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'jdbacl' stands for 'Java DataBase ACcess Layer' and provides utilities for accessing JDBC databases from Java programs, retrieving meta information in an object model and querying database data. 'rapiddweller jdbacl' is forked from Databene jdbacl by Volker Bergmann.

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/*
 * (c) Copyright 2011-2022 by Volker Bergmann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, is permitted under the terms of the
 * GNU General Public License (GPL).
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
 * REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
 * HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package com.rapiddweller.jdbacl;

import com.rapiddweller.common.ExceptionUtil;
import com.rapiddweller.common.exception.ExceptionFactory;
import com.rapiddweller.format.DataIterator;
import com.rapiddweller.format.util.DataIteratorProxy;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * {@link DataIterator} which provides the results of a SQL query.


 * Created: 03.08.2011 19:25:54
 * @author Volker Bergmann
 * @since 0.6.10
 */
public class QueryDataIterator extends DataIteratorProxy {

  private String query;

  public QueryDataIterator(String query, Connection connection, int fetchSize) {
    super(createSource(query, connection, fetchSize));
    this.query = query;
  }

  private static DataIterator createSource(String query, Connection connection, int fetchSize) {
    try {
      int _resultSetHoldability = connection.getMetaData().getResultSetHoldability();
      Statement statement = connection.createStatement(
              ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY, _resultSetHoldability);
      // disable autocommit , there where issues with open resultSets
      connection.setAutoCommit(false);
      statement.setFetchSize(fetchSize);
      ResultSet resultSet = statement.executeQuery(query);
      return new ResultSetDataIterator(resultSet, query);
    } catch (Exception e) {
      throw handleException(query, e);
    }
  }

  private static RuntimeException handleException(String query, Exception e) {
    Throwable root = ExceptionUtil.getRootCause(e);
    String message;
    if (root instanceof SQLException) {
      message = "Error in database query: '" + query + "'";
    } else {
      message = "Error in query: '" + query + "'";
    }
    message += ": " + root.getMessage();
    return ExceptionFactory.getInstance().dbQueryFailed(message, e);
  }

  public String[] getColumnLabels() {
    return ((ResultSetIterator) source).getColumnLabels();
  }

  @Override
  public String toString() {
    return "QueryDataIterator{" + query + '}';
  }

}