LetterCase.java

/**
 * Licensed 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.
 *
 * Copyright 2012-2016 the original author or authors.
 */
package org.assertj.db.type.lettercase;

import java.util.HashMap;
import java.util.Map;

/**
 * The letter case which indicates a case conversion and a case comparison.
 * @author Régis Pouiller
 * @since 1.1.0
 */
public class LetterCase implements CaseConversion, CaseComparison {

  /**
   * The default letter case for table.
   */
  public static LetterCase TABLE_DEFAULT = getLetterCase(CaseConversions.NO, CaseComparisons.IGNORE);
  /**
   * The default letter case for table.
   */
  public static LetterCase COLUMN_DEFAULT = getLetterCase(CaseConversions.UPPER, CaseComparisons.IGNORE);
  /**
   * The default letter case for table.
   */
  public static LetterCase PRIMARY_KEY_DEFAULT = getLetterCase(CaseConversions.UPPER, CaseComparisons.IGNORE);

  /**
   * The conversion of the case of a {@link java.lang.String}.
   */
  private CaseConversion conversion;

  /**
   * The comparison on {@link java.lang.String} which consider the case.
   */
  private CaseComparison comparison;

  /**
   * The cache containing the different possible letter case after the first instantiation.
   */
  private static Map<CaseConversion, Map<CaseComparison, LetterCase>> CACHE;

  /**
   * Returns a instance of a letter case.
   * @param conversion The conversion of the case of a {@link java.lang.String}.
   * @param comparison The comparison on {@link java.lang.String} which consider the case.
   * @return An instance of a letter case.
   */
  public static synchronized LetterCase getLetterCase(CaseConversion conversion, CaseComparison comparison) {
    if (conversion == null) {
      throw new NullPointerException("The case conversion must be not null");
    }
    if (comparison == null) {
      throw new NullPointerException("The case comparison must be not null");
    }

    if (CACHE == null) {
      CACHE = new HashMap();
    }
    Map<CaseComparison, LetterCase> map = CACHE.get(conversion);
    if (map == null) {
      map = new HashMap();
      CACHE.put(conversion, map);
      LetterCase letterCase = new LetterCase(conversion, comparison);
      map.put(comparison, letterCase);
      return letterCase;
    }
    LetterCase letterCase = map.get(comparison);
    if (letterCase == null) {
      letterCase = new LetterCase(conversion, comparison);
      map.put(comparison, letterCase);
    }
    return letterCase;
  }

  /**
   * Constructor.
   * @param conversion The conversion of the case of a {@link java.lang.String}.
   * @param comparison The comparison on {@link java.lang.String} which consider the case.
   */
  private LetterCase(CaseConversion conversion, CaseComparison comparison) {
    this.conversion = conversion;
    this.comparison = comparison;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public String getComparisonName() {
    return comparison.getComparisonName();
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public boolean isEqual(String value1, String value2) {
    return comparison.isEqual(value1, value2);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public int compare(String value1, String value2) {
    return comparison.compare(value1, value2);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public String getConversionName() {
    return conversion.getConversionName();
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public String convert(String value) {
    return conversion.convert(value);
  }
}