ArabicStemFilter.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.Collections;

using Lucene.Net.Analysis;
using Lucene.Net.Analysis.Tokenattributes;
using Lucene.Net.Util;


namespace Lucene.Net.Analysis.AR
{


    /*
     * A <see cref="TokenFilter"/> that applies <see cref="ArabicStemmer"/> to stem Arabic words..
     * 
     */

    public class ArabicStemFilter : TokenFilter
    {

        private readonly ArabicStemmer stemmer;
        private readonly ITermAttribute termAtt;

        public ArabicStemFilter(TokenStream input) : base(input)
        {
            stemmer = new ArabicStemmer();
            termAtt = AddAttribute<ITermAttribute>();
        }

        public override bool IncrementToken()
        {
            if (input.IncrementToken())
            {
                int newlen = stemmer.Stem(termAtt.TermBuffer(), termAtt.TermLength());
                termAtt.SetTermLength(newlen);
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}