/*
 Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
 

  The MySQL Connector/J is licensed under the terms of the GPLv2
  <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most MySQL Connectors.
  There are special exceptions to the terms and conditions of the GPLv2 as it is applied to
  this software, see the FLOSS License Exception
  <http://www.mysql.com/about/legal/licensing/foss-exception.html>.

  This program is free software; you can redistribute it and/or modify it under the terms
  of the GNU General Public License as published by the Free Software Foundation; version 2
  of the License.

  This program 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 General Public License for more details.

  You should have received a copy of the GNU General Public License along with this
  program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth
  Floor, Boston, MA 02110-1301  USA



 */
package com.mysql.jdbc;

import java.sql.SQLException;

/**
 * This interface abstracts away how row data is accessed by the result set. It
 * is meant to allow a static implementation (Current version), and a streaming
 * one.
 * 
 * @author dgan
 */
public interface RowData {

	/**
	 * What's returned for the size of a result set when its size can not be
	 * determined.
	 */
	public static final int RESULT_SET_SIZE_UNKNOWN = -1;

	/**
	 * Adds a row to this row data.
	 * 
	 * @param row
	 *            the row to add
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void addRow(ResultSetRow row) throws SQLException;

	/**
	 * Moves to after last.
	 * 
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void afterLast() throws SQLException;

	/**
	 * Moves to before first.
	 * 
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void beforeFirst() throws SQLException;

	/**
	 * Moves to before last so next el is the last el.
	 * 
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void beforeLast() throws SQLException;

	/**
	 * We're done.
	 * 
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void close() throws SQLException;

	/**
	 * Only works on non dynamic result sets.
	 * 
	 * @param index
	 *            row number to get at
	 * @return row data at index
	 * @throws SQLException
	 *             if a database error occurs
	 */
	ResultSetRow getAt(int index) throws SQLException;

	/**
	 * Returns the current position in the result set as a row number.
	 * 
	 * @return the current row number
	 * @throws SQLException
	 *             if a database error occurs
	 */
	int getCurrentRowNumber() throws SQLException;

	/**
	 * Returns the result set that 'owns' this RowData
	 */
	ResultSetInternalMethods getOwner();

	/**
	 * Returns true if another row exsists.
	 * 
	 * @return true if more rows
	 * @throws SQLException
	 *             if a database error occurs
	 */
	boolean hasNext() throws SQLException;

	/**
	 * Returns true if we got the last element.
	 * 
	 * @return true if after last row
	 * @throws SQLException
	 *             if a database error occurs
	 */
	boolean isAfterLast() throws SQLException;

	/**
	 * Returns if iteration has not occured yet.
	 * 
	 * @return true if before first row
	 * @throws SQLException
	 *             if a database error occurs
	 */
	boolean isBeforeFirst() throws SQLException;

	/**
	 * Returns true if the result set is dynamic.
	 * 
	 * This means that move back and move forward won't work because we do not
	 * hold on to the records.
	 * 
	 * @return true if this result set is streaming from the server
	 * @throws SQLException
	 *             if a database error occurs
	 */
	boolean isDynamic() throws SQLException;

	/**
	 * Has no records.
	 * 
	 * @return true if no records
	 * @throws SQLException
	 *             if a database error occurs
	 */
	boolean isEmpty() throws SQLException;

	/**
	 * Are we on the first row of the result set?
	 * 
	 * @return true if on first row
	 * @throws SQLException
	 *             if a database error occurs
	 */
	boolean isFirst() throws SQLException;

	/**
	 * Are we on the last row of the result set?
	 * 
	 * @return true if on last row
	 * @throws SQLException
	 *             if a database error occurs
	 */
	boolean isLast() throws SQLException;

	/**
	 * Moves the current position relative 'rows' from the current position.
	 * 
	 * @param rows
	 *            the relative number of rows to move
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void moveRowRelative(int rows) throws SQLException;

	/**
	 * Returns the next row.
	 * 
	 * @return the next row value
	 * @throws SQLException
	 *             if a database error occurs
	 */
	ResultSetRow next() throws SQLException;

	/**
	 * Removes the row at the given index.
	 * 
	 * @param index
	 *            the row to move to
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void removeRow(int index) throws SQLException;

	/**
	 * Moves the current position in the result set to the given row number.
	 * 
	 * @param rowNumber
	 *            row to move to
	 * @throws SQLException
	 *             if a database error occurs
	 */
	void setCurrentRow(int rowNumber) throws SQLException;

	/**
	 * Set the result set that 'owns' this RowData
	 * 
	 * @param rs
	 *            the result set that 'owns' this RowData
	 */
	void setOwner(ResultSetImpl rs);

	/**
	 * Only works on non dynamic result sets.
	 * 
	 * @return the size of this row data
	 * @throws SQLException
	 *             if a database error occurs
	 */
	int size() throws SQLException;
	
	/**
	 * Did this result set have no rows?
	 */
	boolean wasEmpty();
	
	/**
	 * Sometimes the driver doesn't have metadata until after
	 * the statement has the result set in-hand (because it's cached), 
	 * so it can call this to set it after the fact.
	 * 
	 * @param metadata field-level metadata for the result set
	 */
	void setMetadata(Field[] metadata);
}