org.apache.lucene.search.spans.SpanQuery Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of hivemall-all
The newest version!
/*
 * 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.spans;


import java.io.IOException;
import java.util.Collection;
import java.util.Map;
import java.util.TreeMap;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermContext;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;

/** Base class for span-based queries. */
public abstract class SpanQuery extends Query {

  /**
   * Returns the name of the field matched by this query.
   */
  public abstract String getField();

  /**
   * Create a SpanWeight for this query
   * @param searcher the IndexSearcher to be searched across
   * @param needsScores if the query needs scores
   * @return a SpanWeight
   * @throws IOException on error
   */
  public abstract SpanWeight createWeight(IndexSearcher searcher, boolean needsScores) throws IOException;

  /**
   * Build a map of terms to termcontexts, for use in constructing SpanWeights
   * @lucene.internal
   */
  public static Map getTermContexts(SpanWeight... weights) {
    Map terms = new TreeMap<>();
    for (SpanWeight w : weights) {
      w.extractTermContexts(terms);
    }
    return terms;
  }

  /**
   * Build a map of terms to termcontexts, for use in constructing SpanWeights
   * @lucene.internal
   */
  public static Map getTermContexts(Collection weights) {
    Map terms = new TreeMap<>();
    for (SpanWeight w : weights) {
      w.extractTermContexts(terms);
    }
    return terms;
  }

  @Override
  public Query rewrite(IndexReader reader) throws IOException {
    if (super.getBoost() != 1f) {
      SpanQuery rewritten = (SpanQuery) clone();
      rewritten.setBoost(1f);
      return new SpanBoostQuery(rewritten, super.getBoost());
    }
    return this;
  }
}