/*
    *
    * 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 org.dbunit.DatabaseUnitException;
  import org.dbunit.database.DatabaseConfig;
  import org.dbunit.database.IDatabaseConnection;
  import org.dbunit.database.statement.IBatchStatement;
  import org.dbunit.database.statement.IStatementFactory;
  import org.dbunit.dataset.IDataSet;
  import org.dbunit.dataset.ITableIterator;
  import org.dbunit.dataset.ITableMetaData;
  
  import java.sql.SQLException;
  import java.util.ArrayDeque;
  import java.util.Deque;
  import java.util.HashSet;
  import java.util.Set;
  
  /**
   * Deletes all rows of tables present in the specified dataset. If the dataset
   * does not contains a particular table, but that table exists in the database,
   * the database table is not affected. Table are truncated in
   * reverse sequence.
   * <p/>
   * This operation has the same effect of as {@link TruncateTableOperation}.
   * TruncateTableOperation is faster, and it is non-logged, meaning it cannot be
   * rollback. DeleteAllOperation is more portable because not all database vendor
   * support TRUNCATE_TABLE TABLE statement.
   *
   * @author Manuel Laflamme
   * @version $Revision$
   * @see TruncateTableOperation
   * @since Feb 18, 2002
   */
  public class DeleteAllOperation extends AbstractOperation
  {
  
      /**
       * Logger for this class
       */
      private static final Logger logger = LoggerFactory.getLogger(DeleteAllOperation.class);
  
      DeleteAllOperation()
      {
      }
  
      protected String getDeleteAllCommand()
      {
          return "delete from ";
      }
  
      ////////////////////////////////////////////////////////////////////////////
      // DatabaseOperation class
  
      public void execute(IDatabaseConnection connection, IDataSet dataSet)
              throws DatabaseUnitException, SQLException
      {
          logger.debug("execute(connection={}, dataSet={}) - start", connection, dataSet);
  
          IDataSet databaseDataSet = connection.createDataSet();
  
          DatabaseConfig databaseConfig = connection.getConfig();
          IStatementFactory statementFactory = (IStatementFactory)databaseConfig.getProperty(DatabaseConfig.PROPERTY_STATEMENT_FACTORY);
          IBatchStatement statement = statementFactory.createBatchStatement(connection);
          try
          {
              int count = 0;
              
              final Deque<String> tableNames = new ArrayDeque<>();
              final Set<String> tablesSeen = new HashSet<>();
              ITableIterator iterator = dataSet.iterator();
              while (iterator.next())
              {
                  String tableName = iterator.getTableMetaData().getTableName();
                  if (!tablesSeen.contains(tableName))
                  {
                      tableNames.push(tableName);
                     tablesSeen.add(tableName);
                 }
             }
 
             // delete tables once each in reverse order of seeing them.
             while (!tableNames.isEmpty())
             {
                 String tableName = (String)tableNames.pop();
 
                 // Use database table name. Required to support case sensitive database.
                 ITableMetaData databaseMetaData = databaseDataSet.getTableMetaData(tableName);
                 tableName = databaseMetaData.getTableName();
 
                 final StringBuilder sqlBuffer = new StringBuilder(128);
                 sqlBuffer.append(getDeleteAllCommand());
                 sqlBuffer.append(getQualifiedName(connection.getSchema(), tableName, connection));
                 String sql = sqlBuffer.toString();
                 statement.addBatch(sql);
 
                 if(logger.isDebugEnabled())
                     logger.debug("Added SQL: {}", sql);
                 
                 count++;
             }
 
             if (count > 0)
             {
                 statement.executeBatch();
                 statement.clearBatch();
             }
         }
         finally
         {
             statement.close();
         }
     }
 }