/*
* 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.uhighlight;
import java.io.IOException;
import org.apache.lucene.index.Fields;
import org.apache.lucene.index.FilterLeafReader;
import org.apache.lucene.index.LeafReader;
import org.apache.lucene.index.PostingsEnum;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.automaton.CompiledAutomaton;
/**
* A filtered LeafReader that only includes the terms that are also in a provided set of terms.
* Certain methods may be unimplemented or cause large operations on the underlying reader
* and be slow.
*
* @lucene.internal
*/
final class TermVectorFilteredLeafReader extends FilterLeafReader {
// NOTE: super ("in") is baseLeafReader
private final Terms filterTerms;
/**
* <p>Construct a FilterLeafReader based on the specified base reader.
* <p>Note that base reader is closed if this FilterLeafReader is closed.</p>
*
* @param baseLeafReader full/original reader.
* @param filterTerms set of terms to filter by -- probably from a TermVector or MemoryIndex.
*/
TermVectorFilteredLeafReader(LeafReader baseLeafReader, Terms filterTerms) {
super(baseLeafReader);
this.filterTerms = filterTerms;
}
@Override
public Fields fields() throws IOException {
return new TermVectorFilteredFields(in.fields(), filterTerms);
}
private static final class TermVectorFilteredFields extends FilterLeafReader.FilterFields {
// NOTE: super ("in") is baseFields
private final Terms filterTerms;
TermVectorFilteredFields(Fields baseFields, Terms filterTerms) {
super(baseFields);
this.filterTerms = filterTerms;
}
@Override
public Terms terms(String field) throws IOException {
return new TermsFilteredTerms(in.terms(field), filterTerms);
}
}
private static final class TermsFilteredTerms extends FilterLeafReader.FilterTerms {
// NOTE: super ("in") is the baseTerms
private final Terms filterTerms;
TermsFilteredTerms(Terms baseTerms, Terms filterTerms) {
super(baseTerms);
this.filterTerms = filterTerms;
}
//TODO delegate size() ?
//TODO delegate getMin, getMax to filterTerms
@Override
public TermsEnum iterator() throws IOException {
return new TermVectorFilteredTermsEnum(in.iterator(), filterTerms.iterator());
}
@Override
public TermsEnum intersect(CompiledAutomaton compiled, BytesRef startTerm) throws IOException {
return new TermVectorFilteredTermsEnum(in.iterator(), filterTerms.intersect(compiled, startTerm));
}
}
private static final class TermVectorFilteredTermsEnum extends FilterLeafReader.FilterTermsEnum {
// NOTE: super ("in") is the filteredTermsEnum. This is different than wrappers above because we
// navigate the terms using the filter.
//TODO: track the last term state from the term state method and do some potential optimizations
private final TermsEnum baseTermsEnum;
TermVectorFilteredTermsEnum(TermsEnum baseTermsEnum, TermsEnum filteredTermsEnum) {
super(filteredTermsEnum); // note this is reversed from constructors above
this.baseTermsEnum = baseTermsEnum;
}
//TODO delegate docFreq & ttf (moveToCurrentTerm() then call on full?
@Override
public PostingsEnum postings(PostingsEnum reuse, int flags) throws IOException {
moveToCurrentTerm();
return baseTermsEnum.postings(reuse, flags);
}
void moveToCurrentTerm() throws IOException {
BytesRef currentTerm = in.term(); // from filteredTermsEnum
boolean termInBothTermsEnum = baseTermsEnum.seekExact(currentTerm);
if (!termInBothTermsEnum) {
throw new IllegalStateException("Term vector term " + currentTerm + " does not appear in full index.");
}
}
}
@Override
public CacheHelper getCoreCacheHelper() {
return null;
}
@Override
public CacheHelper getReaderCacheHelper() {
return null;
}
}