content: package org.apache.solr.analysis;
  
  /**
   * 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.io.InputStream;
  import java.text.Collator;
  import java.text.ParseException;
  import java.text.RuleBasedCollator;
  import java.util.Locale;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.lucene.analysis.TokenStream;
  import org.apache.lucene.collation.CollationKeyFilter;
  import org.apache.solr.common.ResourceLoader;
  import org.apache.solr.common.SolrException;
  import org.apache.solr.common.SolrException.ErrorCode;
  import org.apache.solr.util.plugin.ResourceLoaderAware;
  
  /**
   * Factory for {@link CollationKeyFilter}.
   * <p>
   * This factory can be created in two ways: 
   * <ul>
   *  <li>Based upon a system collator associated with a Locale.
   *  <li>Based upon a tailored ruleset.
   * </ul>
   * <p>
   * Using a System collator:
   * <ul>
   *  <li>language: ISO-639 language code (mandatory)
   *  <li>country: ISO-3166 country code (optional)
   *  <li>variant: vendor or browser-specific code (optional)
   *  <li>strength: 'primary','secondary','tertiary', or 'identical' (optional)
   *  <li>decomposition: 'no','canonical', or 'full' (optional)
   * </ul>
   * <p>
   * Using a Tailored ruleset:
   * <ul>
   *  <li>custom: UTF-8 text file containing rules supported by RuleBasedCollator (mandatory)
   *  <li>strength: 'primary','secondary','tertiary', or 'identical' (optional)
   *  <li>decomposition: 'no','canonical', or 'full' (optional)
   * </ul>
   * 
   * <pre class="prettyprint" >
   * &lt;fieldType name="text_clltnky" class="solr.TextField" positionIncrementGap="100"&gt;
   *   &lt;analyzer&gt;
   *     &lt;tokenizer class="solr.KeywordTokenizerFactory"/&gt;
   *     &lt;filter class="solr.CollationKeyFilterFactory" language="ja" country="JP"/&gt;
   *   &lt;/analyzer&gt;
   * &lt;/fieldType&gt;</pre>
   * 
   * @see Collator
   * @see Locale
   * @see RuleBasedCollator
   * @since solr 3.1
   */
  public class CollationKeyFilterFactory extends BaseTokenFilterFactory implements ResourceLoaderAware {
    private Collator collator;
  
    public void inform(ResourceLoader loader) {
      String custom = args.get("custom");
      String language = args.get("language");
      String country = args.get("country");
      String variant = args.get("variant");
      String strength = args.get("strength");
      String decomposition = args.get("decomposition");
      
      if (custom == null && language == null)
        throw new SolrException(ErrorCode.SERVER_ERROR, "Either custom or language is required.");
      
      if (custom != null && 
          (language != null || country != null || variant != null))
        throw new SolrException(ErrorCode.SERVER_ERROR, "Cannot specify both language and custom. "
            + "To tailor rules for a built-in language, see the javadocs for RuleBasedCollator. "
            + "Then save the entire customized ruleset to a file, and use with the custom parameter");
      
      if (language != null) { 
        // create from a system collator, based on Locale.
        collator = createFromLocale(language, country, variant);
      } else { 
        // create from a custom ruleset
        collator = createFromRules(custom, loader);
      }
      
      // set the strength flag, otherwise it will be the default.
      if (strength != null) {
        if (strength.equalsIgnoreCase("primary"))
          collator.setStrength(Collator.PRIMARY);
        else if (strength.equalsIgnoreCase("secondary"))
          collator.setStrength(Collator.SECONDARY);
        else if (strength.equalsIgnoreCase("tertiary"))
          collator.setStrength(Collator.TERTIARY);
        else if (strength.equalsIgnoreCase("identical"))
          collator.setStrength(Collator.IDENTICAL);
        else
          throw new SolrException(ErrorCode.SERVER_ERROR, "Invalid strength: " + strength);
      }
      
      // set the decomposition flag, otherwise it will be the default.
      if (decomposition != null) {
        if (decomposition.equalsIgnoreCase("no"))
          collator.setDecomposition(Collator.NO_DECOMPOSITION);
        else if (decomposition.equalsIgnoreCase("canonical"))
          collator.setDecomposition(Collator.CANONICAL_DECOMPOSITION);
        else if (decomposition.equalsIgnoreCase("full"))
          collator.setDecomposition(Collator.FULL_DECOMPOSITION);
        else
          throw new SolrException(ErrorCode.SERVER_ERROR, "Invalid decomposition: " + decomposition);
      }
    }
    
    public TokenStream create(TokenStream input) {
      return new CollationKeyFilter(input, collator);
    }
    
    /*
     * Create a locale from language, with optional country and variant.
     * Then return the appropriate collator for the locale.
     */
    private Collator createFromLocale(String language, String country, String variant) {
      Locale locale;
      
      if (language != null && country == null && variant != null)
        throw new SolrException(ErrorCode.SERVER_ERROR, 
            "To specify variant, country is required");
      else if (language != null && country != null && variant != null)
        locale = new Locale(language, country, variant);
      else if (language != null && country != null)
        locale = new Locale(language, country);
      else 
        locale = new Locale(language);
      
      return Collator.getInstance(locale);
    }
    
    /*
     * Read custom rules from a file, and create a RuleBasedCollator
     * The file cannot support comments, as # might be in the rules!
     */
    private Collator createFromRules(String fileName, ResourceLoader loader) {
      InputStream input = null;
      try {
       input = loader.openResource(fileName);
       String rules = IOUtils.toString(input, "UTF-8");
       return new RuleBasedCollator(rules);
      } catch (IOException e) {
        // io error
        throw new RuntimeException(e);
      } catch (ParseException e) {
        // invalid rules
        throw new RuntimeException(e);
      } finally {
        IOUtils.closeQuietly(input);
      }
    }
  }
  