Kettle代碼解析

Kettle代碼解析

1.添加字段

 /**
   * Adds <code>String</code> value meta with given name if not present and returns index
   *
   * @param rowMeta
   * @param fieldName
   * @return Index in row meta of value meta with <code>fieldName</code>
   */
  public static int addValueMeta( String stepName, RowMetaInterface rowMeta, String fieldName ) {
    ValueMetaInterface valueMeta = new ValueMetaString( fieldName );
    valueMeta.setOrigin( stepName );
    // add if doesn't exist
    int index = -1;
    if ( !rowMeta.exists( valueMeta ) ) {
      index = rowMeta.size();
      rowMeta.addValueMeta( valueMeta );
    } else {
      index = rowMeta.indexOfValue( fieldName );
    }
    return index;
  }