SearchFiles.cs

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/* 
 * 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.
 */

using System;
using System.IO;
using System.Text;
using Lucene.Net.Analysis;
using Lucene.Net.Analysis.Standard;
using Lucene.Net.Documents;
using Lucene.Net.QueryParsers;
using Lucene.Net.Index;
using Lucene.Net.Search;
using FSDirectory = Lucene.Net.Store.FSDirectory;
using Version = Lucene.Net.Util.Version;

namespace Lucene.Net.Demo
{
    
    /// <summary>Simple command-line based search demo. </summary>
    public static class SearchFiles
    {
        private class AnonymousClassCollector : Collector
        {
            private Scorer scorer;
            private int docBase;
            
            // simply print docId and score of every matching document
            public override void Collect(int doc)
            {
                Console.Out.WriteLine("doc=" + doc + docBase + " score=" + scorer.Score());
            }
            
            public override bool AcceptsDocsOutOfOrder
            {
                get { return true; }
            }
            
            public override void SetNextReader(IndexReader reader, int docBase)
            {
                this.docBase = docBase;
            }
            
            public override void  SetScorer(Scorer scorer)
            {
                this.scorer = scorer;
            }
        }
        
        /// <summary>
        /// Use the norms from one field for all fields.  Norms are read into memory,
        /// using a byte of memory per document per searched field.  This can cause
        /// search of large collections with a large number of fields to run out of
        /// memory.  If all of the fields contain only a single token, then the norms
        /// are all identical, then single norm vector may be shared. 
        /// </summary>
        private class OneNormsReader : FilterIndexReader
        {
            private readonly String field;
            
            public OneNormsReader(IndexReader in_Renamed, String field):base(in_Renamed)
            {
                this.field = field;
            }
            
            public override byte[] Norms(String field)
            {
                return in_Renamed.Norms(this.field);
            }
        }
                
        /// <summary>Simple command-line based search demo. </summary>
        [STAThread]
        public static void Main(String[] args)
        {
            String usage = "Usage:\t" + typeof(SearchFiles) + "[-index dir] [-field f] [-repeat n] [-queries file] [-raw] [-norms field] [-paging hitsPerPage]";
            usage += "\n\tSpecify 'false' for hitsPerPage to use streaming instead of paging search.";
            if (args.Length > 0 && ("-h".Equals(args[0]) || "-help".Equals(args[0])))
            {
                Console.Out.WriteLine(usage);
                Environment.Exit(0);
            }
            
            String index = "index";
            String field = "contents";
            String queries = null;
            int repeat = 0;
            bool raw = false;
            String normsField = null;
            bool paging = true;
            int hitsPerPage = 10;
            
            for (int i = 0; i < args.Length; i++)
            {
                if ("-index".Equals(args[i]))
                {
                    index = args[i + 1];
                    i++;
                }
                else if ("-field".Equals(args[i]))
                {
                    field = args[i + 1];
                    i++;
                }
                else if ("-queries".Equals(args[i]))
                {
                    queries = args[i + 1];
                    i++;
                }
                else if ("-repeat".Equals(args[i]))
                {
                    repeat = Int32.Parse(args[i + 1]);
                    i++;
                }
                else if ("-raw".Equals(args[i]))
                {
                    raw = true;
                }
                else if ("-norms".Equals(args[i]))
                {
                    normsField = args[i + 1];
                    i++;
                }
                else if ("-paging".Equals(args[i]))
                {
                    if (args[i + 1].Equals("false"))
                    {
                        paging = false;
                    }
                    else
                    {
                        hitsPerPage = Int32.Parse(args[i + 1]);
                        if (hitsPerPage == 0)
                        {
                            paging = false;
                        }
                    }
                    i++;
                }
            }

            IndexReader indexReader = null;
            try
            {
                // only searching, so read-only=true
                indexReader = IndexReader.Open(FSDirectory.Open(new System.IO.DirectoryInfo(index)), true); // only searching, so read-only=true

                if (normsField != null)
                    indexReader = new OneNormsReader(indexReader, normsField);
            
                Searcher searcher = new IndexSearcher(indexReader);
                Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_30);
            
                StreamReader queryReader;
                if (queries != null)
                {
                    queryReader = new StreamReader(new StreamReader(queries, Encoding.Default).BaseStream, new StreamReader(queries, Encoding.Default).CurrentEncoding);
                }
                else
                {
                    queryReader = new StreamReader(new StreamReader(Console.OpenStandardInput(), Encoding.UTF8).BaseStream, new StreamReader(Console.OpenStandardInput(), Encoding.UTF8).CurrentEncoding);
                }

                var parser = new QueryParser(Version.LUCENE_30, field, analyzer);
                while (true)
                {
                    if (queries == null)
                    // prompt the user
                        Console.Out.WriteLine("Enter query: ");
                
                    String line = queryReader.ReadLine();
                
                    if (line == null || line.Length == - 1)
                        break;
                
                    line = line.Trim();
                    if (line.Length == 0)
                        break;
                
                    Query query = parser.Parse(line);
                    Console.Out.WriteLine("Searching for: " + query.ToString(field));
                
                    if (repeat > 0)
                    {
                        // repeat & time as benchmark
                        DateTime start = DateTime.Now;
                        for (int i = 0; i < repeat; i++)
                        {
                            searcher.Search(query, null, 100);
                        }
                        DateTime end = DateTime.Now;
                        Console.Out.WriteLine("Time: " + (end.Millisecond - start.Millisecond) + "ms");
                    }
                
                    if (paging)
                    {
                        DoPagingSearch(queryReader, searcher, query, hitsPerPage, raw, queries == null);
                    }
                    else
                    {
                        DoStreamingSearch(searcher, query);
                    }
                }
                queryReader.Close();
            } 
            finally 
            {
                if (indexReader != null)
                {
                    indexReader.Dispose();
                }
            }
        }
        
        /// <summary>
        /// This method uses a custom HitCollector implementation which simply prints out
        /// the docId and score of every matching document. 
        /// 
        /// This simulates the streaming search use case, where all hits are supposed to
        /// be processed, regardless of their relevance.
        /// </summary>
        public static void  DoStreamingSearch(Searcher searcher, Query query)
        {
            Collector streamingHitCollector = new AnonymousClassCollector();
            searcher.Search(query, streamingHitCollector);
        }
        
        /// <summary> This demonstrates a typical paging search scenario, where the search engine presents 
        /// pages of size n to the user. The user can then go to the next page if interested in
        /// the next hits.
        /// 
        /// When the query is executed for the first time, then only enough results are collected
        /// to fill 5 result pages. If the user wants to page beyond this limit, then the query
        /// is executed another time and all hits are collected.
        /// 
        /// </summary>
        public static void  DoPagingSearch(StreamReader input, Searcher searcher, Query query, int hitsPerPage, bool raw, bool interactive)
        {
            
            // Collect enough docs to show 5 pages
            var collector = TopScoreDocCollector.Create(5 * hitsPerPage, false);
            searcher.Search(query, collector);
            var hits = collector.TopDocs().ScoreDocs;
            
            int numTotalHits = collector.TotalHits;
            Console.Out.WriteLine(numTotalHits + " total matching documents");
            
            int start = 0;
            int end = Math.Min(numTotalHits, hitsPerPage);
            
            while (true)
            {
                if (end > hits.Length)
                {
                    Console.Out.WriteLine("Only results 1 - " + hits.Length + " of " + numTotalHits + " total matching documents collected.");
                    Console.Out.WriteLine("Collect more (y/n) ?");
                    String line = input.ReadLine();
                    if (String.IsNullOrEmpty(line) || line[0] == 'n')
                    {
                        break;
                    }
                    
                    collector = TopScoreDocCollector.Create(numTotalHits, false);
                    searcher.Search(query, collector);
                    hits = collector.TopDocs().ScoreDocs;
                }
                
                end = Math.Min(hits.Length, start + hitsPerPage);
                
                for (int i = start; i < end; i++)
                {
                    if (raw)
                    {
                        // output raw format
                        Console.Out.WriteLine("doc=" + hits[i].Doc + " score=" + hits[i].Score);
                        continue;
                    }
                    
                    Document doc = searcher.Doc(hits[i].Doc);
                    String path = doc.Get("path");
                    if (path != null)
                    {
                        Console.Out.WriteLine((i + 1) + ". " + path);
                        String title = doc.Get("title");
                        if (title != null)
                        {
                            Console.Out.WriteLine("   Title: " + doc.Get("title"));
                        }
                    }
                    else
                    {
                        Console.Out.WriteLine((i + 1) + ". " + "No path for this document");
                    }
                }
                
                if (!interactive)
                {
                    break;
                }
                
                if (numTotalHits >= end)
                {
                    bool quit = false;
                    while (true)
                    {
                        Console.Out.Write("Press ");
                        if (start - hitsPerPage >= 0)
                        {
                            Console.Out.Write("(p)revious page, ");
                        }
                        if (start + hitsPerPage < numTotalHits)
                        {
                            Console.Out.Write("(n)ext page, ");
                        }
                        Console.Out.WriteLine("(q)uit or enter number to jump to a page.");
                        
                        String line = input.ReadLine();
                        if (String.IsNullOrEmpty(line) || line[0] == 'q')
                        {
                            quit = true;
                            break;
                        }
                        if (line[0] == 'p')
                        {
                            start = Math.Max(0, start - hitsPerPage);
                            break;
                        }
                        else if (line[0] == 'n')
                        {
                            if (start + hitsPerPage < numTotalHits)
                            {
                                start += hitsPerPage;
                            }
                            break;
                        }
                        else
                        {
                            int page = Int32.Parse(line);
                            if ((page - 1) * hitsPerPage < numTotalHits)
                            {
                                start = (page - 1) * hitsPerPage;
                                break;
                            }
                            else
                            {
                                Console.Out.WriteLine("No such page");
                            }
                        }
                    }
                    if (quit)
                        break;
                    end = Math.Min(numTotalHits, start + hitsPerPage);
                }
            }
        }
    }
}