| /* |
| * 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. |
| */ |
| package org.apache.lucene.queries.function; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import org.apache.lucene.index.IndexReader; |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.Term; |
| import org.apache.lucene.search.DocIdSetIterator; |
| import org.apache.lucene.search.Explanation; |
| import org.apache.lucene.search.IndexSearcher; |
| import org.apache.lucene.search.Query; |
| import org.apache.lucene.search.QueryVisitor; |
| import org.apache.lucene.search.ScoreMode; |
| import org.apache.lucene.search.Scorer; |
| import org.apache.lucene.search.Weight; |
| |
| |
| /** |
| * Returns a score for each document based on a ValueSource, |
| * often some function of the value of a field. |
| * |
| * @see ValueSourceScorer |
| * @lucene.experimental |
| */ |
| public class FunctionQuery extends Query { |
| final ValueSource func; |
| |
| /** |
| * @param func defines the function to be used for scoring |
| */ |
| public FunctionQuery(ValueSource func) { |
| this.func=func; |
| } |
| |
| /** @return The associated ValueSource */ |
| public ValueSource getValueSource() { |
| return func; |
| } |
| |
| protected class FunctionWeight extends Weight { |
| protected final IndexSearcher searcher; |
| protected final float boost; |
| protected final Map context; |
| |
| public FunctionWeight(IndexSearcher searcher, float boost) throws IOException { |
| super(FunctionQuery.this); |
| this.searcher = searcher; |
| this.context = ValueSource.newContext(searcher); |
| func.createWeight(context, searcher); |
| this.boost = boost; |
| } |
| |
| @Override |
| public void extractTerms(Set<Term> terms) {} |
| |
| @Override |
| public Scorer scorer(LeafReaderContext context) throws IOException { |
| return new AllScorer(context, this, boost); |
| } |
| |
| @Override |
| public boolean isCacheable(LeafReaderContext ctx) { |
| return false; |
| } |
| |
| @Override |
| public Explanation explain(LeafReaderContext context, int doc) throws IOException { |
| return ((AllScorer)scorer(context)).explain(doc); |
| } |
| } |
| |
| @Override |
| public void visit(QueryVisitor visitor) { |
| visitor.visitLeaf(this); |
| } |
| |
| protected class AllScorer extends Scorer { |
| final IndexReader reader; |
| final FunctionWeight weight; |
| final int maxDoc; |
| final float boost; |
| final DocIdSetIterator iterator; |
| final FunctionValues vals; |
| |
| public AllScorer(LeafReaderContext context, FunctionWeight w, float boost) throws IOException { |
| super(w); |
| this.weight = w; |
| this.boost = boost; |
| this.reader = context.reader(); |
| this.maxDoc = reader.maxDoc(); |
| iterator = DocIdSetIterator.all(context.reader().maxDoc()); |
| vals = func.getValues(weight.context, context); |
| } |
| |
| @Override |
| public DocIdSetIterator iterator() { |
| return iterator; |
| } |
| |
| @Override |
| public int docID() { |
| return iterator.docID(); |
| } |
| |
| @Override |
| public float score() throws IOException { |
| float val = vals.floatVal(docID()); |
| if (val >= 0 == false) { // this covers NaN as well since comparisons with NaN return false |
| return 0; |
| } else { |
| return boost * val; |
| } |
| } |
| |
| @Override |
| public float getMaxScore(int upTo) throws IOException { |
| return Float.POSITIVE_INFINITY; |
| } |
| |
| public Explanation explain(int doc) throws IOException { |
| Explanation expl = vals.explain(doc); |
| if (expl.getValue().floatValue() < 0) { |
| expl = Explanation.match(0, "truncated score, max of:", Explanation.match(0f, "minimum score"), expl); |
| } else if (Float.isNaN(expl.getValue().floatValue())) { |
| expl = Explanation.match(0, "score, computed as (score == NaN ? 0 : score) since NaN is an illegal score from:", expl); |
| } |
| |
| return Explanation.match(boost * expl.getValue().floatValue(), "FunctionQuery(" + func + "), product of:", |
| vals.explain(doc), |
| Explanation.match(weight.boost, "boost")); |
| } |
| |
| } |
| |
| |
| @Override |
| public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException { |
| return new FunctionQuery.FunctionWeight(searcher, boost); |
| } |
| |
| /** Prints a user-readable version of this query. */ |
| @Override |
| public String toString(String field) |
| { |
| return func.toString(); |
| } |
| |
| |
| /** Returns true if <code>o</code> is equal to this. */ |
| @Override |
| public boolean equals(Object other) { |
| return sameClassAs(other) && |
| func.equals(((FunctionQuery) other).func); |
| } |
| |
| @Override |
| public int hashCode() { |
| return classHash() ^ func.hashCode(); |
| } |
| } |