pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/de/GermanLightStemmer.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/de/GermanLightStemmer.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/de/GermanLightStemmer.java
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+package org.apache.lucene.analysis.de;
+
+/**
+ * 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.
+ */
+
+/**
+ * Light Stemmer for German.
+ * <p>
+ * This stemmer implements the "UniNE" algorithm in:
+ * <i>Light Stemming Approaches for the French, Portuguese, German and Hungarian Languages</i>
+ * Jacques Savoy
+ */
+public class GermanLightStemmer {
+  
+  public int stem(char s[], int len) {   
+    for (int i = 0; i < len; i++)
+      switch(s[i]) {
+        case 'ä':
+        case 'à':
+        case 'á':
+        case 'â': s[i] = 'a'; break;
+        case 'ö':
+        case 'ò':
+        case 'ó':
+        case 'ô': s[i] = 'o'; break;
+        case 'ï':
+        case 'ì':
+        case 'í':
+        case 'î': s[i] = 'i'; break;
+        case 'ü': 
+        case 'ù': 
+        case 'ú':
+        case 'û': s[i] = 'u'; break;
+      }
+    
+    len = step1(s, len);
+    return step2(s, len);
+  }
+  
+  private boolean stEnding(char ch) {
+    switch(ch) {
+      case 'b':
+      case 'd':
+      case 'f':
+      case 'g':
+      case 'h':
+      case 'k':
+      case 'l':
+      case 'm':
+      case 'n':
+      case 't': return true;
+      default: return false;
+    }
+  }
+  
+  private int step1(char s[], int len) {
+    if (len > 5 && s[len-3] == 'e' && s[len-2] == 'r' && s[len-1] == 'n')
+      return len - 3;
+    
+    if (len > 4 && s[len-2] == 'e')
+      switch(s[len-1]) {
+        case 'm':
+        case 'n':
+        case 'r':
+        case 's': return len - 2;
+      }
+    
+    if (len > 3 && s[len-1] == 'e')
+      return len - 1;
+    
+    if (len > 3 && s[len-1] == 's' && stEnding(s[len-2]))
+      return len - 1;
+    
+    return len;
+  }
+  
+  private int step2(char s[], int len) {
+    if (len > 5 && s[len-3] == 'e' && s[len-2] == 's' && s[len-1] == 't')
+      return len - 3;
+    
+    if (len > 4 && s[len-2] == 'e' && (s[len-1] == 'r' || s[len-1] == 'n'))
+      return len - 2;
+    
+    if (len > 4 && s[len-2] == 's' && s[len-1] == 't' && stEnding(s[len-3]))
+      return len - 2;
+    
+    return len;
+  }
+}