studio.raptor.sqlparser.fast.value.CompareModeIcu4J Maven / Gradle / Ivy

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/*
 * Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package studio.raptor.sqlparser.fast.value;

import java.lang.reflect.Method;
import java.util.Comparator;
import java.util.Locale;
import studio.raptor.sqlparser.fast.message.ParseException;
import studio.raptor.sqlparser.fast.util.JdbcUtils;
import studio.raptor.sqlparser.fast.util.StringUtils;

/**
 * An implementation of CompareMode that uses the ICU4J Collator.
 */
public class CompareModeIcu4J extends CompareMode {

  private final Comparator collator;

  protected CompareModeIcu4J(String name, int strength, boolean binaryUnsigned) {
    super(name, strength, binaryUnsigned);
    collator = getIcu4jCollator(name, strength);
  }

  @SuppressWarnings("unchecked")
  private static Comparator getIcu4jCollator(String name, int strength) {
    try {
      Comparator result = null;
      Class collatorClass = JdbcUtils.loadUserClass(
          "com.ibm.icu.text.Collator");
      Method getInstanceMethod = collatorClass.getMethod(
          "getInstance", Locale.class);
      if (name.length() == 2) {
        Locale locale = new Locale(StringUtils.toLowerEnglish(name), "");
        if (compareLocaleNames(locale, name)) {
          result = (Comparator) getInstanceMethod.invoke(null, locale);
        }
      } else if (name.length() == 5) {
        // LL_CC (language_country)
        int idx = name.indexOf('_');
        if (idx >= 0) {
          String language = StringUtils.toLowerEnglish(name.substring(0, idx));
          String country = name.substring(idx + 1);
          Locale locale = new Locale(language, country);
          if (compareLocaleNames(locale, name)) {
            result = (Comparator) getInstanceMethod.invoke(null, locale);
          }
        }
      }
      if (result == null) {
        for (Locale locale : (Locale[]) collatorClass.getMethod(
            "getAvailableLocales").invoke(null)) {
          if (compareLocaleNames(locale, name)) {
            result = (Comparator) getInstanceMethod.invoke(null, locale);
            break;
          }
        }
      }
      if (result == null) {
        throw ParseException.getInvalidValueException("collator", name);
      }
      collatorClass.getMethod("setStrength", int.class).invoke(result, strength);
      return result;
    } catch (Exception e) {
      throw ParseException.convert(e);
    }
  }

  @Override
  public int compareString(String a, String b, boolean ignoreCase) {
    if (ignoreCase) {
      a = a.toUpperCase();
      b = b.toUpperCase();
    }
    return collator.compare(a, b);
  }

  @Override
  public boolean equalsChars(String a, int ai, String b, int bi,
      boolean ignoreCase) {
    return compareString(a.substring(ai, ai + 1), b.substring(bi, bi + 1),
        ignoreCase) == 0;
  }

}