package com.github.mygreen.supercsv.cellprocessor.conversion;
   
   import org.supercsv.cellprocessor.CellProcessorAdaptor;
   import org.supercsv.cellprocessor.ift.StringCellProcessor;
   import org.supercsv.util.CsvContext;
   
   /**
    * 全角を半角に変換するCellProcessor。
    * 
   * @since 2.0
   * @author T.TSUCHIE
   *
   */
  public class HalfChar extends CellProcessorAdaptor implements StringCellProcessor {
      
      private final CharCategory[] categories;
      
      private final JapaneseCharReplacer replacer;
      
      public HalfChar(final CharCategory[] categories) {
          super();
          checkPreconditions(categories);
          this.categories = categories;
          this.replacer = new JapaneseCharReplacer(categories);
      }
      
      public HalfChar(final CharCategory[] categories, final StringCellProcessor next) {
          super(next);
          checkPreconditions(categories);
          this.categories = categories;
          this.replacer = new JapaneseCharReplacer(categories);
      }
      
      private static void checkPreconditions(final CharCategory[] categories) {
          if(categories == null) {
              throw new NullPointerException("categories should not be null.");
              
          } else if(categories.length == 0) {
              throw new IllegalArgumentException("categories should not be empty.");
          }
      }
      
      @Override
      public <T> T execute(final Object value, final CsvContext context) {
          
          if(value == null) {
              return next.execute(value, context);
          }
          
          final String result = replacer.replaceToHalfChar(value.toString());
          return next.execute(result, context);
      }
      
      /**
       * 変換対象の文字の種類を取得します。
       * @return コンストラクタで渡した種類です。
       */
      public CharCategory[] getCategories() {
          return categories;
      }
      
  }