/*
    *
    * 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.operation;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.BitSet;
  
  import org.dbunit.DatabaseUnitException;
  import org.dbunit.database.IDatabaseConnection;
  import org.dbunit.dataset.Column;
  import org.dbunit.dataset.DataSetException;
  import org.dbunit.dataset.IDataSet;
  import org.dbunit.dataset.ITableIterator;
  import org.dbunit.dataset.ITableMetaData;
  import org.dbunit.dataset.NoPrimaryKeyException;
  
  /**
   * Deletes only the dataset contents from the database. This operation does not
   * delete the entire table contents but only data that are present in the
   * dataset.
   *
   * @author Manuel Laflamme
   * @version $Revision$
   * @since Feb 19, 2002
   */
  public class DeleteOperation extends AbstractBatchOperation
  {
  
      /**
       * Logger for this class
       */
      private static final Logger logger = LoggerFactory.getLogger(DeleteOperation.class);
  
      DeleteOperation()
      {
          _reverseRowOrder = true;
      }
  
      ////////////////////////////////////////////////////////////////////////////
      // AbstractBatchOperation class
  
      protected ITableIterator iterator(IDataSet dataSet) throws DatabaseUnitException
      {
          logger.debug("iterator(dataSet={}) - start", dataSet);
          return dataSet.reverseIterator();
      }
  
      public OperationData getOperationData(ITableMetaData metaData, BitSet ignoreMapping, IDatabaseConnection connection) throws DataSetException
      {
      	if (logger.isDebugEnabled())
      	{
      		logger.debug("getOperationData(metaData={}, ignoreMapping={}, connection={}) - start",
      				metaData, ignoreMapping, connection);
      	}
  
          // cannot construct where clause if no primary key
          Column[] primaryKeys = metaData.getPrimaryKeys();
          if (primaryKeys.length == 0)
          {
              throw new NoPrimaryKeyException(metaData.getTableName());
          }
  
          // delete from
          final StringBuilder sqlBuffer = new StringBuilder(128);
          sqlBuffer.append("delete from ");
          sqlBuffer.append(getQualifiedName(connection.getSchema(),
                  metaData.getTableName(), connection));
  
          // where
          sqlBuffer.append(" where ");
          for (int i = 0; i < primaryKeys.length; i++)
          {
              // escape column name
              String columnName = getQualifiedName(null,
                      primaryKeys[i].getColumnName(), connection);
              sqlBuffer.append(columnName);
  
              sqlBuffer.append(" = ?");
             if (i + 1 < primaryKeys.length)
             {
                 sqlBuffer.append(" and ");
             }
         }
 
         return new OperationData(sqlBuffer.toString(), primaryKeys);
     }
 
 }