| #if FEATURE_COLLATION |
| using Icu.Collation; |
| using Lucene.Net.Analysis; |
| using Lucene.Net.Analysis.Core; |
| using Lucene.Net.Util; |
| using System; |
| using System.IO; |
| |
| 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> |
| /// Configures <see cref="KeywordTokenizer"/> with <see cref="CollationAttributeFactory"/>. |
| /// </para> |
| /// <para> |
| /// Converts the token into its <see cref="System.Globalization.SortKey"/>, and then |
| /// encodes the <see cref="System.Globalization.SortKey"/> either directly or with |
| /// <see cref="IndexableBinaryStringTools"/> (see version note below), 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>ICUCollationKeyAnalyzer</c> in the analysis-icu package |
| /// uses ICU4J's Collator, which makes its |
| /// its version available, thus allowing collation to be versioned |
| /// independently from the JVM. ICUCollationKeyAnalyzer is also significantly |
| /// faster and generates significantly shorter keys than CollationKeyAnalyzer. |
| /// 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 |
| /// <see cref="Collator"/> over several languages. |
| /// </para> |
| /// <para> |
| /// CollationKeys generated by <see cref="Collator"/> are not compatible |
| /// with those those generated by ICU Collators. Specifically, if you use |
| /// CollationKeyAnalyzer to generate index terms, do not use |
| /// ICUCollationKeyAnalyzer on the query side, or vice versa. |
| /// </para> |
| /// <para>You must specify the required <see cref="LuceneVersion"/> |
| /// compatibility when creating <see cref="CollationKeyAnalyzer"/>: |
| /// <list type="bullet"> |
| /// <item><description> As of 4.0, Collation Keys are directly encoded as bytes. Previous |
| /// versions will encode the bytes with <see cref="IndexableBinaryStringTools"/>.</description></item> |
| /// </list> |
| /// </para> |
| /// </summary> |
| public sealed class CollationKeyAnalyzer : Analyzer |
| { |
| private readonly Collator collator; |
| private readonly CollationAttributeFactory factory; |
| private readonly LuceneVersion matchVersion; |
| |
| /// <summary> |
| /// Create a new <see cref="CollationKeyAnalyzer"/>, using the specified collator. |
| /// </summary> |
| /// <param name="matchVersion"> See <see cref="CollationKeyAnalyzer"/> </param> |
| /// <param name="collator"> <see cref="System.Globalization.SortKey"/> generator </param> |
| public CollationKeyAnalyzer(LuceneVersion matchVersion, Collator collator) |
| { |
| this.matchVersion = matchVersion; |
| this.collator = collator; |
| this.factory = new CollationAttributeFactory(collator); |
| } |
| |
| [Obsolete("Use <seealso cref=\"CollationKeyAnalyzer#CollationKeyAnalyzer(LuceneVersion, Collator)\"/> and specify a version instead. This ctor will be removed in Lucene 5.0")] |
| public CollationKeyAnalyzer(Collator collator) |
| : this(LuceneVersion.LUCENE_31, collator) |
| { |
| } |
| |
| protected override TokenStreamComponents CreateComponents(string fieldName, TextReader reader) |
| { |
| #pragma warning disable 612, 618 |
| if (this.matchVersion.OnOrAfter(LuceneVersion.LUCENE_40)) |
| #pragma warning restore 612, 618 |
| { |
| var tokenizer = new KeywordTokenizer(this.factory, reader, KeywordTokenizer.DEFAULT_BUFFER_SIZE); |
| return new TokenStreamComponents(tokenizer, tokenizer); |
| } |
| else |
| { |
| var tokenizer = new KeywordTokenizer(reader); |
| return new TokenStreamComponents(tokenizer, |
| #pragma warning disable 612, 618 |
| new CollationKeyFilter(tokenizer, this.collator)); |
| #pragma warning restore 612, 618 |
| } |
| } |
| } |
| } |
| #endif |