| /* |
| * 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.solr.search; |
| |
| import java.io.IOException; |
| import java.util.Set; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.Term; |
| import org.apache.lucene.search.ConstantScoreScorer; |
| import org.apache.lucene.search.DocIdSet; |
| 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.TwoPhaseIterator; |
| import org.apache.lucene.search.Weight; |
| import org.apache.lucene.util.Bits; |
| |
| /** |
| * Convenient base class for building queries that only perform matching, but |
| * no scoring. The scorer produced by such queries always returns 0 as score. |
| */ |
| public abstract class Filter extends Query { |
| |
| private final boolean applyLazily; |
| |
| /** Filter constructor. When {@code applyLazily} is true and the produced |
| * {@link DocIdSet}s support {@link DocIdSet#bits() random-access}, Lucene |
| * will only apply this filter after other clauses. */ |
| protected Filter(boolean applyLazily) { |
| this.applyLazily = applyLazily; |
| } |
| |
| /** Default Filter constructor that will use the |
| * {@link DocIdSet#iterator() doc id set iterator} when consumed through |
| * the {@link Query} API. */ |
| protected Filter() { |
| this(false); |
| } |
| |
| /** |
| * Creates a {@link DocIdSet} enumerating the documents that should be |
| * permitted in search results. <b>NOTE:</b> null can be |
| * returned if no documents are accepted by this Filter. |
| * <p> |
| * Note: This method will be called once per segment in |
| * the index during searching. The returned {@link DocIdSet} |
| * must refer to document IDs for that segment, not for |
| * the top-level reader. |
| * |
| * @param context a {@link org.apache.lucene.index.LeafReaderContext} instance opened on the index currently |
| * searched on. Note, it is likely that the provided reader info does not |
| * represent the whole underlying index i.e. if the index has more than |
| * one segment the given reader only represents a single segment. |
| * The provided context is always an atomic context, so you can call |
| * {@link org.apache.lucene.index.LeafReader#terms(String)} |
| * on the context's reader, for example. |
| * |
| * @param acceptDocs |
| * Bits that represent the allowable docs to match (typically deleted docs |
| * but possibly filtering other documents) |
| * |
| * @return a DocIdSet that provides the documents which should be permitted or |
| * prohibited in search results. <b>NOTE:</b> <code>null</code> should be returned if |
| * the filter doesn't accept any documents otherwise internal optimization might not apply |
| * in the case an <i>empty</i> {@link DocIdSet} is returned. |
| */ |
| public abstract DocIdSet getDocIdSet(LeafReaderContext context, Bits acceptDocs) throws IOException; |
| |
| // |
| // Query compatibility |
| // |
| |
| @Override |
| public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) { |
| return new Weight(this) { |
| |
| @Override |
| public void extractTerms(Set<Term> terms) {} |
| |
| @Override |
| public Explanation explain(LeafReaderContext context, int doc) throws IOException { |
| final Scorer scorer = scorer(context); |
| final boolean match = (scorer != null && scorer.iterator().advance(doc) == doc); |
| if (match) { |
| assert scorer.score() == 0f; |
| return Explanation.match(0f, "Match on id " + doc); |
| } else { |
| return Explanation.match(0f, "No match on id " + doc); |
| } |
| } |
| |
| @Override |
| public Scorer scorer(LeafReaderContext context) throws IOException { |
| final DocIdSet set = getDocIdSet(context, null); |
| if (set == null) { |
| return null; |
| } |
| if (applyLazily && set.bits() != null) { |
| final Bits bits = set.bits(); |
| final DocIdSetIterator approximation = DocIdSetIterator.all(context.reader().maxDoc()); |
| final TwoPhaseIterator twoPhase = new TwoPhaseIterator(approximation) { |
| @Override |
| public boolean matches() throws IOException { |
| return bits.get(approximation.docID()); |
| } |
| |
| @Override |
| public float matchCost() { |
| return 10; // TODO use cost of bits.get() |
| } |
| }; |
| return new ConstantScoreScorer(this, 0f, scoreMode, twoPhase); |
| } |
| final DocIdSetIterator iterator = set.iterator(); |
| if (iterator == null) { |
| return null; |
| } |
| return new ConstantScoreScorer(this, 0f, scoreMode, iterator); |
| } |
| |
| @Override |
| public boolean isCacheable(LeafReaderContext ctx) { |
| return false; |
| } |
| }; |
| } |
| |
| @Override |
| public void visit(QueryVisitor visitor) { |
| visitor.visitLeaf(this); |
| } |
| } |