50 lines
1.8 KiB
C#
50 lines
1.8 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using Lucene.Net.QueryParsers;
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using Lucene.Net.Search;
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using Portoa.Persistence;
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using VideoGameQuotes.Api.Persistence;
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using Directory = Lucene.Net.Store.Directory;
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namespace VideoGameQuotes.Api.Search.Lucene {
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/// <summary>
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/// <see cref="ISearcher{T}"/> implementation for entities based on <c>Lucene.NET</c>
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/// </summary>
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public class LuceneEntitySearcher<T> : ISearcher<T> where T : Entity<T, int> {
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private readonly QueryParser queryParser;
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private readonly Directory indexDirectory;
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private readonly ISearchService<T> searchService;
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public LuceneEntitySearcher(QueryParser queryParser, Directory indexDirectory, ISearchService<T> searchService) {
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this.queryParser = queryParser;
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this.indexDirectory = indexDirectory;
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this.searchService = searchService;
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}
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public IEnumerable<SearchResult<T>> Search(string searchString, int maxResults = 10) {
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if (string.IsNullOrWhiteSpace(searchString)) {
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return Enumerable.Empty<SearchResult<T>>();
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}
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if (maxResults < 0) {
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throw new ArgumentOutOfRangeException("maxResults", maxResults, "Maximum number of results must be greater than or equal to zero");
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}
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if (maxResults == 0) {
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maxResults = int.MaxValue;
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}
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var query = queryParser.Parse(QueryParser.Escape(searchString));
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var searcher = new IndexSearcher(indexDirectory, true);
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try {
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var docs = searcher
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.Search(query, maxResults)
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.scoreDocs;
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var quotes = searchService.FindByIds(docs.Select(doc => int.Parse(searcher.Doc(doc.doc).GetField("id").StringValue())));
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return quotes.Zip(docs, (entity, doc) => new SearchResult<T> { Entity = entity, Score = doc.score }).ToArray();
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} finally {
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searcher.Close();
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}
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}
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}
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}
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