/*
 * COPIED FROM APACHE LUCENE 4.7.2
 *
 * Git URL: git@github.com:apache/lucene.git, tag: releases/lucene-solr/4.7.2, path: lucene/core/src/java
 *
 * (see https://issues.apache.org/jira/browse/OAK-10786 for details)
 */

package org.apache.lucene.search.spans;

/*
 * 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.
 */

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

import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermContext;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Weight;
import org.apache.lucene.util.Bits;

/** Base class for span-based queries. */
public abstract class SpanQuery extends Query {
  /** Expert: Returns the matches for this query in an index.  Used internally
   * to search for spans. */
  public abstract Spans getSpans(AtomicReaderContext context, Bits acceptDocs, Map<Term,TermContext> termContexts) throws IOException;

  /** 
   * Returns the name of the field matched by this query.
   * <p>
   * Note that this may return null if the query matches no terms.
   */
  public abstract String getField();

  @Override
  public Weight createWeight(IndexSearcher searcher) throws IOException {
    return new SpanWeight(this, searcher);
  }

}
