| /* |
| * 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.search; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Objects; |
| import java.util.stream.Collectors; |
| import java.util.stream.StreamSupport; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.util.BytesRefIterator; |
| import org.apache.lucene.util.IOSupplier; |
| |
| /** |
| * Contains static functions that aid the implementation of {@link Matches} and |
| * {@link MatchesIterator} interfaces. |
| */ |
| public final class MatchesUtils { |
| |
| private MatchesUtils() {} // static functions only |
| |
| /** |
| * Indicates a match with no term positions, for example on a Point or DocValues field, |
| * or a field indexed as docs and freqs only |
| */ |
| public static final Matches MATCH_WITH_NO_TERMS = new Matches() { |
| @Override |
| public MatchesIterator getMatches(String field) { |
| return null; |
| } |
| |
| @Override |
| public Collection<Matches> getSubMatches() { |
| return Collections.emptyList(); |
| } |
| |
| @Override |
| public Iterator<String> iterator() { |
| return Collections.emptyIterator(); |
| } |
| }; |
| |
| /** |
| * Amalgamate a collection of {@link Matches} into a single object |
| */ |
| public static Matches fromSubMatches(List<Matches> subMatches) { |
| if (subMatches == null || subMatches.size() == 0) { |
| return null; |
| } |
| List<Matches> sm = subMatches.stream().filter(m -> m != MATCH_WITH_NO_TERMS).collect(Collectors.toList()); |
| if (sm.size() == 0) { |
| return MATCH_WITH_NO_TERMS; |
| } |
| if (sm.size() == 1) { |
| return sm.get(0); |
| } |
| |
| return new Matches() { |
| @Override |
| public MatchesIterator getMatches(String field) throws IOException { |
| List<MatchesIterator> subIterators = new ArrayList<>(sm.size()); |
| for (Matches m : sm) { |
| MatchesIterator it = m.getMatches(field); |
| if (it != null) { |
| subIterators.add(it); |
| } |
| } |
| return DisjunctionMatchesIterator.fromSubIterators(subIterators); |
| } |
| |
| @Override |
| public Iterator<String> iterator() { |
| // for each sub-match, iterate its fields (it's an Iterable of the fields), and return the distinct set |
| return sm.stream().flatMap(m -> StreamSupport.stream(m.spliterator(), false)).distinct().iterator(); |
| } |
| |
| @Override |
| public Collection<Matches> getSubMatches() { |
| return subMatches; |
| } |
| }; |
| } |
| |
| /** |
| * Create a Matches for a single field |
| */ |
| public static Matches forField(String field, IOSupplier<MatchesIterator> mis) throws IOException { |
| |
| // The indirection here, using a Supplier object rather than a MatchesIterator |
| // directly, is to allow for multiple calls to Matches.getMatches() to return |
| // new iterators. We still need to call MatchesIteratorSupplier.get() eagerly |
| // to work out if we have a hit or not. |
| |
| MatchesIterator mi = mis.get(); |
| if (mi == null) { |
| return null; |
| } |
| return new Matches() { |
| boolean cached = true; |
| @Override |
| public MatchesIterator getMatches(String f) throws IOException { |
| if (Objects.equals(field, f) == false) { |
| return null; |
| } |
| if (cached == false) { |
| return mis.get(); |
| } |
| cached = false; |
| return mi; |
| } |
| |
| @Override |
| public Iterator<String> iterator() { |
| return Collections.singleton(field).iterator(); |
| } |
| |
| @Override |
| public Collection<Matches> getSubMatches() { |
| return Collections.emptyList(); |
| } |
| }; |
| } |
| |
| /** |
| * Create a MatchesIterator that iterates in order over all matches in a set of subiterators |
| */ |
| public static MatchesIterator disjunction(List<MatchesIterator> subMatches) throws IOException { |
| return DisjunctionMatchesIterator.fromSubIterators(subMatches); |
| } |
| |
| /** |
| * Create a MatchesIterator that is a disjunction over a list of terms extracted from a {@link BytesRefIterator}. |
| * |
| * Only terms that have at least one match in the given document will be included |
| */ |
| public static MatchesIterator disjunction(LeafReaderContext context, int doc, Query query, String field, BytesRefIterator terms) throws IOException { |
| return DisjunctionMatchesIterator.fromTermsEnum(context, doc, query, field, terms); |
| } |
| } |