| package org.apache.lucene.search.spans; |
| |
| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.search.Explanation; |
| import org.apache.lucene.search.Weight; |
| import org.apache.lucene.search.Scorer; |
| import org.apache.lucene.search.Similarity; |
| |
| /** |
| * Public for extension only. |
| */ |
| public class SpanScorer extends Scorer { |
| protected Spans spans; |
| protected Weight weight; |
| protected byte[] norms; |
| protected float value; |
| |
| protected boolean more = true; |
| |
| protected int doc; |
| protected float freq; |
| |
| protected SpanScorer(Spans spans, Weight weight, Similarity similarity, byte[] norms) |
| throws IOException { |
| super(similarity); |
| this.spans = spans; |
| this.norms = norms; |
| this.weight = weight; |
| this.value = weight.getValue(); |
| if (this.spans.next()) { |
| doc = -1; |
| } else { |
| doc = NO_MORE_DOCS; |
| more = false; |
| } |
| } |
| |
| @Override |
| public int nextDoc() throws IOException { |
| if (!setFreqCurrentDoc()) { |
| doc = NO_MORE_DOCS; |
| } |
| return doc; |
| } |
| |
| @Override |
| public int advance(int target) throws IOException { |
| if (!more) { |
| return doc = NO_MORE_DOCS; |
| } |
| if (spans.doc() < target) { // setFreqCurrentDoc() leaves spans.doc() ahead |
| more = spans.skipTo(target); |
| } |
| if (!setFreqCurrentDoc()) { |
| doc = NO_MORE_DOCS; |
| } |
| return doc; |
| } |
| |
| protected boolean setFreqCurrentDoc() throws IOException { |
| if (!more) { |
| return false; |
| } |
| doc = spans.doc(); |
| freq = 0.0f; |
| do { |
| int matchLength = spans.end() - spans.start(); |
| freq += getSimilarity().sloppyFreq(matchLength); |
| more = spans.next(); |
| } while (more && (doc == spans.doc())); |
| return true; |
| } |
| |
| @Override |
| public int docID() { return doc; } |
| |
| @Override |
| public float score() throws IOException { |
| float raw = getSimilarity().tf(freq) * value; // raw score |
| return norms == null? raw : raw * Similarity.decodeNorm(norms[doc]); // normalize |
| } |
| |
| /** This method is no longer an official member of {@link Scorer}, |
| * but it is needed by SpanWeight to build an explanation. */ |
| protected Explanation explain(final int doc) throws IOException { |
| Explanation tfExplanation = new Explanation(); |
| |
| int expDoc = advance(doc); |
| |
| float phraseFreq = (expDoc == doc) ? freq : 0.0f; |
| tfExplanation.setValue(getSimilarity().tf(phraseFreq)); |
| tfExplanation.setDescription("tf(phraseFreq=" + phraseFreq + ")"); |
| |
| return tfExplanation; |
| } |
| |
| } |