org.elasticsearch.common.lucene.search.SpanBooleanQueryRewriteWithMaxClause Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.lucene.search;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexReaderContext;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.queries.SpanMatchNoDocsQuery;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.MultiTermQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.spans.SpanMultiTermQueryWrapper;
import org.apache.lucene.search.spans.SpanOrQuery;
import org.apache.lucene.search.spans.SpanQuery;
import org.apache.lucene.search.spans.SpanTermQuery;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.BytesRef;
import java.io.IOException;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
/**
* A span rewrite method that extracts the first maxExpansions
terms
* that match the {@link MultiTermQuery} in the terms dictionary.
* The rewrite throws an error if more than maxExpansions
terms are found and hardLimit
* is set.
*/
public class SpanBooleanQueryRewriteWithMaxClause extends SpanMultiTermQueryWrapper.SpanRewriteMethod {
private final int maxExpansions;
private final boolean hardLimit;
public SpanBooleanQueryRewriteWithMaxClause() {
this(BooleanQuery.getMaxClauseCount(), true);
}
public SpanBooleanQueryRewriteWithMaxClause(int maxExpansions, boolean hardLimit) {
this.maxExpansions = maxExpansions;
this.hardLimit = hardLimit;
}
public int getMaxExpansions() {
return maxExpansions;
}
public boolean isHardLimit() {
return hardLimit;
}
@Override
public SpanQuery rewrite(IndexReader reader, MultiTermQuery query) throws IOException {
final MultiTermQuery.RewriteMethod delegate = new MultiTermQuery.RewriteMethod() {
@Override
public Query rewrite(IndexReader reader, MultiTermQuery query) throws IOException {
Collection queries = collectTerms(reader, query);
if (queries.size() == 0) {
return new SpanMatchNoDocsQuery(query.getField(), "no expansion found for " + query.toString());
} else if (queries.size() == 1) {
return queries.iterator().next();
} else {
return new SpanOrQuery(queries.toArray(new SpanQuery[0]));
}
}
private Collection collectTerms(IndexReader reader, MultiTermQuery query) throws IOException {
Set queries = new HashSet<>();
IndexReaderContext topReaderContext = reader.getContext();
for (LeafReaderContext context : topReaderContext.leaves()) {
final Terms terms = context.reader().terms(query.getField());
if (terms == null) {
// field does not exist
continue;
}
final TermsEnum termsEnum = getTermsEnum(query, terms, new AttributeSource());
assert termsEnum != null;
if (termsEnum == TermsEnum.EMPTY) {
continue;
}
BytesRef bytes;
while ((bytes = termsEnum.next()) != null) {
if (queries.size() >= maxExpansions) {
if (hardLimit) {
throw new RuntimeException("[" + query.toString() + " ] " +
"exceeds maxClauseCount [ Boolean maxClauseCount is set to " + BooleanQuery.getMaxClauseCount() + "]");
} else {
return queries;
}
}
queries.add(new SpanTermQuery(new Term(query.getField(), bytes)));
}
}
return queries;
}
};
return (SpanQuery) delegate.rewrite(reader, query);
}
}