| using Lucene.Net.Analysis; |
| using Lucene.Net.Analysis.TokenAttributes; |
| |
| namespace Lucene.Net.Search.Highlight |
| { |
| /* |
| * 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. |
| */ |
| |
| /// <summary> |
| /// This <see cref="TokenFilter"/> limits the number of tokens while indexing by adding up the |
| /// current offset. |
| /// </summary> |
| public sealed class OffsetLimitTokenFilter : TokenFilter |
| { |
| private int offsetCount; |
| private readonly IOffsetAttribute offsetAttrib; |
| private readonly int offsetLimit; |
| |
| public OffsetLimitTokenFilter(TokenStream input, int offsetLimit) : base(input) |
| { |
| this.offsetLimit = offsetLimit; |
| offsetAttrib = GetAttribute<IOffsetAttribute>(); |
| } |
| |
| public override bool IncrementToken() |
| { |
| if (offsetCount < offsetLimit && m_input.IncrementToken()) |
| { |
| int offsetLength = offsetAttrib.EndOffset - offsetAttrib.StartOffset; |
| offsetCount += offsetLength; |
| return true; |
| } |
| return false; |
| } |
| |
| public override void Reset() |
| { |
| base.Reset(); |
| offsetCount = 0; |
| } |
| } |
| } |