pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/ru/RussianLightStemmer.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/ru/RussianLightStemmer.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/ru/RussianLightStemmer.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.
+ */
+
+/* 
+ * This algorithm is updated based on code located at:
+ * http://members.unine.ch/jacques.savoy/clef/
+ * 
+ * Full copyright for that code follows:
+ */
+
+/*
+ * Copyright (c) 2005, Jacques Savoy
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this 
+ * list of conditions and the following disclaimer. Redistributions in binary 
+ * form must reproduce the above copyright notice, this list of conditions and
+ * the following disclaimer in the documentation and/or other materials 
+ * provided with the distribution. Neither the name of the author nor the names 
+ * of its contributors may be used to endorse or promote products derived from 
+ * this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import static org.apache.lucene.analysis.util.StemmerUtil.*;
+
+/**
+ * Light Stemmer for Russian.
+ * <p>
+ * This stemmer implements the following algorithm:
+ * <i>Indexing and Searching Strategies for the Russian Language.</i>
+ * Ljiljana Dolamic and Jacques Savoy.
+ */
+public class RussianLightStemmer {
+
+  public int stem(char s[], int len) {
+    len = removeCase(s, len);
+    return normalize(s, len);
+  }
+  
+  private int normalize(char s[], int len) {
+    if (len > 3)
+      switch(s[len-1]) { 
+        case 'ь':
+        case 'и': return len - 1;
+        case 'н': if (s[len-2] == 'н') return len - 1;
+      }
+    return len;
+  }
+
+  private int removeCase(char s[], int len) {
+    if (len > 6 && 
+        (endsWith(s, len, "иями") ||
+         endsWith(s, len, "оями")))
+      return len - 4;
+    
+    if (len > 5 && 
+        (endsWith(s, len, "иям") ||
+         endsWith(s, len, "иях") ||
+         endsWith(s, len, "оях") ||
+         endsWith(s, len, "ями") ||
+         endsWith(s, len, "оям") ||
+         endsWith(s, len, "оьв") ||
+         endsWith(s, len, "ами") ||
+         endsWith(s, len, "его") ||
+         endsWith(s, len, "ему") ||
+         endsWith(s, len, "ери") ||
+         endsWith(s, len, "ими") ||
+         endsWith(s, len, "ого") ||
+         endsWith(s, len, "ому") ||
+         endsWith(s, len, "ыми") ||
+         endsWith(s, len, "оев")))
+      return len - 3;
+    
+    if (len > 4 &&
+        (endsWith(s, len, "ая") ||
+         endsWith(s, len, "яя") ||
+         endsWith(s, len, "ях") ||
+         endsWith(s, len, "юю") ||
+         endsWith(s, len, "ах") ||
+         endsWith(s, len, "ею") ||
+         endsWith(s, len, "их") ||
+         endsWith(s, len, "ия") ||
+         endsWith(s, len, "ию") ||
+         endsWith(s, len, "ьв") ||
+         endsWith(s, len, "ою") ||
+         endsWith(s, len, "ую") ||
+         endsWith(s, len, "ям") ||
+         endsWith(s, len, "ых") ||
+         endsWith(s, len, "ея") ||
+         endsWith(s, len, "ам") ||
+         endsWith(s, len, "ем") ||
+         endsWith(s, len, "ей") ||
+         endsWith(s, len, "ём") ||
+         endsWith(s, len, "ев") ||
+         endsWith(s, len, "ий") ||
+         endsWith(s, len, "им") ||
+         endsWith(s, len, "ое") ||
+         endsWith(s, len, "ой") ||
+         endsWith(s, len, "ом") ||
+         endsWith(s, len, "ов") ||
+         endsWith(s, len, "ые") ||
+         endsWith(s, len, "ый") ||
+         endsWith(s, len, "ым") ||
+         endsWith(s, len, "ми")))
+      return len - 2;
+    
+    if (len > 3)
+      switch(s[len-1]) {
+        case 'а':
+        case 'е':
+        case 'и':
+        case 'о':
+        case 'у':
+        case 'й':
+        case 'ы':
+        case 'я':
+        case 'ь': return len - 1;
+      }
+    
+    return len;
+  }
+}