content: /*
   * 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.calcite.jdbc;
  
  import org.apache.calcite.sql.SqlCollation;
  
  import org.checkerframework.checker.initialization.qual.UnderInitialization;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.nio.charset.Charset;
  import java.text.Collator;
  import java.util.Locale;
  
  /**
   * Collation that uses a specific {@link Collator} for comparison.
   */
  public class JavaCollation extends SqlCollation {
    private final Collator collator;
  
    public JavaCollation(Coercibility coercibility, Locale locale, Charset charset, int strength) {
      super(coercibility, locale, charset, getStrengthString(strength));
      collator = Collator.getInstance(locale);
      collator.setStrength(strength);
    }
  
    // Strength values
    private static final String STRENGTH_PRIMARY = "primary";
    private static final String STRENGTH_SECONDARY = "secondary";
    private static final String STRENGTH_TERTIARY = "tertiary";
    private static final String STRENGTH_IDENTICAL = "identical";
  
    private static String getStrengthString(int strengthValue) {
      switch (strengthValue) {
      case Collator.PRIMARY:
        return STRENGTH_PRIMARY;
      case Collator.SECONDARY:
        return STRENGTH_SECONDARY;
      case Collator.TERTIARY:
        return STRENGTH_TERTIARY;
      case Collator.IDENTICAL:
        return STRENGTH_IDENTICAL;
      default:
        throw new IllegalArgumentException("Incorrect strength value.");
      }
    }
  
    @Override protected String generateCollationName(
        @UnderInitialization JavaCollation this,
        Charset charset) {
      return super.generateCollationName(charset) + "$JAVA_COLLATOR";
    }
  
    @Override public @Nullable Collator getCollator() {
      return collator;
    }
  }
  