Lucene.Net/QueryParser/MultiFieldQueryParser.cs

   1 using System;
   2 using Lucene.Net.Analysis;
   3 using Lucene.Net.Search;
   4
   5 namespace Lucene.Net.QueryParsers
   6 {
   7         /* ====================================================================
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  60
  61         /// <summary>
  62         /// A QueryParser which constructs queries to search multiple fields.
  63         /// </summary>
  64         /// <author><a href="mailto:kelvin@relevanz.com">Kelvin Tan</a></author>
  65         /// <version>$Revision: 1.1.1.1 $</version>
  66         public class MultiFieldQueryParser : QueryParser
  67         {
  68                 public const int NORMAL_FIELD     = 0;
  69                 public const int REQUIRED_FIELD   = 1;
  70                 public const int PROHIBITED_FIELD = 2;
  71
  72                 public MultiFieldQueryParser(QueryParserTokenManager tm) : base(tm)
  73                 {
  74                 }
  75
  76                 public MultiFieldQueryParser(CharStream stream) : base(stream)
  77                 {
  78                 }
  79
  80                 public MultiFieldQueryParser(String f, Analyzer a) : base(f, a)
  81                 {
  82                 }
  83
  84                 /// <summary>
  85                 /// <p>Parses a query which searches on the fields specified.</p>
  86                 /// <p>If x fields are specified, this effectively constructs:</p>
  87                 /// <pre>
  88                 /// <code>
  89                 /// (field1:query) (field2:query) (field3:query)...(fieldx:query)
  90                 /// </code>
  91                 /// </pre>
  92                 /// </summary>
  93                 /// <param name="query">Query string to parse</param>
  94                 /// <param name="fields">Fields to search on</param>
  95                 /// <param name="analyzer">Analyzer to use</param>
  96                 /// <returns></returns>
  97                 /// <throws>ParserException if query parsing fails</throws>
  98                 /// <throws>TokenMgrError if query parsing fails</throws>
  99                 public static Query Parse(String query, String[] fields, Analyzer analyzer)
 100                 {
 101                         BooleanQuery bQuery = new BooleanQuery();
 102                         for (int i = 0; i < fields.Length; i++)
 103                         {
 104                                 Query q = Parse(query, fields[i], analyzer);
 105                                 bQuery.Add(q, false, false);
 106                         }
 107                         return bQuery;
 108                 }
 109
 110                 /// <summary>
 111                 /// <p>
 112                 /// Parses a query, searching on the fields specified.
 113                 /// Use this if you need to specify certain fields as required,
 114                 /// and others as prohibited.</p>
 115                 /// <p><pre>
 116                 /// Usage:
 117                 /// <code>
 118                 /// String[] fields = {"filename", "contents", "description"};
 119                 /// int[] flags = {MultiFieldQueryParser.NORMAL FIELD,
 120                 ///                MultiFieldQueryParser.REQUIRED FIELD,
 121                 ///                MultiFieldQueryParser.PROHIBITED FIELD,};
 122                 /// Parse(query, fields, flags, analyzer);
 123                 /// </code>
 124                 /// </pre></p>
 125                 ///<p>
 126                 /// The code above would construct a query:
 127                 /// <pre>
 128                 /// <code>
 129                 /// (filename:query) +(contents:query) -(description:query)
 130                 /// </code>
 131                 /// </pre></p>
 132                 /// </summary>
 133                 /// <param name="query">Query string to parse</param>
 134                 /// <param name="fields">Fields to search on</param>
 135                 /// <param name="flags">Flags describing the fields</param>
 136                 /// <param name="analyzer">Analyzer to use</param>
 137                 /// <returns></returns>
 138                 /// <throws>ParserException if query parsing fails</throws>
 139                 /// <throws>TokenMgrError if query parsing fails</throws>
 140                 public static Query Parse(String query, String[] fields, int[] flags,
 141                         Analyzer analyzer)
 142                 {
 143                         BooleanQuery bQuery = new BooleanQuery();
 144                         for (int i = 0; i < fields.Length; i++)
 145                         {
 146                                 Query q = Parse(query, fields[i], analyzer);
 147                                 int flag = flags[i];
 148                                 switch (flag)
 149                                 {
 150                                         case REQUIRED_FIELD:
 151                                                 bQuery.Add(q, true, false);
 152                                                 break;
 153                                         case PROHIBITED_FIELD:
 154                                                 bQuery.Add(q, false, true);
 155                                                 break;
 156                                         default:
 157                                                 bQuery.Add(q, false, false);
 158                                                 break;
 159                                 }
 160                         }
 161                         return bQuery;
 162                 }
 163         }
 164 }