beagled/Lucene.Net/Search/Spans/Spans.cs

   1 /*
   2  * Copyright 2004 The Apache Software Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 using System;
  18
  19 namespace Lucene.Net.Search.Spans
  20 {
  21
  22         /// <summary>Expert: an enumeration of span matches.  Used to implement span searching.
  23         /// Each span represents a range of term positions within a document.  Matches
  24         /// are enumerated in order, by increasing document number, within that by
  25         /// increasing start position and finally by increasing end position.
  26         /// </summary>
  27         public interface Spans
  28         {
  29                 /// <summary>Move to the next match, returning true iff any such exists. </summary>
  30                 bool Next();
  31
  32                 /// <summary>Skips to the first match beyond the current, whose document number is
  33                 /// greater than or equal to <i>target</i>. <p>Returns true iff there is such
  34                 /// a match.  <p>Behaves as if written: <pre>
  35                 /// boolean skipTo(int target) {
  36                 /// do {
  37                 /// if (!next())
  38                 /// return false;
  39                 /// } while (target > doc());
  40                 /// return true;
  41                 /// }
  42                 /// </pre>
  43                 /// Most implementations are considerably more efficient than that.
  44                 /// </summary>
  45                 bool SkipTo(int target);
  46
  47                 /// <summary>Returns the document number of the current match.  Initially invalid. </summary>
  48                 int Doc();
  49
  50                 /// <summary>Returns the start position of the current match.  Initially invalid. </summary>
  51                 int Start();
  52
  53                 /// <summary>Returns the end position of the current match.  Initially invalid. </summary>
  54                 int End();
  55         }
  56 }