1   package org.apache.lucene.search.spans;
    2   
    3   /**
    4    * Licensed to the Apache Software Foundation (ASF) under one or more
    5    * contributor license agreements.  See the NOTICE file distributed with
    6    * this work for additional information regarding copyright ownership.
    7    * The ASF licenses this file to You under the Apache License, Version 2.0
    8    * (the "License"); you may not use this file except in compliance with
    9    * the License.  You may obtain a copy of the License at
   10    *
   11    *     http://www.apache.org/licenses/LICENSE-2.0
   12    *
   13    * Unless required by applicable law or agreed to in writing, software
   14    * distributed under the License is distributed on an "AS IS" BASIS,
   15    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   16    * See the License for the specific language governing permissions and
   17    * limitations under the License.
   18    */
   19   
   20   import java.io.IOException;
   21   
   22   import org.apache.lucene.index.IndexReader;
   23   import org.apache.lucene.search.Query;
   24   import org.apache.lucene.search.Searcher;
   25   import org.apache.lucene.search.Weight;
   26   
   27   /** Base class for span-based queries. */
   28   public abstract class SpanQuery extends Query {
   29     /** Expert: Returns the matches for this query in an index.  Used internally
   30      * to search for spans. */
   31     public abstract Spans getSpans(IndexReader reader) throws IOException;
   32   
   33     /** Returns the name of the field matched by this query.*/
   34     public abstract String getField();
   35   
   36     @Override
   37     public Weight createWeight(Searcher searcher) throws IOException {
   38       return new SpanWeight(this, searcher);
   39     }
   40   
   41   }