatch(Boolean.TRUE);
          result.addDetail(e);
          sum += e.getValue();
          max = Math.max(max, e.getValue());
        }
      }
      result.setValue(max + (sum - max) * tieBreakerMultiplier);
      return result;
    }

}