| // lucene version compatibility level: 4.8.1 |
| using ICU4N.Text; |
| using Lucene.Net.Analysis; |
| using Lucene.Net.Analysis.Core; |
| using Lucene.Net.Support; |
| 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> |
| /// Configures <see cref="KeywordTokenizer"/> with <see cref="ICUCollationAttributeFactory"/>. |
| /// </summary> |
| /// <remarks> |
| /// Converts the token into its <see cref="CollationKey"/>, and |
| /// then encodes the <see cref="CollationKey"/> either directly or with |
| /// <see cref="IndexableBinaryStringTools"/> (see <a href="#version">below</a>), to allow it to |
| /// be stored as an index term. |
| /// <para/> |
| /// <strong>WARNING:</strong> Make sure you use exactly the same <see cref="Collator"/> at |
| /// index and query time -- CollationKeys are only comparable when produced by |
| /// the same <see cref="Collator"/>. <see cref="RuleBasedCollator"/>s are |
| /// independently versioned, so it is safe to search against stored |
| /// <see cref="CollationKey"/>s if 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): |
| /// <list type="number"> |
| /// <item><description>Collator version - see <see cref="Collator"/> Version</description></item> |
| /// <item><description>The collation strength used - see <see cref="Collator.Strength"/></description></item> |
| /// </list> |
| /// <para/> |
| /// <see cref="CollationKey"/>s generated by ICU Collators are not compatible with those |
| /// generated by java.text.Collators. Specifically, if you use |
| /// <see cref="ICUCollationKeyAnalyzer"/> to generate index terms, do not use |
| /// CollationKeyAnalyzer on the query side, or vice versa. |
| /// <para/> |
| /// ICUCollationKeyAnalyzer is 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 |
| /// java.text.Collator over several languages. |
| /// <para/> |
| /// <a name="version"/> |
| /// You must specify the required <see cref="LuceneVersion"/> |
| /// compatibility when creating <see cref="ICUCollationKeyAnalyzer"/>: |
| /// <list type="bullet"> |
| /// <item><description>As of 4.0, <see cref="CollationKey"/>s are directly encoded as bytes. Previous |
| /// versions will encode the bytes with <see cref="IndexableBinaryStringTools"/>.</description></item> |
| /// </list> |
| /// </remarks> |
| [ExceptionToClassNameConvention] |
| public sealed class ICUCollationKeyAnalyzer : Analyzer |
| { |
| private readonly Collator collator; |
| private readonly ICUCollationAttributeFactory factory; |
| private readonly LuceneVersion matchVersion; |
| |
| /// <summary> |
| /// Create a new <see cref="ICUCollationKeyAnalyzer"/>, using the specified <paramref name="collator"/>. |
| /// </summary> |
| /// <param name="matchVersion">See <see cref="ICUCollationKeyAnalyzer"/>.</param> |
| /// <param name="collator"><see cref="CollationKey"/> generator.</param> |
| public ICUCollationKeyAnalyzer(LuceneVersion matchVersion, Collator collator) |
| { |
| this.matchVersion = matchVersion; |
| this.collator = collator; |
| this.factory = new ICUCollationAttributeFactory(collator); |
| } |
| |
| [Obsolete("Use ICUCollationKeyAnalyzer.ICUCollationKeyAnalyzer(LuceneVersion, Collator) and specify a version instead. This ctor will be removed in Lucene 5.0")] |
| public ICUCollationKeyAnalyzer(Collator collator) |
| : this(LuceneVersion.LUCENE_31, collator) |
| { |
| } |
| |
| protected internal override TokenStreamComponents CreateComponents(string fieldName, TextReader reader) |
| { |
| #pragma warning disable 612, 618 |
| if (matchVersion.OnOrAfter(LuceneVersion.LUCENE_40)) |
| #pragma warning restore 612, 618 |
| { |
| KeywordTokenizer tokenizer = new KeywordTokenizer(factory, reader, KeywordTokenizer.DEFAULT_BUFFER_SIZE); |
| return new TokenStreamComponents(tokenizer, tokenizer); |
| } |
| else |
| { |
| KeywordTokenizer tokenizer = new KeywordTokenizer(reader); |
| return new TokenStreamComponents(tokenizer, |
| #pragma warning disable 612, 618 |
| new ICUCollationKeyFilter(tokenizer, collator)); |
| #pragma warning restore 612, 618 |
| } |
| } |
| } |
| } |