package com.github.mygreen.supercsv.cellprocessor.conversion;
   
   import org.supercsv.cellprocessor.CellProcessorAdaptor;
   import org.supercsv.cellprocessor.ift.StringCellProcessor;
   import org.supercsv.util.CsvContext;
   
   /**
    * 文字列を切り詰めるCellProcessor
    *
   * @since 2.0
   * @author T.TSUCHIE
   *
   */
  public class Truncate extends CellProcessorAdaptor implements StringCellProcessor{
      
      private final int maxSize;
      private final String suffix;
      
      public Truncate(final int maxSize, final String suffix) {
          super();
          checkPreconditions(maxSize, suffix);
          this.maxSize = maxSize;
          this.suffix = suffix;
      }
      
      public Truncate(final int maxSize, final String suffix, final StringCellProcessor next) {
          super(next);
          checkPreconditions(maxSize, suffix);
          this.maxSize = maxSize;
          this.suffix = suffix;
      }
      
      private static void checkPreconditions(final int maxSize, final String suffix) {
          if( maxSize <= 0 ) {
              throw new IllegalArgumentException(String.format("maxSize should be > 0 but was %d", maxSize));
          }
          
          if( suffix == null ) {
              throw new NullPointerException("suffix should not be null");
          }
      }
      
      @Override
      public <T> T execute(final Object value, final CsvContext context) {
          if(value == null) {
              return next.execute(value, context);
          }
          
          final String stringValue = value.toString();
          final String result;
          if(stringValue.length() <= maxSize) {
              result = stringValue;
          } else {
              result = stringValue.substring(0, maxSize) + suffix;
          }
          
          return next.execute(result, context);
          
      }
      
      /**
       * 最大文字長を取得する。
       * @return 最大文字長
       */
      public int getMaxSize() {
          return maxSize;
      }
      
      /**
       * 接尾語を取得する
       * @return 接尾語
       */
      public String getSuffix() {
          return suffix;
      }
      
  }