pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/el/GreekAnalyzer.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/el/GreekAnalyzer.java
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+package org.apache.lucene.analysis.el;
+
+/**
+ * Copyright 2005 The Apache Software Foundation
+ *
+ * Licensed 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.Analyzer;
+import org.apache.lucene.analysis.StopFilter;
+import org.apache.lucene.analysis.StopwordAnalyzerBase;
+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.standard.StandardAnalyzer;  // for javadoc
+import org.apache.lucene.util.Version;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * {@link Analyzer} for the Greek language. 
+ * <p>
+ * Supports an external list of stopwords (words
+ * that will not be indexed at all).
+ * A default set of stopwords is used unless an alternative list is specified.
+ * </p>
+ *
+ * <a name="version"/>
+ * <p>You must specify the required {@link Version}
+ * compatibility when creating GreekAnalyzer:
+ * <ul>
+ *   <li> As of 3.1, StandardFilter and GreekStemmer are used by default.
+ *   <li> As of 2.9, StopFilter preserves position
+ *        increments
+ * </ul>
+ * 
+ * <p><b>NOTE</b>: This class uses the same {@link Version}
+ * dependent settings as {@link StandardAnalyzer}.</p>
+ */
+public final class GreekAnalyzer extends StopwordAnalyzerBase {
+  /** File containing default Greek stopwords. */
+  public final static String DEFAULT_STOPWORD_FILE = "stopwords.txt";
+  
+  /**
+   * Returns a set of default Greek-stopwords 
+   * @return a set of default Greek-stopwords 
+   */
+  public static final Set<?> getDefaultStopSet(){
+    return DefaultSetHolder.DEFAULT_SET;
+  }
+  
+  private static class DefaultSetHolder {
+    private static final Set<?> DEFAULT_SET;
+    
+    static {
+      try {
+        DEFAULT_SET = loadStopwordSet(false, GreekAnalyzer.class, DEFAULT_STOPWORD_FILE, "#");
+      } 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");
+      }
+    }
+  }
+  
+  /**
+   * Builds an analyzer with the default stop words.
+   * @param matchVersion Lucene compatibility version,
+   *   See <a href="#version">above</a>
+   */
+  public GreekAnalyzer(Version matchVersion) {
+    this(matchVersion, DefaultSetHolder.DEFAULT_SET);
+  }
+  
+  /**
+   * Builds an analyzer with the given stop words. 
+   * <p>
+   * <b>NOTE:</b> The stopwords set should be pre-processed with the logic of 
+   * {@link GreekLowerCaseFilter} for best results.
+   *  
+   * @param matchVersion Lucene compatibility version,
+   *   See <a href="#version">above</a>
+   * @param stopwords a stopword set
+   */
+  public GreekAnalyzer(Version matchVersion, Set<?> stopwords) {
+    super(matchVersion, stopwords);
+  }
+  
+  /**
+   * Builds an analyzer with the given stop words.
+   * @param stopwords Array of stopwords to use.
+   * @deprecated use {@link #GreekAnalyzer(Version, Set)} instead
+   */
+  @Deprecated
+  public GreekAnalyzer(Version matchVersion, String... stopwords) {
+    this(matchVersion, StopFilter.makeStopSet(matchVersion, stopwords));
+  }
+  
+  /**
+   * Builds an analyzer with the given stop words.
+   * @deprecated use {@link #GreekAnalyzer(Version, Set)} instead
+   */
+  @Deprecated
+  public GreekAnalyzer(Version matchVersion, Map<?,?> stopwords) {
+    this(matchVersion, stopwords.keySet());
+  }
+  
+  /**
+   * Creates
+   * {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
+   * used to tokenize all the text in the provided {@link Reader}.
+   * 
+   * @return {@link org.apache.lucene.analysis.ReusableAnalyzerBase.TokenStreamComponents}
+   *         built from a {@link StandardTokenizer} filtered with
+   *         {@link GreekLowerCaseFilter}, {@link StandardFilter},
+   *         {@link StopFilter}, and {@link GreekStemFilter}
+   */
+  @Override
+  protected TokenStreamComponents createComponents(String fieldName,
+      Reader reader) {
+    final Tokenizer source = new StandardTokenizer(matchVersion, reader);
+    TokenStream result = new GreekLowerCaseFilter(matchVersion, source);
+    if (matchVersion.onOrAfter(Version.LUCENE_31))
+      result = new StandardFilter(matchVersion, result);
+    result = new StopFilter(matchVersion, result, stopwords);
+    if (matchVersion.onOrAfter(Version.LUCENE_31))
+      result = new GreekStemFilter(result);
+    return new TokenStreamComponents(source, result);
+  }
+}