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Java > Open Source Codes > org > apache > lucene > analysis > LengthFilter


1 package org.apache.lucene.analysis;
2
3 /**
4  * Copyright 2004 The Apache Software Foundation
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 import java.io.IOException JavaDoc;
20
21 /**
22  * Removes words that are too long and too short from the stream.
23  *
24  * @author David Spencer
25  * @version $Id: LengthFilter.java 347992 2005-11-21 21:41:43Z dnaber $
26  */
27 public final class LengthFilter extends TokenFilter {
28
29   final int min;
30   final int max;
31
32   /**
33    * Build a filter that removes words that are too long or too
34    * short from the text.
35    */
36   public LengthFilter(TokenStream in, int min, int max)
37   {
38     super(in);
39     this.min = min;
40     this.max = max;
41   }
42
43   /**
44    * Returns the next input Token whose termText() is the right len
45    */
46   public final Token next() throws IOException JavaDoc
47   {
48     // return the first non-stop word found
49 for (Token token = input.next(); token != null; token = input.next())
50     {
51       int len = token.termText().length();
52       if (len >= min && len <= max) {
53           return token;
54       }
55       // note: else we ignore it but should we index each part of it?
56 }
57     // reached EOS -- return null
58 return null;
59   }
60 }
61
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