pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / analyzers / common / src / java / org / apache / lucene / analysis / ru / RussianStemFilter.java

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/ru/RussianStemFilter.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/ru/RussianStemFilter.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/ru/RussianStemFilter.java
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+package org.apache.lucene.analysis.ru;
+
+/**
+ * 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.
+ */
+
+import org.apache.lucene.analysis.KeywordMarkerFilter;// for javadoc
+import org.apache.lucene.analysis.LowerCaseFilter; // for javadoc
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.tokenattributes.KeywordAttribute;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.analysis.ru.RussianStemmer;//javadoc @link
+import org.apache.lucene.analysis.snowball.SnowballFilter; // javadoc @link
+
+import java.io.IOException;
+
+/**
+ * A {@link TokenFilter} that stems Russian words. 
+ * <p>
+ * The implementation was inspired by GermanStemFilter.
+ * The input should be filtered by {@link LowerCaseFilter} before passing it to RussianStemFilter ,
+ * because RussianStemFilter only works with lowercase characters.
+ * </p>
+ * <p>
+ * To prevent terms from being stemmed use an instance of
+ * {@link KeywordMarkerFilter} or a custom {@link TokenFilter} that sets
+ * the {@link KeywordAttribute} before this {@link TokenStream}.
+ * </p>
+ * @see KeywordMarkerFilter
+ * @deprecated Use {@link SnowballFilter} with 
+ * {@link org.tartarus.snowball.ext.RussianStemmer} instead, which has the
+ * same functionality. This filter will be removed in Lucene 4.0
+ */
+@Deprecated
+public final class RussianStemFilter extends TokenFilter
+{
+    /**
+     * The actual token in the input stream.
+     */
+    private RussianStemmer stemmer = new RussianStemmer();
+
+    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+    private final KeywordAttribute keywordAttr = addAttribute(KeywordAttribute.class);
+
+    public RussianStemFilter(TokenStream in)
+    {
+        super(in);
+    }
+    /**
+     * Returns the next token in the stream, or null at EOS
+     */
+    @Override
+    public final boolean incrementToken() throws IOException
+    {
+      if (input.incrementToken()) {
+        if(!keywordAttr.isKeyword()) {
+          final String term = termAtt.toString();
+          final String s = stemmer.stem(term);
+          if (s != null && !s.equals(term))
+            termAtt.setEmpty().append(s);
+        }
+        return true;
+      } else {
+        return false;
+      }
+    }
+
+
+    /**
+     * Set a alternative/custom {@link RussianStemmer} for this filter.
+     */
+    public void setStemmer(RussianStemmer stemmer)
+    {
+        if (stemmer != null)
+        {
+            this.stemmer = stemmer;
+        }
+    }
+}