pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/fr/ElisionFilter.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/fr/ElisionFilter.java
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+package org.apache.lucene.analysis.fr;
+
+/**
+ * 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.util.Set;
+import java.util.Arrays;
+import org.apache.lucene.analysis.standard.StandardTokenizer; // for javadocs
+import org.apache.lucene.analysis.CharArraySet;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.util.Version;
+
+/**
+ * Removes elisions from a {@link TokenStream}. For example, "l'avion" (the plane) will be
+ * tokenized as "avion" (plane).
+ * 
+ * @see <a href="http://fr.wikipedia.org/wiki/%C3%89lision">Elision in Wikipedia</a>
+ */
+public final class ElisionFilter extends TokenFilter {
+  private CharArraySet articles = CharArraySet.EMPTY_SET;
+  private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+  private static final CharArraySet DEFAULT_ARTICLES = CharArraySet.unmodifiableSet(
+      new CharArraySet(Version.LUCENE_CURRENT, Arrays.asList(
+          "l", "m", "t", "qu", "n", "s", "j"), true));
+  
+  private static char[] apostrophes = {'\'', '\u2019'};
+  
+  /**
+   * Set the stopword articles
+   * @param matchVersion the lucene backwards compatibility version
+   * @param articles a set of articles
+   * @deprecated use {@link #ElisionFilter(Version, TokenStream, Set)} instead
+   */
+  @Deprecated
+  public void setArticles(Version matchVersion, Set<?> articles) {
+    this.articles = CharArraySet.unmodifiableSet(
+        CharArraySet.copy(matchVersion, articles));
+  }
+
+  /**
+   * Set the stopword articles
+   * @param articles a set of articles
+   * @deprecated use {@link #setArticles(Version, Set)} instead
+   */
+  @Deprecated
+  public void setArticles(Set<?> articles) {
+    setArticles(Version.LUCENE_CURRENT, articles);
+  }
+  /**
+   * Constructs an elision filter with standard stop words
+   */
+  public ElisionFilter(Version matchVersion, TokenStream input) {
+    this(matchVersion, input, DEFAULT_ARTICLES);
+  }
+
+  /**
+   * Constructs an elision filter with standard stop words
+   * @deprecated use {@link #ElisionFilter(Version, TokenStream)} instead
+   */
+  @Deprecated
+  public ElisionFilter(TokenStream input) {
+    this(Version.LUCENE_30, input);
+  }
+
+  /**
+   * Constructs an elision filter with a Set of stop words
+   * @deprecated use {@link #ElisionFilter(Version, TokenStream, Set)} instead
+   */
+  @Deprecated
+  public ElisionFilter(TokenStream input, Set<?> articles) {
+    this(Version.LUCENE_30, input, articles);
+  }
+  
+  /**
+   * Constructs an elision filter with a Set of stop words
+   * @param matchVersion the lucene backwards compatibility version
+   * @param input the source {@link TokenStream}
+   * @param articles a set of stopword articles
+   */
+  public ElisionFilter(Version matchVersion, TokenStream input, Set<?> articles) {
+    super(input);
+    this.articles = CharArraySet.unmodifiableSet(
+        new CharArraySet(matchVersion, articles, true));
+  }
+
+  /**
+   * Constructs an elision filter with an array of stop words
+   * @deprecated use {@link #ElisionFilter(Version, TokenStream, Set)} instead
+   */
+  @Deprecated
+  public ElisionFilter(TokenStream input, String[] articles) {
+    this(Version.LUCENE_CURRENT, input,
+        new CharArraySet(Version.LUCENE_CURRENT,
+            Arrays.asList(articles), true));
+  }
+
+  /**
+   * Increments the {@link TokenStream} with a {@link CharTermAttribute} without elisioned start
+   */
+  @Override
+  public final boolean incrementToken() throws IOException {
+    if (input.incrementToken()) {
+      char[] termBuffer = termAtt.buffer();
+      int termLength = termAtt.length();
+
+      int minPoz = Integer.MAX_VALUE;
+      for (int i = 0; i < apostrophes.length; i++) {
+        char apos = apostrophes[i];
+        // The equivalent of String.indexOf(ch)
+        for (int poz = 0; poz < termLength ; poz++) {
+          if (termBuffer[poz] == apos) {
+            minPoz = Math.min(poz, minPoz);
+            break;
+          }
+        }
+      }
+
+      // An apostrophe has been found. If the prefix is an article strip it off.
+      if (minPoz != Integer.MAX_VALUE
+          && articles.contains(termAtt.buffer(), 0, minPoz)) {
+        termAtt.copyBuffer(termAtt.buffer(), minPoz + 1, termAtt.length() - (minPoz + 1));
+      }
+
+      return true;
+    } else {
+      return false;
+    }
+  }
+}