pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/gl/GalicianAnalyzer.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/gl/GalicianAnalyzer.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/gl/GalicianAnalyzer.java
@@ -0,0 +1,130 @@
+package org.apache.lucene.analysis.gl;
+
+/**
+ * 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 java.io.IOException;
+import java.io.Reader;
+import java.util.Set;
+
+import org.apache.lucene.analysis.Analyzer;
+import org.apache.lucene.analysis.LowerCaseFilter;
+import org.apache.lucene.analysis.StopFilter;
+import org.apache.lucene.analysis.KeywordMarkerFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.standard.StandardFilter;
+import org.apache.lucene.analysis.standard.StandardTokenizer;
+import org.apache.lucene.analysis.CharArraySet;
+import org.apache.lucene.analysis.StopwordAnalyzerBase;
+import org.apache.lucene.analysis.WordlistLoader;
+import org.apache.lucene.util.IOUtils;
+import org.apache.lucene.util.Version;
+
+/**
+ * {@link Analyzer} for Galician.
+ */
+public final class GalicianAnalyzer extends StopwordAnalyzerBase {
+  private final Set<?> stemExclusionSet;
+  
+  /** File containing default Galician stopwords. */
+  public final static String DEFAULT_STOPWORD_FILE = "stopwords.txt";
+  
+  /**
+   * Returns an unmodifiable instance of the default stop words set.
+   * @return default stop words set.
+   */
+  public static Set<?> getDefaultStopSet(){
+    return DefaultSetHolder.DEFAULT_STOP_SET;
+  }
+  
+  /**
+   * Atomically loads the DEFAULT_STOP_SET in a lazy fashion once the outer class 
+   * accesses the static final set the first time.;
+   */
+  private static class DefaultSetHolder {
+    static final Set<?> DEFAULT_STOP_SET;
+
+    static {
+      try {
+        DEFAULT_STOP_SET = WordlistLoader.getWordSet(IOUtils.getDecodingReader(GalicianAnalyzer.class, 
+            DEFAULT_STOPWORD_FILE, IOUtils.CHARSET_UTF_8), Version.LUCENE_CURRENT);
+      } catch (IOException ex) {
+        // default set should always be present as it is part of the
+        // distribution (JAR)
+        throw new RuntimeException("Unable to load default stopword set", ex);
+      }
+    }
+  }
+
+  /**
+   * Builds an analyzer with the default stop words: {@link #DEFAULT_STOPWORD_FILE}.
+   */
+  public GalicianAnalyzer(Version matchVersion) {
+    this(matchVersion, DefaultSetHolder.DEFAULT_STOP_SET);
+  }
+  
+  /**
+   * Builds an analyzer with the given stop words.
+   * 
+   * @param matchVersion lucene compatibility version
+   * @param stopwords a stopword set
+   */
+  public GalicianAnalyzer(Version matchVersion, Set<?> stopwords) {
+    this(matchVersion, stopwords, CharArraySet.EMPTY_SET);
+  }
+
+  /**
+   * Builds an analyzer with the given stop words. If a non-empty stem exclusion set is
+   * provided this analyzer will add a {@link KeywordMarkerFilter} before
+   * stemming.
+   * 
+   * @param matchVersion lucene compatibility version
+   * @param stopwords a stopword set
+   * @param stemExclusionSet a set of terms not to be stemmed
+   */
+  public GalicianAnalyzer(Version matchVersion, Set<?> stopwords, Set<?> stemExclusionSet) {
+    super(matchVersion, stopwords);
+    this.stemExclusionSet = CharArraySet.unmodifiableSet(CharArraySet.copy(
+        matchVersion, stemExclusionSet));
+  }
+
+  /**
+   * Creates a
+   * {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
+   * which tokenizes all the text in the provided {@link Reader}.
+   * 
+   * @return A
+   *         {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
+   *         built from an {@link StandardTokenizer} filtered with
+   *         {@link StandardFilter}, {@link LowerCaseFilter}, {@link StopFilter}
+   *         , {@link KeywordMarkerFilter} if a stem exclusion set is
+   *         provided and {@link GalicianStemFilter}.
+   */
+  @Override
+  protected TokenStreamComponents createComponents(String fieldName,
+      Reader reader) {
+    final Tokenizer source = new StandardTokenizer(matchVersion, reader);
+    TokenStream result = new StandardFilter(matchVersion, source);
+    result = new LowerCaseFilter(matchVersion, result);
+    result = new StopFilter(matchVersion, result, stopwords);
+    if(!stemExclusionSet.isEmpty())
+      result = new KeywordMarkerFilter(result, stemExclusionSet);
+    result = new GalicianStemFilter(result);
+    return new TokenStreamComponents(source, result);
+  }
+}