Java tutorial
/* * 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.valuesource; import java.io.IOException; import java.util.Map; import org.apache.lucene.index.LeafReaderContext; import org.apache.lucene.index.ReaderUtil; import org.apache.lucene.queries.function.FunctionValues; import org.apache.lucene.queries.function.ValueSource; import org.apache.lucene.queries.function.docvalues.FloatDocValues; import org.apache.lucene.search.DocIdSetIterator; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.Query; import org.apache.lucene.search.ScoreMode; import org.apache.lucene.search.Scorer; import org.apache.lucene.search.Weight; import org.apache.lucene.util.mutable.MutableValue; import org.apache.lucene.util.mutable.MutableValueFloat; /** * <code>QueryValueSource</code> returns the relevance score of the query */ public class QueryValueSource extends ValueSource { final Query q; final float defVal; public QueryValueSource(Query q, float defVal) { this.q = q; this.defVal = defVal; } public Query getQuery() { return q; } public float getDefaultValue() { return defVal; } @Override public String description() { return "query(" + q + ",def=" + defVal + ")"; } @Override public FunctionValues getValues(Map fcontext, LeafReaderContext readerContext) throws IOException { return new QueryDocValues(this, readerContext, fcontext); } @Override public int hashCode() { return q.hashCode() * 29; } @Override public boolean equals(Object o) { if (QueryValueSource.class != o.getClass()) return false; QueryValueSource other = (QueryValueSource) o; return this.q.equals(other.q) && this.defVal == other.defVal; } @Override public void createWeight(Map context, IndexSearcher searcher) throws IOException { Query rewritten = searcher.rewrite(q); Weight w = searcher.createWeight(rewritten, ScoreMode.COMPLETE, 1); context.put(this, w); } } class QueryDocValues extends FloatDocValues { final LeafReaderContext readerContext; final Weight weight; final float defVal; final Map fcontext; final Query q; Scorer scorer; DocIdSetIterator it; int scorerDoc; // the document the scorer is on boolean noMatches = false; // the last document requested... start off with high value // to trigger a scorer reset on first access. int lastDocRequested = Integer.MAX_VALUE; public QueryDocValues(QueryValueSource vs, LeafReaderContext readerContext, Map fcontext) throws IOException { super(vs); this.readerContext = readerContext; this.defVal = vs.defVal; this.q = vs.q; this.fcontext = fcontext; Weight w = fcontext == null ? null : (Weight) fcontext.get(vs); if (w == null) { IndexSearcher weightSearcher; if (fcontext == null) { weightSearcher = new IndexSearcher(ReaderUtil.getTopLevelContext(readerContext)); } else { weightSearcher = (IndexSearcher) fcontext.get("searcher"); if (weightSearcher == null) { weightSearcher = new IndexSearcher(ReaderUtil.getTopLevelContext(readerContext)); } } vs.createWeight(fcontext, weightSearcher); w = (Weight) fcontext.get(vs); } weight = w; } @Override public float floatVal(int doc) { try { if (doc < lastDocRequested) { if (noMatches) return defVal; scorer = weight.scorer(readerContext); if (scorer == null) { noMatches = true; return defVal; } it = scorer.iterator(); scorerDoc = -1; } lastDocRequested = doc; if (scorerDoc < doc) { scorerDoc = it.advance(doc); } if (scorerDoc > doc) { // query doesn't match this document... either because we hit the // end, or because the next doc is after this doc. return defVal; } // a match! return scorer.score(); } catch (IOException e) { throw new RuntimeException("caught exception in QueryDocVals(" + q + ") doc=" + doc, e); } } @Override public boolean exists(int doc) { try { if (doc < lastDocRequested) { if (noMatches) return false; scorer = weight.scorer(readerContext); scorerDoc = -1; if (scorer == null) { noMatches = true; return false; } it = scorer.iterator(); } lastDocRequested = doc; if (scorerDoc < doc) { scorerDoc = it.advance(doc); } if (scorerDoc > doc) { // query doesn't match this document... either because we hit the // end, or because the next doc is after this doc. return false; } // a match! return true; } catch (IOException e) { throw new RuntimeException("caught exception in QueryDocVals(" + q + ") doc=" + doc, e); } } @Override public Object objectVal(int doc) { try { return exists(doc) ? scorer.score() : null; } catch (IOException e) { throw new RuntimeException("caught exception in QueryDocVals(" + q + ") doc=" + doc, e); } } @Override public ValueFiller getValueFiller() { // // TODO: if we want to support more than one value-filler or a value-filler in conjunction with // the FunctionValues, then members like "scorer" should be per ValueFiller instance. // Or we can say that the user should just instantiate multiple FunctionValues. // return new ValueFiller() { private final MutableValueFloat mval = new MutableValueFloat(); @Override public MutableValue getValue() { return mval; } @Override public void fillValue(int doc) { try { if (noMatches) { mval.value = defVal; mval.exists = false; return; } scorer = weight.scorer(readerContext); scorerDoc = -1; if (scorer == null) { noMatches = true; mval.value = defVal; mval.exists = false; return; } it = scorer.iterator(); lastDocRequested = doc; if (scorerDoc < doc) { scorerDoc = it.advance(doc); } if (scorerDoc > doc) { // query doesn't match this document... either because we hit the // end, or because the next doc is after this doc. mval.value = defVal; mval.exists = false; return; } // a match! mval.value = scorer.score(); mval.exists = true; } catch (IOException e) { throw new RuntimeException("caught exception in QueryDocVals(" + q + ") doc=" + doc, e); } } }; } @Override public String toString(int doc) { return "query(" + q + ",def=" + defVal + ")=" + floatVal(doc); } }