lucene/analysis/common/src/java/org/apache/lucene/analysis/util/ElisionFilterFactory.java

/*
 * 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.util;


import java.io.IOException;
import java.util.Map;

import org.apache.lucene.analysis.CharArraySet;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.fr.FrenchAnalyzer;

/**
 * Factory for {@link ElisionFilter}.
 * <pre class="prettyprint">
 * &lt;fieldType name="text_elsn" class="solr.TextField" positionIncrementGap="100"&gt;
 *   &lt;analyzer&gt;
 *     &lt;tokenizer class="solr.StandardTokenizerFactory"/&gt;
 *     &lt;filter class="solr.LowerCaseFilterFactory"/&gt;
 *     &lt;filter class="solr.ElisionFilterFactory" 
 *       articles="stopwordarticles.txt" ignoreCase="true"/&gt;
 *   &lt;/analyzer&gt;
 * &lt;/fieldType&gt;</pre>
 *
 * @since 3.1
 * @lucene.spi {@value #NAME}
 */
public class ElisionFilterFactory extends TokenFilterFactory implements ResourceLoaderAware {

  /** SPI name */
  public static final String NAME = "elision";

  private final String articlesFile;
  private final boolean ignoreCase;
  private CharArraySet articles;

  /** Creates a new ElisionFilterFactory */
  public ElisionFilterFactory(Map<String,String> args) {
    super(args);
    articlesFile = get(args, "articles");
    ignoreCase = getBoolean(args, "ignoreCase", false);
    if (!args.isEmpty()) {
      throw new IllegalArgumentException("Unknown parameters: " + args);
    }
  }

  @Override
  public void inform(ResourceLoader loader) throws IOException {
    if (articlesFile == null) {
      articles = FrenchAnalyzer.DEFAULT_ARTICLES;
    } else {
      articles = getWordSet(loader, articlesFile, ignoreCase);
    }
  }

  @Override
  public TokenStream create(TokenStream input) {
    return new ElisionFilter(input, articles);
  }

  @Override
  public TokenStream normalize(TokenStream input) {
    return create(input);
  }
}