| using Lucene.Net.Analysis.TokenAttributes; |
| |
| namespace Lucene.Net.Analysis.Payloads |
| { |
| /* |
| * 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> |
| /// Characters before the delimiter are the "token", those after are the payload. |
| /// <para/> |
| /// For example, if the delimiter is '|', then for the string "foo|bar", foo is the token |
| /// and "bar" is a payload. |
| /// <para/> |
| /// Note, you can also include a <see cref="IPayloadEncoder"/> to convert the payload in an appropriate way (from characters to bytes). |
| /// <para/> |
| /// Note make sure your <see cref="Tokenizer"/> doesn't split on the delimiter, or this won't work |
| /// </summary> |
| /// <seealso cref="IPayloadEncoder"/> |
| public sealed class DelimitedPayloadTokenFilter : TokenFilter |
| { |
| public const char DEFAULT_DELIMITER = '|'; |
| private readonly char delimiter; |
| private readonly ICharTermAttribute termAtt; |
| private readonly IPayloadAttribute payAtt; |
| private readonly IPayloadEncoder encoder; |
| |
| |
| public DelimitedPayloadTokenFilter(TokenStream input, char delimiter, IPayloadEncoder encoder) |
| : base(input) |
| { |
| this.delimiter = delimiter; |
| this.encoder = encoder; |
| termAtt = AddAttribute<ICharTermAttribute>(); |
| payAtt = AddAttribute<IPayloadAttribute>(); |
| } |
| |
| public override bool IncrementToken() |
| { |
| if (m_input.IncrementToken()) |
| { |
| char[] buffer = termAtt.Buffer; |
| int length = termAtt.Length; |
| for (int i = 0; i < length; i++) |
| { |
| if (buffer[i] == delimiter) |
| { |
| payAtt.Payload = encoder.Encode(buffer, i + 1, (length - (i + 1))); |
| termAtt.Length = i; // simply set a new length |
| return true; |
| } |
| } |
| // we have not seen the delimiter |
| payAtt.Payload = null; |
| return true; |
| } |
| else |
| { |
| return false; |
| } |
| } |
| } |
| } |