| #if FEATURE_COLLATION |
| using Icu.Collation; |
| using Lucene.Net.Analysis; |
| using Lucene.Net.Analysis.TokenAttributes; |
| using Lucene.Net.Util; |
| using System; |
| |
| namespace Lucene.Net.Collation |
| { |
| /* |
| * 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> |
| /// <para> |
| /// Converts each token into its <see cref="System.Globalization.SortKey"/>, and then |
| /// encodes the <see cref="System.Globalization.SortKey"/> with <see cref="IndexableBinaryStringTools"/>, to allow |
| /// it to be stored as an index term. |
| /// </para> |
| /// <para> |
| /// <strong>WARNING:</strong> Make sure you use exactly the same <see cref="Collator"/> at |
| /// index and query time -- <see cref="System.Globalization.SortKey"/> are only comparable when produced by |
| /// the same <see cref="Collator"/>. Since <c>java.text.RuleBasedCollators</c> are not |
| /// independently versioned, it is unsafe to search against stored |
| /// <see cref="System.Globalization.SortKey"/> unless the following are exactly the same (best practice is |
| /// to store this information with the index and check that they remain the |
| /// same at query time): |
| /// </para> |
| /// <list type="number"> |
| /// <item><description>JVM vendor</description></item> |
| /// <item><description>JVM version, including patch version</description></item> |
| /// <item><description> |
| /// The language (and country and variant, if specified) of the Locale |
| /// used when constructing the collator via |
| /// <see cref="Collator.Create(System.Globalization.CultureInfo)"/>. |
| /// </description></item> |
| /// <item><description> |
| /// The collation strength used - see <see cref="Collator.Strength"/> |
| /// </description></item> |
| /// </list> |
| /// <para> |
| /// The <c>ICUCollationKeyFilter</c> in the analysis-icu package |
| /// uses ICU4J's Collator, which makes its |
| /// version available, thus allowing collation to be versioned independently |
| /// from the JVM. ICUCollationKeyFilter is also significantly faster and |
| /// generates significantly shorter keys than CollationKeyFilter. See |
| /// <a href="http://site.icu-project.org/charts/collation-icu4j-sun" |
| /// >http://site.icu-project.org/charts/collation-icu4j-sun</a> for key |
| /// generation timing and key length comparisons between ICU4J and |
| /// java.text.Collator over several languages. |
| /// </para> |
| /// <para> |
| /// CollationKeys generated by java.text.Collators are not compatible |
| /// with those those generated by ICU Collators. Specifically, if you use |
| /// CollationKeyFilter to generate index terms, do not use |
| /// ICUCollationKeyFilter on the query side, or vice versa. |
| /// </para> </summary> |
| /// @deprecated Use <see cref="CollationAttributeFactory"/> instead, which encodes |
| /// terms directly as bytes. This filter will be removed in Lucene 5.0 |
| [Obsolete("Use CollationAttributeFactory instead, which encodes terms directly as bytes. This filter will be removed in Lucene 5.0.")] |
| public sealed class CollationKeyFilter : TokenFilter |
| { |
| private readonly Collator collator; |
| private readonly ICharTermAttribute termAtt; |
| |
| /// <param name="input"> Source token stream </param> |
| /// <param name="collator"> CollationKey generator </param> |
| public CollationKeyFilter(TokenStream input, Collator collator) |
| : base(input) |
| { |
| this.collator = collator; |
| this.termAtt = this.AddAttribute<ICharTermAttribute>(); |
| } |
| |
| public override bool IncrementToken() |
| { |
| if (this.m_input.IncrementToken()) |
| { |
| var collationKey = this.collator.GetSortKey(this.termAtt.ToString()).KeyData.ToSByteArray(); |
| var encodedLength = IndexableBinaryStringTools.GetEncodedLength(collationKey, 0, collationKey.Length); |
| this.termAtt.ResizeBuffer(encodedLength); |
| this.termAtt.Length = encodedLength; |
| |
| IndexableBinaryStringTools.Encode(collationKey, 0, collationKey.Length, this.termAtt.Buffer, 0, encodedLength); |
| return true; |
| } |
| else |
| { |
| return false; |
| } |
| } |
| } |
| |
| internal static class ByteArrayExtentions |
| { |
| internal static byte[] ToByteArray(this sbyte[] arr) |
| { |
| var unsigned = new byte[arr.Length]; |
| System.Buffer.BlockCopy(arr, 0, unsigned, 0, arr.Length); |
| return unsigned; |
| } |
| |
| internal static sbyte[] ToSByteArray(this byte[] arr) |
| { |
| var unsigned = new sbyte[arr.Length]; |
| System.Buffer.BlockCopy(arr, 0, unsigned, 0, arr.Length); |
| return unsigned; |
| } |
| } |
| } |
| #endif |