| /* |
| * 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 org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.IndexReader; |
| import org.apache.lucene.index.IndexReaderContext; |
| import org.apache.lucene.index.Term; |
| import org.apache.lucene.index.TermStates; |
| import org.apache.lucene.index.Terms; |
| import org.apache.lucene.index.TermsEnum; |
| import org.apache.lucene.util.AttributeSource; |
| import org.apache.lucene.util.BytesRef; |
| |
| abstract class TermCollectingRewrite<B> extends MultiTermQuery.RewriteMethod { |
| |
| |
| /** Return a suitable builder for the top-level Query for holding all expanded terms. */ |
| protected abstract B getTopLevelBuilder() throws IOException; |
| |
| /** Finalize the creation of the query from the builder. */ |
| protected abstract Query build(B builder); |
| |
| /** Add a MultiTermQuery term to the top-level query builder. */ |
| protected final void addClause(B topLevel, Term term, int docCount, float boost) throws IOException { |
| addClause(topLevel, term, docCount, boost, null); |
| } |
| |
| protected abstract void addClause(B topLevel, Term term, int docCount, float boost, TermStates states) throws IOException; |
| |
| |
| final void collectTerms(IndexReader reader, MultiTermQuery query, TermCollector collector) throws IOException { |
| IndexReaderContext topReaderContext = reader.getContext(); |
| for (LeafReaderContext context : topReaderContext.leaves()) { |
| final Terms terms = context.reader().terms(query.field); |
| if (terms == null) { |
| // field does not exist |
| continue; |
| } |
| |
| final TermsEnum termsEnum = getTermsEnum(query, terms, collector.attributes); |
| assert termsEnum != null; |
| |
| if (termsEnum == TermsEnum.EMPTY) |
| continue; |
| |
| collector.setReaderContext(topReaderContext, context); |
| collector.setNextEnum(termsEnum); |
| BytesRef bytes; |
| while ((bytes = termsEnum.next()) != null) { |
| if (!collector.collect(bytes)) |
| return; // interrupt whole term collection, so also don't iterate other subReaders |
| } |
| } |
| } |
| |
| static abstract class TermCollector { |
| |
| protected LeafReaderContext readerContext; |
| protected IndexReaderContext topReaderContext; |
| |
| public void setReaderContext(IndexReaderContext topReaderContext, LeafReaderContext readerContext) { |
| this.readerContext = readerContext; |
| this.topReaderContext = topReaderContext; |
| } |
| /** attributes used for communication with the enum */ |
| public final AttributeSource attributes = new AttributeSource(); |
| |
| /** return false to stop collecting */ |
| public abstract boolean collect(BytesRef bytes) throws IOException; |
| |
| /** the next segment's {@link TermsEnum} that is used to collect terms */ |
| public abstract void setNextEnum(TermsEnum termsEnum) throws IOException; |
| } |
| } |