pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / analysis / StopwordAnalyzerBase.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/analysis/StopwordAnalyzerBase.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/analysis/StopwordAnalyzerBase.java
new file mode 100644 (file)
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/analysis/StopwordAnalyzerBase.java
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+/**
+ * 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.
+ */
+
+package org.apache.lucene.analysis;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.Reader;
+import java.util.Set;
+
+import org.apache.lucene.analysis.CharArraySet;
+import org.apache.lucene.analysis.ReusableAnalyzerBase;
+import org.apache.lucene.analysis.WordlistLoader;
+import org.apache.lucene.util.IOUtils;
+import org.apache.lucene.util.Version;
+
+/**
+ * Base class for Analyzers that need to make use of stopword sets. 
+ * 
+ */
+public abstract class StopwordAnalyzerBase extends ReusableAnalyzerBase {
+
+  /**
+   * An immutable stopword set
+   */
+  protected final CharArraySet stopwords;
+
+  protected final Version matchVersion;
+
+  /**
+   * Returns the analyzer's stopword set or an empty set if the analyzer has no
+   * stopwords
+   * 
+   * @return the analyzer's stopword set or an empty set if the analyzer has no
+   *         stopwords
+   */
+  public Set<?> getStopwordSet() {
+    return stopwords;
+  }
+
+  /**
+   * Creates a new instance initialized with the given stopword set
+   * 
+   * @param version
+   *          the Lucene version for cross version compatibility
+   * @param stopwords
+   *          the analyzer's stopword set
+   */
+  protected StopwordAnalyzerBase(final Version version, final Set<?> stopwords) {
+    matchVersion = version;
+    // analyzers should use char array set for stopwords!
+    this.stopwords = stopwords == null ? CharArraySet.EMPTY_SET : CharArraySet
+        .unmodifiableSet(CharArraySet.copy(version, stopwords));
+  }
+
+  /**
+   * Creates a new Analyzer with an empty stopword set
+   * 
+   * @param version
+   *          the Lucene version for cross version compatibility
+   */
+  protected StopwordAnalyzerBase(final Version version) {
+    this(version, null);
+  }
+
+  /**
+   * Creates a CharArraySet from a file resource associated with a class. (See
+   * {@link Class#getResourceAsStream(String)}).
+   * 
+   * @param ignoreCase
+   *          <code>true</code> if the set should ignore the case of the
+   *          stopwords, otherwise <code>false</code>
+   * @param aClass
+   *          a class that is associated with the given stopwordResource
+   * @param resource
+   *          name of the resource file associated with the given class
+   * @param comment
+   *          comment string to ignore in the stopword file
+   * @return a CharArraySet containing the distinct stopwords from the given
+   *         file
+   * @throws IOException
+   *           if loading the stopwords throws an {@link IOException}
+   */
+  protected static CharArraySet loadStopwordSet(final boolean ignoreCase,
+      final Class<? extends ReusableAnalyzerBase> aClass, final String resource,
+      final String comment) throws IOException {
+    Reader reader = null;
+    try {
+      reader = IOUtils.getDecodingReader(aClass.getResourceAsStream(resource), IOUtils.CHARSET_UTF_8);
+      return WordlistLoader.getWordSet(reader, comment, new CharArraySet(Version.LUCENE_31, 16, ignoreCase));
+    } finally {
+      IOUtils.close(reader);
+    }
+    
+  }
+  
+  /**
+   * Creates a CharArraySet from a file.
+   * 
+   * @param stopwords
+   *          the stopwords file to load
+   * 
+   * @param matchVersion
+   *          the Lucene version for cross version compatibility
+   * @return a CharArraySet containing the distinct stopwords from the given
+   *         file
+   * @throws IOException
+   *           if loading the stopwords throws an {@link IOException}
+   */
+  protected static CharArraySet loadStopwordSet(File stopwords,
+      Version matchVersion) throws IOException {
+    Reader reader = null;
+    try {
+      reader = IOUtils.getDecodingReader(stopwords, IOUtils.CHARSET_UTF_8);
+      return WordlistLoader.getWordSet(reader, matchVersion);
+    } finally {
+      IOUtils.close(reader);
+    }
+  }
+  
+  /**
+   * Creates a CharArraySet from a file.
+   * 
+   * @param stopwords
+   *          the stopwords reader to load
+   * 
+   * @param matchVersion
+   *          the Lucene version for cross version compatibility
+   * @return a CharArraySet containing the distinct stopwords from the given
+   *         reader
+   * @throws IOException
+   *           if loading the stopwords throws an {@link IOException}
+   */
+  protected static CharArraySet loadStopwordSet(Reader stopwords,
+      Version matchVersion) throws IOException {
+    try {
+      return WordlistLoader.getWordSet(stopwords, matchVersion);
+    } finally {
+      IOUtils.close(stopwords);
+    }
+  }
+}