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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 2010-2011 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.model;

import com.rapiddweller.common.HeavyweightIterator;
import com.rapiddweller.common.LogCategoriesConstants;
import com.rapiddweller.jdbacl.DBUtil;
import com.rapiddweller.jdbacl.ResultSetIterator;
import org.slf4j.LoggerFactory;
import org.slf4j.Logger;

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

/**
 * Iterates through the rows of a database.


 * Created: 23.07.2010 07:29:47
 *
 * @author Volker Bergmann
 * @since 0.6.3
 */
public class DBRowIterator implements HeavyweightIterator {

  private static final Logger SQL_LOGGER = LoggerFactory.getLogger(LogCategoriesConstants.SQL);

  private DBTable table;
  private ResultSet resultSet;
  private final ResultSetMetaData resultSetMetaData;
  private final ResultSetIterator resultSetIterator;
  private boolean closed;

  /**
   * Instantiates a new Db row iterator.
   *
   * @param table       the table
   * @param connection  the connection
   * @param whereClause the where clause
   * @throws SQLException the sql exception
   */
  public DBRowIterator(DBTable table, Connection connection, String whereClause) throws SQLException {
    this.table = table;
    String sql = "SELECT * FROM " + table.getName();
    if (whereClause != null) {
      sql += " WHERE " + whereClause;
    }
    SQL_LOGGER.debug(sql);
    Statement statement = connection.createStatement(
        ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY, ResultSet.HOLD_CURSORS_OVER_COMMIT);
    statement.setFetchSize(1000);
    this.resultSet = statement.executeQuery(sql);
    this.resultSetMetaData = resultSet.getMetaData();
    this.resultSetIterator = new ResultSetIterator(resultSet, sql);
    this.closed = false;
  }

  /**
   * With table db row iterator.
   *
   * @param table the table
   * @return the db row iterator
   */
  public DBRowIterator withTable(DBTable table) {
    this.table = table;
    return this;
  }

  @Override
  public boolean hasNext() {
    if (closed) {
      return false;
    }
    boolean result = resultSetIterator.hasNext();
    if (!result) {
      close();
    }
    return result;
  }

  @Override
  public DBRow next() {
    try {
      resultSetIterator.next();
      DBRow row = new DBRow(table);
      int columnCount = resultSetMetaData.getColumnCount();
      for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
        String columnName = resultSetMetaData.getColumnName(columnIndex);
        row.setCellValue(columnName, resultSet.getObject(columnIndex));
      }
      return row;
    } catch (SQLException e) {
      throw new RuntimeException("Error querying table " + table, e);
    }
  }

  @Override
  public void remove() {
    throw new UnsupportedOperationException("remove() is not supported by " + getClass());
  }

  @Override
  public void close() {
    if (!closed) {
      DBUtil.closeResultSetAndStatement(resultSet);
      resultSet = null;
      closed = true;
    }
  }

}