X-Git-Url: https://git.mdrn.pl/pylucene.git/blobdiff_plain/a2e61f0c04805cfcb8706176758d1283c7e3a55c..aaeed5504b982cf3545252ab528713250aa33eed:/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 new file mode 100644 index 0000000..04d8b58 --- /dev/null +++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/de/GermanLightStemmer.java @@ -0,0 +1,138 @@ +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. + *

+ * This stemmer implements the "UniNE" algorithm in: + * Light Stemming Approaches for the French, Portuguese, German and Hungarian Languages + * 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; + } +}