pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/nl/DutchStemFilter.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/nl/DutchStemFilter.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/nl/DutchStemFilter.java
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+package org.apache.lucene.analysis.nl;
+
+/**
+ * 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.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.lucene.analysis.KeywordMarkerFilter;// for javadoc
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.snowball.SnowballFilter;
+import org.apache.lucene.analysis.tokenattributes.KeywordAttribute;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+
+/**
+ * A {@link TokenFilter} that stems Dutch words. 
+ * <p>
+ * It supports a table of words that should
+ * not be stemmed at all. The stemmer used can be changed at runtime after the
+ * filter object is created (as long as it is a {@link DutchStemmer}).
+ * </p>
+ * <p>
+ * To prevent terms from being stemmed use an instance of
+ * {@link KeywordMarkerFilter} or a custom {@link TokenFilter} that sets
+ * the {@link KeywordAttribute} before this {@link TokenStream}.
+ * </p>
+ * @see KeywordMarkerFilter
+ * @deprecated Use {@link SnowballFilter} with 
+ * {@link org.tartarus.snowball.ext.DutchStemmer} instead, which has the
+ * same functionality. This filter will be removed in Lucene 5.0
+ */
+@Deprecated
+public final class DutchStemFilter extends TokenFilter {
+  /**
+   * The actual token in the input stream.
+   */
+  private DutchStemmer stemmer = new DutchStemmer();
+  private Set<?> exclusions = null;
+  
+  private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+  private final KeywordAttribute keywordAttr = addAttribute(KeywordAttribute.class);
+
+  public DutchStemFilter(TokenStream _in) {
+    super(_in);
+  }
+
+  /**
+   * Builds a DutchStemFilter that uses an exclusion table.
+   * @deprecated use {@link KeywordAttribute} with {@link KeywordMarkerFilter} instead.
+   */
+  @Deprecated
+  public DutchStemFilter(TokenStream _in, Set<?> exclusiontable) {
+    this(_in);
+    exclusions = exclusiontable;
+  }
+  
+  /**
+   * @param stemdictionary Dictionary of word stem pairs, that overrule the algorithm
+   */
+  public DutchStemFilter(TokenStream _in,  Map<?,?> stemdictionary) {
+    this(_in);
+    stemmer.setStemDictionary(stemdictionary);
+  }
+
+  /**
+   * @param stemdictionary Dictionary of word stem pairs, that overrule the algorithm
+   * @deprecated use {@link KeywordAttribute} with {@link KeywordMarkerFilter} instead.
+   */
+  @Deprecated
+  public DutchStemFilter(TokenStream _in, Set<?> exclusiontable, Map<?,?> stemdictionary) {
+    this(_in, exclusiontable);
+    stemmer.setStemDictionary(stemdictionary);
+  }
+
+  /**
+   * Returns the next token in the stream, or null at EOS
+   */
+  @Override
+  public boolean incrementToken() throws IOException {
+    if (input.incrementToken()) {
+      final String term = termAtt.toString();
+
+      // Check the exclusion table.
+      if (!keywordAttr.isKeyword() && (exclusions == null || !exclusions.contains(term))) {
+        final String s = stemmer.stem(term);
+        // If not stemmed, don't waste the time adjusting the token.
+        if ((s != null) && !s.equals(term))
+          termAtt.setEmpty().append(s);
+      }
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  /**
+   * Set a alternative/custom {@link DutchStemmer} for this filter.
+   */
+  public void setStemmer(DutchStemmer stemmer) {
+    if (stemmer != null) {
+      this.stemmer = stemmer;
+    }
+  }
+
+  /**
+   * Set an alternative exclusion list for this filter.
+   * @deprecated use {@link KeywordAttribute} with {@link KeywordMarkerFilter} instead.
+   */
+  @Deprecated
+  public void setExclusionTable(HashSet<?> exclusiontable) {
+    exclusions = exclusiontable;
+  }
+
+  /**
+   * Set dictionary for stemming, this dictionary overrules the algorithm,
+   * so you can correct for a particular unwanted word-stem pair.
+   */
+  public void setStemDictionary(HashMap<?,?> dict) {
+    if (stemmer != null)
+      stemmer.setStemDictionary(dict);
+  }
+}
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