pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/el/GreekLowerCaseFilter.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/el/GreekLowerCaseFilter.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/el/GreekLowerCaseFilter.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 java.io.IOException;
+
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.util.CharacterUtils;
+import org.apache.lucene.util.Version;
+
+/**
+ * Normalizes token text to lower case, removes some Greek diacritics,
+ * and standardizes final sigma to sigma. 
+ * <a name="version"/>
+ * <p>You must specify the required {@link Version}
+ * compatibility when creating GreekLowerCaseFilter:
+ * <ul>
+ *   <li> As of 3.1, supplementary characters are properly lowercased.
+ * </ul>
+ */
+public final class GreekLowerCaseFilter extends TokenFilter {
+  private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+  private final CharacterUtils charUtils;
+
+  /** @deprecated Use {@link #GreekLowerCaseFilter(Version, TokenStream)} instead. */
+  @Deprecated
+  public GreekLowerCaseFilter(TokenStream in) {
+    this(Version.LUCENE_30, in);
+  }
+  
+  /**
+   * Create a GreekLowerCaseFilter that normalizes Greek token text.
+   * 
+   * @param matchVersion Lucene compatibility version, 
+   *   See <a href="#version">above</a>
+   * @param in TokenStream to filter
+   */
+  public GreekLowerCaseFilter(Version matchVersion, TokenStream in) {
+    super(in);
+    this.charUtils = CharacterUtils.getInstance(matchVersion);
+  }
+  
+  @Override
+  public boolean incrementToken() throws IOException {
+    if (input.incrementToken()) {
+      char[] chArray = termAtt.buffer();
+      int chLen = termAtt.length();
+      for (int i = 0; i < chLen;) {
+        i += Character.toChars(
+            lowerCase(charUtils.codePointAt(chArray, i)), chArray, i);
+       }
+      return true;
+    } else {
+      return false;
+    }
+  }
+  
+  private int lowerCase(int codepoint) {
+    switch(codepoint) {
+      /* There are two lowercase forms of sigma:
+       *   U+03C2: small final sigma (end of word)
+       *   U+03C3: small sigma (otherwise)
+       *   
+       * Standardize both to U+03C3
+       */
+      case '\u03C2': /* small final sigma */
+        return '\u03C3'; /* small sigma */
+        
+      /* Some greek characters contain diacritics.
+       * This filter removes these, converting to the lowercase base form.
+       */
+        
+      case '\u0386': /* capital alpha with tonos */
+      case '\u03AC': /* small alpha with tonos */
+        return '\u03B1'; /* small alpha */
+        
+      case '\u0388': /* capital epsilon with tonos */
+      case '\u03AD': /* small epsilon with tonos */
+        return '\u03B5'; /* small epsilon */
+        
+      case '\u0389': /* capital eta with tonos */
+      case '\u03AE': /* small eta with tonos */
+        return '\u03B7'; /* small eta */
+        
+      case '\u038A': /* capital iota with tonos */
+      case '\u03AA': /* capital iota with dialytika */
+      case '\u03AF': /* small iota with tonos */
+      case '\u03CA': /* small iota with dialytika */
+      case '\u0390': /* small iota with dialytika and tonos */
+        return '\u03B9'; /* small iota */
+        
+      case '\u038E': /* capital upsilon with tonos */
+      case '\u03AB': /* capital upsilon with dialytika */
+      case '\u03CD': /* small upsilon with tonos */
+      case '\u03CB': /* small upsilon with dialytika */
+      case '\u03B0': /* small upsilon with dialytika and tonos */
+        return '\u03C5'; /* small upsilon */
+        
+      case '\u038C': /* capital omicron with tonos */
+      case '\u03CC': /* small omicron with tonos */
+        return '\u03BF'; /* small omicron */
+        
+      case '\u038F': /* capital omega with tonos */
+      case '\u03CE': /* small omega with tonos */
+        return '\u03C9'; /* small omega */
+        
+      /* The previous implementation did the conversion below.
+       * Only implemented for backwards compatibility with old indexes.
+       */
+        
+      case '\u03A2': /* reserved */
+        return '\u03C2'; /* small final sigma */
+        
+      default:
+        return Character.toLowerCase(codepoint);
+    }
+  }
+}