/*
    *
    * The DbUnit Database Testing Framework
    * Copyright (C)2002-2004, DbUnit.org
    *
    * This library is free software; you can redistribute it and/or
    * modify it under the terms of the GNU Lesser General Public
    * License as published by the Free Software Foundation; either
    * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   */
  package org.dbunit.dataset;
  
  import org.dbunit.database.QueryTableIterator;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Decorator that allows forward only access to decorated dataset.
   *
   * @author Manuel Laflamme
   * @since Apr 9, 2003
   * @version $Revision$
   */
  public class ForwardOnlyDataSet extends AbstractDataSet
  {
  
      /**
       * Logger for this class
       */
      private static final Logger logger = LoggerFactory.getLogger(ForwardOnlyDataSet.class);
  
      private final IDataSet _dataSet;
      private int _iteratorCount;
  
      public ForwardOnlyDataSet(IDataSet dataSet)
      {
          _dataSet = dataSet;
      }
  
      ////////////////////////////////////////////////////////////////////////////
      // AbstractDataSet class
  
      protected ITableIterator createIterator(boolean reversed)
              throws DataSetException
      {
          logger.debug("createIterator(reversed={}) - start", String.valueOf(reversed));
  
          if (reversed)
          {
              throw new UnsupportedOperationException("Reverse iterator not supported!");
          }
  
          if (_iteratorCount > 0)
          {
              throw new UnsupportedOperationException("Only one iterator allowed!");
          }
  
          return new ForwardOnlyIterator(_dataSet.iterator());
      }
  
      ////////////////////////////////////////////////////////////////////////////
      // IDataSet interface
  
      public String[] getTableNames() throws DataSetException
      {
          throw new UnsupportedOperationException();
      }
  
      public ITableMetaData getTableMetaData(String tableName) throws DataSetException
      {
          throw new UnsupportedOperationException();
      }
  
      public ITable getTable(String tableName) throws DataSetException
      {
          throw new UnsupportedOperationException();
      }
  
      ////////////////////////////////////////////////////////////////////////////
      // ForwardOnlyIterator class
  
      private class ForwardOnlyIterator implements ITableIterator
      {
          private final ITableIterator _iterator;
  
          public ForwardOnlyIterator(ITableIterator iterator)
          {
              _iterator = iterator;
              _iteratorCount++;
         }
 
         ////////////////////////////////////////////////////////////////////////////
         // ITableIterator interface
 
         public boolean next() throws DataSetException
         {
             if(_iterator instanceof QueryTableIterator) {
                 return ((QueryTableIterator) _iterator).nextWithoutClosing();
             } else {
                 return _iterator.next();
             }
         }
 
         public ITableMetaData getTableMetaData() throws DataSetException
         {
             return _iterator.getTableMetaData();
         }
 
         public ITable getTable() throws DataSetException
         {
             return new ForwardOnlyTable(_iterator.getTable());
         }
     }
 }