Package org.apache.lucene.collation

Source Code of org.apache.lucene.collation.ICUCollationKeyFilterFactory

package org.apache.lucene.collation;

/*
* 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.io.Reader;
import java.util.Map;

import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.util.*;
import org.apache.lucene.collation.ICUCollationKeyFilter;
import org.apache.lucene.util.IOUtils;

import com.ibm.icu.text.Collator;
import com.ibm.icu.text.RuleBasedCollator;
import com.ibm.icu.util.ULocale;

/**
* <!-- see LUCENE-4015 for why we cannot link -->
* Factory for <code>ICUCollationKeyFilter</code>.
* <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>locale: RFC 3066 locale ID (mandatory)
<li>strength: 'primary','secondary','tertiary', 'quaternary', or 'identical' (optional)
<li>decomposition: 'no', or 'canonical' (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', 'quaternary', or 'identical' (optional)
<li>decomposition: 'no' or 'canonical' (optional)
* </ul>
* <p>
* Expert options:
* <ul>
<li>alternate: 'shifted' or 'non-ignorable'. Can be used to ignore punctuation/whitespace.
<li>caseLevel: 'true' or 'false'. Useful with strength=primary to ignore accents but not case.
<li>caseFirst: 'lower' or 'upper'. Useful to control which is sorted first when case is not ignored.
<li>numeric: 'true' or 'false'. Digits are sorted according to numeric value, e.g. foobar-9 sorts before foobar-10
<li>variableTop: single character or contraction. Controls what is variable for 'alternate'
* </ul>
*
* @see Collator
* @see ULocale
* @see RuleBasedCollator
* @deprecated use {@link ICUCollationKeyAnalyzer} instead.
*/
@Deprecated
public class ICUCollationKeyFilterFactory extends TokenFilterFactory implements MultiTermAwareComponent, ResourceLoaderAware {
  private Collator collator;
  private final String custom;
  private final String localeID;
  private final String strength;
  private final String decomposition;

  private final String alternate;
  private final String caseLevel;
  private final String caseFirst;
  private final String numeric;
  private final String variableTop;
 
  public ICUCollationKeyFilterFactory(Map<String,String> args) {
    super(args);
    custom = args.remove("custom");
    localeID = args.remove("locale");
    strength = args.remove("strength");
    decomposition = args.remove("decomposition");

    alternate = args.remove("alternate");
    caseLevel = args.remove("caseLevel");
    caseFirst = args.remove("caseFirst");
    numeric = args.remove("numeric");
    variableTop = args.remove("variableTop");
   
    if (custom == null && localeID == null)
      throw new IllegalArgumentException("Either custom or locale is required.");
   
    if (custom != null && localeID != null)
      throw new IllegalArgumentException("Cannot specify both locale 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 (!args.isEmpty()) {
      throw new IllegalArgumentException("Unknown parameters: " + args);
    }
  }

  public void inform(ResourceLoader loader) throws IOException {
    if (localeID != null) {
      // create from a system collator, based on Locale.
      collator = createFromLocale(localeID);
    } 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("quaternary"))
        collator.setStrength(Collator.QUATERNARY);
      else if (strength.equalsIgnoreCase("identical"))
        collator.setStrength(Collator.IDENTICAL);
      else
        throw new IllegalArgumentException("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
        throw new IllegalArgumentException("Invalid decomposition: " + decomposition);
    }
   
    // expert options: concrete subclasses are always a RuleBasedCollator
    RuleBasedCollator rbc = (RuleBasedCollator) collator;
    if (alternate != null) {
      if (alternate.equalsIgnoreCase("shifted")) {
        rbc.setAlternateHandlingShifted(true);
      } else if (alternate.equalsIgnoreCase("non-ignorable")) {
        rbc.setAlternateHandlingShifted(false);
      } else {
        throw new IllegalArgumentException("Invalid alternate: " + alternate);
      }
    }
    if (caseLevel != null) {
      rbc.setCaseLevel(Boolean.parseBoolean(caseLevel));
    }
    if (caseFirst != null) {
      if (caseFirst.equalsIgnoreCase("lower")) {
        rbc.setLowerCaseFirst(true);
      } else if (caseFirst.equalsIgnoreCase("upper")) {
        rbc.setUpperCaseFirst(true);
      } else {
        throw new IllegalArgumentException("Invalid caseFirst: " + caseFirst);
      }
    }
    if (numeric != null) {
      rbc.setNumericCollation(Boolean.parseBoolean(numeric));
    }
    if (variableTop != null) {
      rbc.setVariableTop(variableTop);
    }
  }
 
  public TokenStream create(TokenStream input) {
    return new ICUCollationKeyFilter(input, collator);
  }
 
  /*
   * Create a locale from localeID.
   * Then return the appropriate collator for the locale.
   */
  private Collator createFromLocale(String localeID) {
    return Collator.getInstance(new ULocale(localeID));
  }
 
  /*
   * 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 = toUTF8String(input);
     return new RuleBasedCollator(rules);
    } catch (Exception e) {
      // io error or invalid rules
      throw new RuntimeException(e);
    } finally {
      IOUtils.closeWhileHandlingException(input);
    }
  }
 
  @Override
  public AbstractAnalysisFactory getMultiTermComponent() {
    return this;
  }
 
  private String toUTF8String(InputStream in) throws IOException {
    StringBuilder sb = new StringBuilder();
    char buffer[] = new char[1024];
    Reader r = IOUtils.getDecodingReader(in, IOUtils.CHARSET_UTF_8);
    int len = 0;
    while ((len = r.read(buffer)) > 0) {
      sb.append(buffer, 0, len);
    }
    return sb.toString();
  }
}
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