RegexTermEnum.cs :  » Search-Engines » dotLucene » Lucene » Net » Search » Regex » C# / CSharp Open Source

/*
 * Copyright 2004 The Apache Software Foundation
 * 
 * Licensed 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 IndexReaderLucene.Net.Index.IndexReader;
using TermLucene.Net.Index.Term;
using FilteredTermEnumLucene.Net.Search.FilteredTermEnum;
// using Pattern = java.util.regex.Pattern;     {{Aroush-1.9}}

namespace Lucene.Net.Search.Regex{
  
  public class RegexTermEnum : FilteredTermEnum
  {
    private System.String field = "";
    private System.String pre = "";
    internal bool endEnum = false;
    // private Pattern pattern;     {{Aroush-1.9}}
    
    public RegexTermEnum(IndexReader reader, Term term) : base()
    {
      field = term.Field();
      System.String text = term.Text();
      
      // pattern = Pattern.compile(text);     {{Aroush-1.9}} how do we do this in .NET 1.1?!
      
      // Find the first regex character position, to find the
      // maximum prefix to use for term enumeration
      int index = 0;
      while (index < text.Length)
      {
        char c = text[index];
        
        if (!System.Char.IsLetterOrDigit(c))
          break;
        
        index++;
      }
      
      pre = text.Substring(0, (index) - (0));
      
      SetEnum(reader.Terms(new Term(term.Field(), pre)));
    }
    
    protected internal override bool TermCompare(Term term)
    {
      if ((System.Object) field == (System.Object) term.Field())
      {
        System.String searchText = term.Text();
        if (searchText.StartsWith(pre))
        {
          // return pattern.matcher(searchText).matches();    {{Aroush-1.9}} how do we do this in .NET 1.1?!
                    return (false);
        }
      }
      endEnum = true;
      return false;
    }
    
    public override float Difference()
    {
      // TODO: adjust difference based on distance of searchTerm.text() and term().text()
      return 1.0f;
    }
    
    public override bool EndEnum()
    {
      return endEnum;
    }
    
    public override void  Close()
    {
      base.Close();
      field = null;
    }
  }
}