/*
  Copyright (c) 2002, 2012, 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.io.InputStream;
import java.math.BigInteger;
import java.sql.BatchUpdateException;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Types;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collections;
import java.util.Enumeration;
import java.util.GregorianCalendar;
import java.util.HashSet;
import java.util.List;
import java.util.Properties;
import java.util.Set;
import java.util.TimerTask;
import java.util.concurrent.atomic.AtomicBoolean;

import com.mysql.jdbc.exceptions.MySQLStatementCancelledException;
import com.mysql.jdbc.exceptions.MySQLTimeoutException;
import com.mysql.jdbc.profiler.ProfilerEvent;
import com.mysql.jdbc.profiler.ProfilerEventHandler;

/**
 * A Statement object is used for executing a static SQL statement and obtaining
 * the results produced by it.
 *
 * <p>
 * Only one ResultSet per Statement can be open at any point in time. Therefore,
 * if the reading of one ResultSet is interleaved with the reading of another,
 * each must have been generated by different Statements. All statement execute
 * methods implicitly close a statement's current ResultSet if an open one
 * exists.
 * </p>
 *
 * @author Mark Matthews
 * @version $Id: Statement.java 4624 2005-11-28 14:24:29 -0600 (Mon, 28 Nov
 *          2005) mmatthews $
 *
 * @see java.sql.Statement
 * @see ResultSetInternalMethods
 */
public class StatementImpl implements Statement {
        protected static final String PING_MARKER = "/* ping */";
	/**
	 * Thread used to implement query timeouts...Eventually we could be more
	 * efficient and have one thread with timers, but this is a straightforward
	 * and simple way to implement a feature that isn't used all that often.
	 */
	class CancelTask extends TimerTask {

		long connectionId = 0;
		String origHost = "";
		SQLException caughtWhileCancelling = null;
		StatementImpl toCancel;
		Properties origConnProps = null; 
		String origConnURL = "";
		
		CancelTask(StatementImpl cancellee) throws SQLException {
			connectionId = cancellee.connectionId;
			origHost = connection.getHost();
			toCancel = cancellee;
			origConnProps = new Properties();
			
			Properties props = connection.getProperties();
			
			Enumeration<?> keys = props.propertyNames();
			
			while (keys.hasMoreElements()) {
				String key = keys.nextElement().toString();
				origConnProps.setProperty(key, props.getProperty(key));
			}
			
			origConnURL = connection.getURL();
		}

		public void run() {

			Thread cancelThread = new Thread() {

				public void run() {
					if (connection.getQueryTimeoutKillsConnection()) {
						try {
							toCancel.wasCancelled = true;
							toCancel.wasCancelledByTimeout = true;
							connection.realClose(false, false, true, 
									new MySQLStatementCancelledException(Messages.getString("Statement.ConnectionKilledDueToTimeout")));
						} catch (NullPointerException npe) {
							// not worth guarding against
						} catch (SQLException sqlEx) {
							caughtWhileCancelling = sqlEx;
						}
					} else {
						Connection cancelConn = null;
						java.sql.Statement cancelStmt = null;
	
						try {
							synchronized (cancelTimeoutMutex) {
								if (origConnURL.equals(connection.getURL())) {
									//All's fine
									cancelConn = connection.duplicate();
									cancelStmt = cancelConn.createStatement();
									cancelStmt.execute("KILL QUERY " + connectionId);
								} else {
									try {
										cancelConn = (Connection) DriverManager.getConnection(origConnURL, origConnProps);
										cancelStmt = cancelConn.createStatement();
										cancelStmt.execute("KILL QUERY " + connectionId);
									} catch (NullPointerException npe){
										//Log this? "Failed to connect to " + origConnURL + " and KILL query"
									}
								}
								toCancel.wasCancelled = true;
								toCancel.wasCancelledByTimeout = true;
							}
						} catch (SQLException sqlEx) {
							caughtWhileCancelling = sqlEx;
						} catch (NullPointerException npe) {
							// Case when connection closed while starting to cancel
							// We can't easily synchronize this, because then one thread
							// can't cancel() a running query
	
							// ignore, we shouldn't re-throw this, because the connection's
							// already closed, so the statement has been timed out.
						} finally {
							if (cancelStmt != null) {
								try {
									cancelStmt.close();
								} catch (SQLException sqlEx) {
									throw new RuntimeException(sqlEx.toString());
								}
							}
	
							if (cancelConn != null) {
								try {
									cancelConn.close();
								} catch (SQLException sqlEx) {
									throw new RuntimeException(sqlEx.toString());
								}
							}
							
							toCancel = null;
							origConnProps = null;
							origConnURL = null;
						}
					}
				}
			};

			cancelThread.start();
		}
	}

	/** Mutex to prevent race between returning query results and noticing
    that we're timed-out or cancelled. */

	protected Object cancelTimeoutMutex = new Object();

	/** Used to generate IDs when profiling. */
	static int statementCounter = 1;

	public final static byte USES_VARIABLES_FALSE = 0;

	public final static byte USES_VARIABLES_TRUE = 1;

	public final static byte USES_VARIABLES_UNKNOWN = -1;

	protected boolean wasCancelled = false;
	protected boolean wasCancelledByTimeout = false;

	/** Holds batched commands */
	protected List<Object> batchedArgs;

	/** The character converter to use (if available) */
	protected SingleByteCharsetConverter charConverter = null;

	/** The character encoding to use (if available) */
	protected String charEncoding = null;

	/** The connection that created us */
	protected volatile MySQLConnection connection = null;

	protected long connectionId = 0;

	/** The catalog in use */
	protected String currentCatalog = null;

	/** Should we process escape codes? */
	protected boolean doEscapeProcessing = true;

	/** If we're profiling, where should events go to? */
	protected ProfilerEventHandler eventSink = null;

	/** The number of rows to fetch at a time (currently ignored) */
	private int fetchSize = 0;

	/** Has this statement been closed? */
	protected boolean isClosed = false;

	/** The auto_increment value for the last insert */
	protected long lastInsertId = -1;

	/** The max field size for this statement */
	protected int maxFieldSize = MysqlIO.getMaxBuf();

	/**
	 * The maximum number of rows to return for this statement (-1 means _all_
	 * rows)
	 */
	protected int maxRows = -1;

	/** Has someone changed this for this statement? */
	protected boolean maxRowsChanged = false;

	/** Set of currently-open ResultSets */
	protected Set<ResultSetInternalMethods> openResults = new HashSet<ResultSetInternalMethods>();

	/** Are we in pedantic mode? */
	protected boolean pedantic = false;

	/**
	 * Where this statement was created, only used if profileSql or
	 * useUsageAdvisor set to true.
	 */
	protected Throwable pointOfOrigin;

	/** Should we profile? */
	protected boolean profileSQL = false;

	/** The current results */
	protected ResultSetInternalMethods results = null;

	/** The concurrency for this result set (updatable or not) */
	protected int resultSetConcurrency = 0;

	/** The type of this result set (scroll sensitive or in-sensitive) */
	protected int resultSetType = 0;

	/** Used to identify this statement when profiling. */
	protected int statementId;

	/** The timeout for a query */
	protected int timeoutInMillis = 0;

	/** The update count for this statement */
	protected long updateCount = -1;

	/** Should we use the usage advisor? */
	protected boolean useUsageAdvisor = false;

	/** The warnings chain. */
	protected SQLWarning warningChain = null;
	
	/** Has clearWarnings() been called? */
	protected boolean clearWarningsCalled = false;

	/**
	 * Should this statement hold results open over .close() irregardless of
	 * connection's setting?
	 */
	protected boolean holdResultsOpenOverClose = false;

	protected ArrayList<ResultSetRow> batchedGeneratedKeys = null;

	protected boolean retrieveGeneratedKeys = false;

	protected boolean continueBatchOnError = false;

	protected PingTarget pingTarget = null;
	
	protected boolean useLegacyDatetimeCode;
	
	private ExceptionInterceptor exceptionInterceptor;
	
	/** Whether or not the last query was of the form ON DUPLICATE KEY UPDATE */
	protected boolean lastQueryIsOnDupKeyUpdate = false;
	
	/** Are we currently executing a statement? */
	protected final AtomicBoolean statementExecuting = new AtomicBoolean(false);
	
	/**
	 * Constructor for a Statement.
	 *
	 * @param c
	 *            the Connection instantation that creates us
	 * @param catalog
	 *            the database name in use when we were created
	 *
	 * @throws SQLException
	 *             if an error occurs.
	 */
	public StatementImpl(MySQLConnection c, String catalog) throws SQLException {
		if ((c == null) || c.isClosed()) {
			throw SQLError.createSQLException(
					Messages.getString("Statement.0"), //$NON-NLS-1$
					SQLError.SQL_STATE_CONNECTION_NOT_OPEN, null); //$NON-NLS-1$ //$NON-NLS-2$
		}

		this.connection = c;
		this.connectionId = this.connection.getId();
		this.exceptionInterceptor = this.connection
				.getExceptionInterceptor();

		this.currentCatalog = catalog;
		this.pedantic = this.connection.getPedantic();
		this.continueBatchOnError = this.connection.getContinueBatchOnError();
		this.useLegacyDatetimeCode = this.connection.getUseLegacyDatetimeCode();
		
		if (!this.connection.getDontTrackOpenResources()) {
			this.connection.registerStatement(this);
		}

		//
		// Adjust, if we know it
		//

		if (this.connection != null) {
			this.maxFieldSize = this.connection.getMaxAllowedPacket();

			int defaultFetchSize = this.connection.getDefaultFetchSize();

			if (defaultFetchSize != 0) {
				setFetchSize(defaultFetchSize);
			}
			
			if (this.connection.getUseUnicode()) {
				this.charEncoding = this.connection.getEncoding();

				this.charConverter = this.connection.getCharsetConverter(this.charEncoding);
			}
			
			

			boolean profiling = this.connection.getProfileSql()
					|| this.connection.getUseUsageAdvisor() || this.connection.getLogSlowQueries();

			if (this.connection.getAutoGenerateTestcaseScript() || profiling) {
				this.statementId = statementCounter++;
			}

			if (profiling) {
				this.pointOfOrigin = new Throwable();
				this.profileSQL = this.connection.getProfileSql();
				this.useUsageAdvisor = this.connection.getUseUsageAdvisor();
				this.eventSink = ProfilerEventHandlerFactory.getInstance(this.connection);
			}

			int maxRowsConn = this.connection.getMaxRows();

			if (maxRowsConn != -1) {
				setMaxRows(maxRowsConn);
			}
			
			this.holdResultsOpenOverClose = this.connection.getHoldResultsOpenOverStatementClose();
		}
		
		version5013OrNewer = this.connection.versionMeetsMinimum(5, 0, 13);
	}

	/**
	 * DOCUMENT ME!
	 *
	 * @param sql
	 *            DOCUMENT ME!
	 *
	 * @throws SQLException
	 *             DOCUMENT ME!
	 */
	public void addBatch(String sql) throws SQLException {
		synchronized (checkClosed()) {
			if (this.batchedArgs == null) {
				this.batchedArgs = new ArrayList<Object>();
			}
	
			if (sql != null) {
				this.batchedArgs.add(sql);
			}
		}
	}

	/** Get the batched args as added by the addBatch method(s).
	 * The list is unmodifiable and might contain any combination of String,
	 * BatchParams, or BatchedBindValues depending on how the parameters were
	 * batched.
	 * @return an unmodifiable List of batched args
	 */
	public List<Object> getBatchedArgs() {
		return batchedArgs==null?null:Collections.unmodifiableList(batchedArgs);
	}

	/**
	 * Cancels this Statement object if both the DBMS and driver support
	 * aborting an SQL statement. This method can be used by one thread to
	 * cancel a statement that is being executed by another thread.
	 */
	public void cancel() throws SQLException {
		if (!this.statementExecuting.get()) {
			return;
		}
		
		if (!this.isClosed &&
				this.connection != null &&
				this.connection.versionMeetsMinimum(5, 0, 0)) {
			Connection cancelConn = null;
			java.sql.Statement cancelStmt = null;

			try {
				cancelConn = this.connection.duplicate();
				cancelStmt = cancelConn.createStatement();
				cancelStmt.execute("KILL QUERY "
						+ this.connection.getIO().getThreadId());
				this.wasCancelled = true;
			} finally {
				if (cancelStmt != null) {
					cancelStmt.close();
				}

				if (cancelConn != null) {
					cancelConn.close();
				}
			}

		}
	}

	// --------------------------JDBC 2.0-----------------------------

	/**
	 * Checks if closed() has been called, and throws an exception if so
	 *
	 * @throws SQLException
	 *             if this statement has been closed
	 */
	protected MySQLConnection checkClosed() throws SQLException {
		MySQLConnection c = this.connection;
		
		if (c == null) {
			throw SQLError.createSQLException(Messages
					.getString("Statement.49"), //$NON-NLS-1$
					SQLError.SQL_STATE_CONNECTION_NOT_OPEN, getExceptionInterceptor()); //$NON-NLS-1$
		}
		
		return c;
	}

	/**
	 * Checks if the given SQL query with the given first non-ws char is a DML
	 * statement. Throws an exception if it is.
	 *
	 * @param sql
	 *            the SQL to check
	 * @param firstStatementChar
	 *            the UC first non-ws char of the statement
	 *
	 * @throws SQLException
	 *             if the statement contains DML
	 */
	protected void checkForDml(String sql, char firstStatementChar)
			throws SQLException {
		if ((firstStatementChar == 'I') || (firstStatementChar == 'U')
				|| (firstStatementChar == 'D') || (firstStatementChar == 'A')
				|| (firstStatementChar == 'C')) {
			String noCommentSql = StringUtils.stripComments(sql,
					"'\"", "'\"", true, false, true, true);

			if (StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "INSERT") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "UPDATE") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "DELETE") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "DROP") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "CREATE") //$NON-NLS-1$
					|| StringUtils.startsWithIgnoreCaseAndWs(noCommentSql, "ALTER")) { //$NON-NLS-1$
				throw SQLError.createSQLException(Messages
						.getString("Statement.57"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}
		}
	}

	/**
	 * Method checkNullOrEmptyQuery.
	 *
	 * @param sql
	 *            the SQL to check
	 *
	 * @throws SQLException
	 *             if query is null or empty.
	 */
	protected void checkNullOrEmptyQuery(String sql) throws SQLException {
		if (sql == null) {
			throw SQLError.createSQLException(Messages
					.getString("Statement.59"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$ //$NON-NLS-2$
		}

		if (sql.length() == 0) {
			throw SQLError.createSQLException(Messages
					.getString("Statement.61"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$ //$NON-NLS-2$
		}
	}

	/**
	 * JDBC 2.0 Make the set of commands in the current batch empty. This method
	 * is optional.
	 *
	 * @exception SQLException
	 *                if a database-access error occurs, or the driver does not
	 *                support batch statements
	 */
	public void clearBatch() throws SQLException {
		synchronized (checkClosed()) {
			if (this.batchedArgs != null) {
				this.batchedArgs.clear();
			}
		}
	}

	/**
	 * After this call, getWarnings returns null until a new warning is reported
	 * for this Statement.
	 *
	 * @exception SQLException
	 *                if a database access error occurs (why?)
	 */
	public void clearWarnings() throws SQLException {
		synchronized (checkClosed()) {
			this.clearWarningsCalled = true;
			this.warningChain = null;
		}
	}

	/**
	 * In many cases, it is desirable to immediately release a Statement's
	 * database and JDBC resources instead of waiting for this to happen when it
	 * is automatically closed. The close method provides this immediate
	 * release.
	 *
	 * <p>
	 * <B>Note:</B> A Statement is automatically closed when it is garbage
	 * collected. When a Statement is closed, its current ResultSet, if one
	 * exists, is also closed.
	 * </p>
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public void close() throws SQLException {
		try {
			synchronized (checkClosed()) {
				realClose(true, true);
			}
		} catch (SQLException sqlEx) {
			if (SQLError.SQL_STATE_CONNECTION_NOT_OPEN.equals(sqlEx.getSQLState())) {
				return;
			}
			
			throw sqlEx;
		}
	}

	/**
	 * Close any open result sets that have been 'held open'
	 */
	protected void closeAllOpenResults() throws SQLException {
		synchronized (checkClosed()) {
			if (this.openResults != null) {
				for (ResultSetInternalMethods element : this.openResults) {
					try {
						element.realClose(false);
					} catch (SQLException sqlEx) {
						AssertionFailedException.shouldNotHappen(sqlEx);
					}
				}
	
				this.openResults.clear();
			}
		}
	}

	public void removeOpenResultSet(ResultSet rs) {
		try {
			synchronized (checkClosed()) {
				if (this.openResults != null) {
					this.openResults.remove(rs);
				}
			}
		} catch (SQLException e) {
			// we can't break the interface, having this be no-op in case of error is ok
		}
	}
	
	public int getOpenResultSetCount() {
		try {
			synchronized (checkClosed()) {
				if (this.openResults != null) {
					return this.openResults.size();
				}
				
				return 0;
			}
		} catch (SQLException e) {
			// we can't break the interface, having this be no-op in case of error is ok
			
			return 0;
		}
	}
	
	/**
	 * @param sql
	 * @return
	 */
	private ResultSetInternalMethods createResultSetUsingServerFetch(String sql)
			throws SQLException {
		synchronized (checkClosed()) {
			java.sql.PreparedStatement pStmt = this.connection.prepareStatement(
					sql, this.resultSetType, this.resultSetConcurrency);
	
			pStmt.setFetchSize(this.fetchSize);
	
			if (this.maxRows > -1) {
				pStmt.setMaxRows(this.maxRows);
			}
	
			statementBegins();
	
			pStmt.execute();
	
			//
			// Need to be able to get resultset irrespective if we issued DML or
			// not to make this work.
			//
			ResultSetInternalMethods rs = ((com.mysql.jdbc.StatementImpl) pStmt)
					.getResultSetInternal();
	
			rs
					.setStatementUsedForFetchingRows((com.mysql.jdbc.PreparedStatement) pStmt);
	
			this.results = rs;
	
			return rs;
		}
	}

	/**
	 * We only stream result sets when they are forward-only, read-only, and the
	 * fetch size has been set to Integer.MIN_VALUE
	 *
	 * @return true if this result set should be streamed row at-a-time, rather
	 *         than read all at once.
	 */
	protected boolean createStreamingResultSet() {
		try {
			synchronized (checkClosed()) {
				return ((this.resultSetType == java.sql.ResultSet.TYPE_FORWARD_ONLY)
						&& (this.resultSetConcurrency == java.sql.ResultSet.CONCUR_READ_ONLY) && (this.fetchSize == Integer.MIN_VALUE));
			}
		} catch (SQLException e) {
			// we can't break the interface, having this be no-op in case of error is ok
			
			return false;
		}
	}

	private int originalResultSetType = 0;
	private int originalFetchSize = 0;

	/* (non-Javadoc)
	 * @see com.mysql.jdbc.IStatement#enableStreamingResults()
	 */
	public void enableStreamingResults() throws SQLException {
		synchronized (checkClosed()) {
			this.originalResultSetType = this.resultSetType;
			this.originalFetchSize = this.fetchSize;
	
			setFetchSize(Integer.MIN_VALUE);
			setResultSetType(ResultSet.TYPE_FORWARD_ONLY);
		}
	}

	public void disableStreamingResults() throws SQLException {
		synchronized (checkClosed()) {
			if (this.fetchSize == Integer.MIN_VALUE &&
					this.resultSetType == ResultSet.TYPE_FORWARD_ONLY) {
				setFetchSize(this.originalFetchSize);
				setResultSetType(this.originalResultSetType);
			}
		}
	}

	/**
	 * Execute a SQL statement that may return multiple results. We don't have
	 * to worry about this since we do not support multiple ResultSets. You can
	 * use getResultSet or getUpdateCount to retrieve the result.
	 *
	 * @param sql
	 *            any SQL statement
	 *
	 * @return true if the next result is a ResulSet, false if it is an update
	 *         count or there are no more results
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public boolean execute(String sql) throws SQLException {
		return execute(sql, false);
	}
	
	private boolean execute(String sql, boolean returnGeneratedKeys) throws SQLException {
		MySQLConnection locallyScopedConn = checkClosed();

		synchronized (locallyScopedConn) {
			this.retrieveGeneratedKeys = returnGeneratedKeys;
			lastQueryIsOnDupKeyUpdate = false;
			if (returnGeneratedKeys)
				lastQueryIsOnDupKeyUpdate = containsOnDuplicateKeyInString(sql);
			
			resetCancelledState();

			checkNullOrEmptyQuery(sql);

			checkClosed();

			char firstNonWsChar = StringUtils.firstAlphaCharUc(sql, findStartOfStatement(sql));

			boolean isSelect = true;

			if (firstNonWsChar != 'S') {
				isSelect = false;

				if (locallyScopedConn.isReadOnly()) {
					throw SQLError.createSQLException(Messages
							.getString("Statement.27") //$NON-NLS-1$
							+ Messages.getString("Statement.28"), //$NON-NLS-1$
							SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
				}
			}

			boolean doStreaming = createStreamingResultSet();

			try {
				// Adjust net_write_timeout to a higher value if we're
				// streaming result sets. More often than not, someone runs into
				// an issue where they blow net_write_timeout when using this
				// feature, and if they're willing to hold a result set open
				// for 30 seconds or more, one more round-trip isn't going to hurt
				//
				// This is reset by RowDataDynamic.close().
	
				if (doStreaming
						&& locallyScopedConn.getNetTimeoutForStreamingResults() > 0) {
					executeSimpleNonQuery(locallyScopedConn, "SET net_write_timeout="
							+ locallyScopedConn.getNetTimeoutForStreamingResults());
				}
	
				if (this.doEscapeProcessing) {
					Object escapedSqlResult = EscapeProcessor.escapeSQL(sql,
							locallyScopedConn.serverSupportsConvertFn(), locallyScopedConn);
	
					if (escapedSqlResult instanceof String) {
						sql = (String) escapedSqlResult;
					} else {
						sql = ((EscapeProcessorResult) escapedSqlResult).escapedSql;
					}
				}
	
				if (this.results != null) {
					if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
						this.results.realClose(false);
					}
				}
	
				if (sql.charAt(0) == '/') {
					if (sql.startsWith(PING_MARKER)) {
						doPingInstead();
					
						return true;
					}
				}
	
				CachedResultSetMetaData cachedMetaData = null;
	
				ResultSetInternalMethods rs = null;
	
				// If there isn't a limit clause in the SQL
				// then limit the number of rows to return in
				// an efficient manner. Only do this if
				// setMaxRows() hasn't been used on any Statements
				// generated from the current Connection (saves
				// a query, and network traffic).
	
				this.batchedGeneratedKeys = null;
	
				if (useServerFetch()) {
					rs = createResultSetUsingServerFetch(sql);
				} else {
					CancelTask timeoutTask = null;
	
					String oldCatalog = null;
	
					try {
						if (locallyScopedConn.getEnableQueryTimeouts() &&
								this.timeoutInMillis != 0
								&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
							timeoutTask = new CancelTask(this);
							locallyScopedConn.getCancelTimer().schedule(timeoutTask,
									this.timeoutInMillis);
						}

						if (!locallyScopedConn.getCatalog().equals(
								this.currentCatalog)) {
							oldCatalog = locallyScopedConn.getCatalog();
							locallyScopedConn.setCatalog(this.currentCatalog);
						}
	
						//
						// Check if we have cached metadata for this query...
						//
	
						Field[] cachedFields = null;
	
						if (locallyScopedConn.getCacheResultSetMetadata()) {
							cachedMetaData = locallyScopedConn.getCachedMetaData(sql);
	
							if (cachedMetaData != null) {
								cachedFields = cachedMetaData.fields;
							}
						}
	
						//
						// Only apply max_rows to selects
						//
						if (locallyScopedConn.useMaxRows()) {
							int rowLimit = -1;
	
							if (isSelect) {
								if (StringUtils.indexOfIgnoreCase(sql, "LIMIT") != -1) { //$NON-NLS-1$
									rowLimit = this.maxRows;
								} else {
									if (this.maxRows <= 0) {
										executeSimpleNonQuery(locallyScopedConn,
												"SET SQL_SELECT_LIMIT=DEFAULT");
									} else {
										executeSimpleNonQuery(locallyScopedConn,
												"SET SQL_SELECT_LIMIT=" + this.maxRows);
									}
								}
							} else {
								executeSimpleNonQuery(locallyScopedConn,
										"SET SQL_SELECT_LIMIT=DEFAULT");
							}
	

							statementBegins();

							// Finally, execute the query
							rs = locallyScopedConn.execSQL(this, sql, rowLimit, null,
									this.resultSetType, this.resultSetConcurrency,
									doStreaming,
									this.currentCatalog, cachedFields);
						} else {
							statementBegins();

							rs = locallyScopedConn.execSQL(this, sql, -1, null,
									this.resultSetType, this.resultSetConcurrency,
									doStreaming,
									this.currentCatalog, cachedFields);
						}
	
						if (timeoutTask != null) {
							if (timeoutTask.caughtWhileCancelling != null) {
								throw timeoutTask.caughtWhileCancelling;
							}
	
							timeoutTask.cancel();
							timeoutTask = null;
						}
	
						synchronized (this.cancelTimeoutMutex) {
							if (this.wasCancelled) {
								SQLException cause = null;
								
								if (this.wasCancelledByTimeout) {
									cause = new MySQLTimeoutException();
								} else {
									cause = new MySQLStatementCancelledException();
								}
								
								resetCancelledState();
								
								throw cause;
							}
						}
					} finally {
						if (timeoutTask != null) {
							timeoutTask.cancel();
							locallyScopedConn.getCancelTimer().purge();
						}
	
						if (oldCatalog != null) {
							locallyScopedConn.setCatalog(oldCatalog);
						}
					}
				}
	
				if (rs != null) {
					this.lastInsertId = rs.getUpdateID();
	
					this.results = rs;
	
					rs.setFirstCharOfQuery(firstNonWsChar);
	
					if (rs.reallyResult()) {
						if (cachedMetaData != null) {
							locallyScopedConn.initializeResultsMetadataFromCache(sql, cachedMetaData,
									this.results);
						} else {
							if (this.connection.getCacheResultSetMetadata()) {
								locallyScopedConn.initializeResultsMetadataFromCache(sql,
										null /* will be created */, this.results);
							}
						}
					}
				}
	
				return ((rs != null) && rs.reallyResult());
			} finally {
				this.statementExecuting.set(false);
			}
		}
	}

	protected void statementBegins() {
		this.clearWarningsCalled = false;
		this.statementExecuting.set(true);
	}

	protected void resetCancelledState() throws SQLException {
		synchronized (checkClosed()) {
			if (this.cancelTimeoutMutex == null) {
				return;
			}
			
			synchronized (this.cancelTimeoutMutex) {
				this.wasCancelled = false;
				this.wasCancelledByTimeout = false;
			}
		}
	}

	/**
	 * @see StatementImpl#execute(String, int)
	 */
	public boolean execute(String sql, int returnGeneratedKeys)
			throws SQLException {


		if (returnGeneratedKeys == java.sql.Statement.RETURN_GENERATED_KEYS) {
			checkClosed();

			MySQLConnection locallyScopedConn = this.connection;

			synchronized (locallyScopedConn) {
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = this.connection
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return execute(sql, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}
		}

		return execute(sql);
	}

	/**
	 * @see StatementImpl#execute(String, int[])
	 */
	public boolean execute(String sql, int[] generatedKeyIndices)
			throws SQLException {
		MySQLConnection locallyScopedConn = checkClosed();

		synchronized (locallyScopedConn) {
			if ((generatedKeyIndices != null) && (generatedKeyIndices.length > 0)) {

				this.retrieveGeneratedKeys = true;
				
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = locallyScopedConn
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return execute(sql, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}
			
			return execute(sql);
		}	
	}

	/**
	 * @see StatementImpl#execute(String, String[])
	 */
	public boolean execute(String sql, String[] generatedKeyNames)
			throws SQLException {
		MySQLConnection locallyScopedConn = checkClosed();

		synchronized (locallyScopedConn) {
			if ((generatedKeyNames != null) && (generatedKeyNames.length > 0)) {

				this.retrieveGeneratedKeys = true;
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = this.connection
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return execute(sql, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}

			return execute(sql);
		}
	}

	/**
	 * JDBC 2.0 Submit a batch of commands to the database for execution. This
	 * method is optional.
	 *
	 * @return an array of update counts containing one element for each command
	 *         in the batch. The array is ordered according to the order in
	 *         which commands were inserted into the batch
	 *
	 * @exception SQLException
	 *                if a database-access error occurs, or the driver does not
	 *                support batch statements
	 * @throws java.sql.BatchUpdateException
	 *             DOCUMENT ME!
	 */
	public int[] executeBatch() throws SQLException {
		MySQLConnection locallyScopedConn = checkClosed();

		synchronized (locallyScopedConn) {
			if (locallyScopedConn.isReadOnly()) {
				throw SQLError.createSQLException(Messages
						.getString("Statement.34") //$NON-NLS-1$
						+ Messages.getString("Statement.35"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}
	
			if (this.results != null) {
				if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
					this.results.realClose(false);
				}
			}

		
			if (this.batchedArgs == null || this.batchedArgs.size() == 0) {
                return new int[0];
            }
			
			// we timeout the entire batch, not individual statements
			int individualStatementTimeout = this.timeoutInMillis;
			this.timeoutInMillis = 0;
			
			CancelTask timeoutTask = null;
			
			try {
				resetCancelledState();

				statementBegins();
				
				try {
					this.retrieveGeneratedKeys = true; // The JDBC spec doesn't forbid this, but doesn't provide for it either...we do..
	
					int[] updateCounts = null;
	
					
					if (this.batchedArgs != null) {
						int nbrCommands = this.batchedArgs.size();
	
						this.batchedGeneratedKeys = new ArrayList<ResultSetRow>(this.batchedArgs.size());
	
						boolean multiQueriesEnabled = locallyScopedConn.getAllowMultiQueries();
	
						if (locallyScopedConn.versionMeetsMinimum(4, 1, 1) &&
								(multiQueriesEnabled ||
								(locallyScopedConn.getRewriteBatchedStatements() &&
										nbrCommands > 4))) {
							return executeBatchUsingMultiQueries(multiQueriesEnabled, nbrCommands, individualStatementTimeout);
						}
	
						if (locallyScopedConn.getEnableQueryTimeouts() &&
								individualStatementTimeout != 0
								&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
							timeoutTask = new CancelTask(this);
							locallyScopedConn.getCancelTimer().schedule(timeoutTask,
									individualStatementTimeout);
						}
						
						updateCounts = new int[nbrCommands];
	
						for (int i = 0; i < nbrCommands; i++) {
							updateCounts[i] = -3;
						}
	
						SQLException sqlEx = null;
	
						int commandIndex = 0;
	
						for (commandIndex = 0; commandIndex < nbrCommands; commandIndex++) {
							try {
								String sql = (String) this.batchedArgs.get(commandIndex);
								updateCounts[commandIndex] = executeUpdate(sql, true, true);
								// limit one generated key per OnDuplicateKey statement
								getBatchedGeneratedKeys(containsOnDuplicateKeyInString(sql) ? 1 : 0);
							} catch (SQLException ex) {
								updateCounts[commandIndex] = EXECUTE_FAILED;
	
								if (this.continueBatchOnError && 
										!(ex instanceof MySQLTimeoutException) && 
										!(ex instanceof MySQLStatementCancelledException) &&
	                                    !hasDeadlockOrTimeoutRolledBackTx(ex)) {
									sqlEx = ex;
								} else {
									int[] newUpdateCounts = new int[commandIndex];
									
									if (hasDeadlockOrTimeoutRolledBackTx(ex)) {
										for (int i = 0; i < newUpdateCounts.length; i++) {
											newUpdateCounts[i] = Statement.EXECUTE_FAILED;
										}
									} else {
										System.arraycopy(updateCounts, 0,
											newUpdateCounts, 0, commandIndex);
									}
	
									throw new java.sql.BatchUpdateException(ex
											.getMessage(), ex.getSQLState(), ex
											.getErrorCode(), newUpdateCounts);
								}
							}
						}
	
						if (sqlEx != null) {
							throw new java.sql.BatchUpdateException(sqlEx
									.getMessage(), sqlEx.getSQLState(), sqlEx
									.getErrorCode(), updateCounts);
						}
					}
	
					if (timeoutTask != null) {
						if (timeoutTask.caughtWhileCancelling != null) {
							throw timeoutTask.caughtWhileCancelling;
						}
	
						timeoutTask.cancel();
						
						locallyScopedConn.getCancelTimer().purge();
						timeoutTask = null;
					}
					
					return (updateCounts != null) ? updateCounts : new int[0];
				} finally {
					this.statementExecuting.set(false);
				}
			} finally {
				
				if (timeoutTask != null) {
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
				}
				
				resetCancelledState();
				
				this.timeoutInMillis = individualStatementTimeout;

				clearBatch();
			}
		}
	}

	protected final boolean hasDeadlockOrTimeoutRolledBackTx(SQLException ex) {
		int vendorCode = ex.getErrorCode();
		
		switch (vendorCode) {
		case MysqlErrorNumbers.ER_LOCK_DEADLOCK:
		case MysqlErrorNumbers.ER_LOCK_TABLE_FULL:
			return true;
		case MysqlErrorNumbers.ER_LOCK_WAIT_TIMEOUT:
				return !version5013OrNewer;
		default:
			return false;
		}
	}

	/**
	 * Rewrites batch into a single query to send to the server. This method
	 * will constrain each batch to be shorter than max_allowed_packet on the
	 * server.
	 *
	 * @return update counts in the same manner as executeBatch()
	 * @throws SQLException
	 */
	private int[] executeBatchUsingMultiQueries(boolean multiQueriesEnabled,
			int nbrCommands, int individualStatementTimeout) throws SQLException {
		
		MySQLConnection locallyScopedConn = checkClosed();

		synchronized (locallyScopedConn) {
			if (!multiQueriesEnabled) {
				locallyScopedConn.getIO().enableMultiQueries();
			}
	
			java.sql.Statement batchStmt = null;
	
			CancelTask timeoutTask = null;
			
			try {
				int[] updateCounts = new int[nbrCommands];
	
				for (int i = 0; i < nbrCommands; i++) {
					updateCounts[i] = -3;
				}
	
				int commandIndex = 0;
	
				StringBuffer queryBuf = new StringBuffer();
	
				batchStmt = locallyScopedConn.createStatement();
	
				if (locallyScopedConn.getEnableQueryTimeouts() &&
						individualStatementTimeout != 0
						&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
					timeoutTask = new CancelTask((StatementImpl)batchStmt);
					locallyScopedConn.getCancelTimer().schedule(timeoutTask,
							individualStatementTimeout);
				}
				
				int counter = 0;
	
				int numberOfBytesPerChar = 1;
	
				String connectionEncoding = locallyScopedConn.getEncoding();
	
				if (StringUtils.startsWithIgnoreCase(connectionEncoding, "utf")) {
					numberOfBytesPerChar = 3;
				} else if (CharsetMapping.isMultibyteCharset(connectionEncoding)) {
					numberOfBytesPerChar = 2;
				}
	
				int escapeAdjust = 1;
	
				batchStmt.setEscapeProcessing(this.doEscapeProcessing);
				
				if (this.doEscapeProcessing) {
					
					escapeAdjust = 2; /* We assume packet _could_ grow by this amount, as we're not
					                     sure how big statement will end up after
					                     escape processing */
				}
	
				SQLException sqlEx = null;
				
				int argumentSetsInBatchSoFar = 0;
				
				for (commandIndex = 0; commandIndex < nbrCommands; commandIndex++) {
					String nextQuery = (String) this.batchedArgs.get(commandIndex);
	
					if (((((queryBuf.length() + nextQuery.length())
							* numberOfBytesPerChar) + 1 /* for semicolon */
							+ MysqlIO.HEADER_LENGTH) * escapeAdjust)  + 32 > this.connection
							.getMaxAllowedPacket()) {
						try {
							batchStmt.execute(queryBuf.toString(), Statement.RETURN_GENERATED_KEYS);
						} catch (SQLException ex) {
							sqlEx = handleExceptionForBatch(commandIndex,
									argumentSetsInBatchSoFar, updateCounts, ex);
						}
	
						counter = processMultiCountsAndKeys((StatementImpl)batchStmt, counter, 
								updateCounts);
	
						queryBuf = new StringBuffer();
						argumentSetsInBatchSoFar = 0;
					}
	
					queryBuf.append(nextQuery);
					queryBuf.append(";");
					argumentSetsInBatchSoFar++;
				}
	
				if (queryBuf.length() > 0) {
					try {
						batchStmt.execute(queryBuf.toString(), Statement.RETURN_GENERATED_KEYS);
					} catch (SQLException ex) {
						sqlEx = handleExceptionForBatch(commandIndex - 1,
								argumentSetsInBatchSoFar, updateCounts, ex);
					}
	
					counter = processMultiCountsAndKeys((StatementImpl)batchStmt, counter, 
							updateCounts);
				}
	
				if (timeoutTask != null) {
					if (timeoutTask.caughtWhileCancelling != null) {
						throw timeoutTask.caughtWhileCancelling;
					}
	
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
					
					timeoutTask = null;
				}
				
				if (sqlEx != null) {
					throw new java.sql.BatchUpdateException(sqlEx
							.getMessage(), sqlEx.getSQLState(), sqlEx
							.getErrorCode(), updateCounts);
				}
				
				return (updateCounts != null) ? updateCounts : new int[0];
			} finally {
				if (timeoutTask != null) {
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
				}
				
				resetCancelledState();
				
				try {
					if (batchStmt != null) {
						batchStmt.close();
					}
				} finally {
					if (!multiQueriesEnabled) {
						locallyScopedConn.getIO().disableMultiQueries();
					}
				}
			}
		}
	}
	
	protected int processMultiCountsAndKeys(
			StatementImpl batchedStatement,
			int updateCountCounter, int[] updateCounts) throws SQLException {
		synchronized (checkClosed()) {
			updateCounts[updateCountCounter++] = batchedStatement.getUpdateCount();
			
			boolean doGenKeys = this.batchedGeneratedKeys != null;
	
			byte[][] row = null;
			
			if (doGenKeys) {
				long generatedKey = batchedStatement.getLastInsertID();
			
				row = new byte[1][];
				row[0] = StringUtils.getBytes(Long.toString(generatedKey));
				this.batchedGeneratedKeys.add(new ByteArrayRow(row, getExceptionInterceptor()));
			}
	
			while (batchedStatement.getMoreResults()
					|| batchedStatement.getUpdateCount() != -1) {
				updateCounts[updateCountCounter++] = batchedStatement.getUpdateCount();
				
				if (doGenKeys) {
					long generatedKey = batchedStatement.getLastInsertID();
					
					row = new byte[1][];
					row[0] = StringUtils.getBytes(Long.toString(generatedKey));
					this.batchedGeneratedKeys.add(new ByteArrayRow(row, getExceptionInterceptor()));
				}
			}
			
			return updateCountCounter;
		}
	}
	
	protected SQLException handleExceptionForBatch(int endOfBatchIndex,
			int numValuesPerBatch, int[] updateCounts, SQLException ex)
			throws BatchUpdateException {
		SQLException sqlEx;
	
		for (int j = endOfBatchIndex; j > endOfBatchIndex - numValuesPerBatch; j--) {
			updateCounts[j] = EXECUTE_FAILED;
		}

		if (this.continueBatchOnError && 
				!(ex instanceof MySQLTimeoutException) && 
				!(ex instanceof MySQLStatementCancelledException) &&
				!hasDeadlockOrTimeoutRolledBackTx(ex)) {
			sqlEx = ex;
		} else {
			int[] newUpdateCounts = new int[endOfBatchIndex];
			System.arraycopy(updateCounts, 0,
					newUpdateCounts, 0, endOfBatchIndex);

			BatchUpdateException batchException = new BatchUpdateException(ex
					.getMessage(), ex.getSQLState(), ex
					.getErrorCode(), newUpdateCounts);
			batchException.initCause(ex);
			throw batchException;
		}
		
		return sqlEx;
	}
	
	/**
	 * Execute a SQL statement that retruns a single ResultSet
	 *
	 * @param sql
	 *            typically a static SQL SELECT statement
	 *
	 * @return a ResulSet that contains the data produced by the query
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public java.sql.ResultSet executeQuery(String sql)
			throws SQLException {
		synchronized (checkClosed()) {
			MySQLConnection locallyScopedConn = this.connection;
			
			this.retrieveGeneratedKeys = false;
			
			resetCancelledState();

			checkNullOrEmptyQuery(sql);

			boolean doStreaming = createStreamingResultSet();

			// Adjust net_write_timeout to a higher value if we're
			// streaming result sets. More often than not, someone runs into
			// an issue where they blow net_write_timeout when using this
			// feature, and if they're willing to hold a result set open
			// for 30 seconds or more, one more round-trip isn't going to hurt
			//
			// This is reset by RowDataDynamic.close().

			if (doStreaming
					&& this.connection.getNetTimeoutForStreamingResults() > 0) {
				executeSimpleNonQuery(locallyScopedConn, "SET net_write_timeout="
						+ this.connection.getNetTimeoutForStreamingResults());
			}

			if (this.doEscapeProcessing) {
				Object escapedSqlResult = EscapeProcessor.escapeSQL(sql,
						locallyScopedConn.serverSupportsConvertFn(), this.connection);

				if (escapedSqlResult instanceof String) {
					sql = (String) escapedSqlResult;
				} else {
					sql = ((EscapeProcessorResult) escapedSqlResult).escapedSql;
				}
			}

			char firstStatementChar = StringUtils.firstNonWsCharUc(sql,
					findStartOfStatement(sql));

			if (sql.charAt(0) == '/') {
				if (sql.startsWith(PING_MARKER)) {
					doPingInstead();
				
					return this.results;
				}
			}
			
			checkForDml(sql, firstStatementChar);

			if (this.results != null) {
				if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
					this.results.realClose(false);
				}
			}

			CachedResultSetMetaData cachedMetaData = null;

			// If there isn't a limit clause in the SQL
			// then limit the number of rows to return in
			// an efficient manner. Only do this if
			// setMaxRows() hasn't been used on any Statements
			// generated from the current Connection (saves
			// a query, and network traffic).

			if (useServerFetch()) {
				this.results = createResultSetUsingServerFetch(sql);

				return this.results;
			}

			CancelTask timeoutTask = null;

			String oldCatalog = null;

			try {
				if (locallyScopedConn.getEnableQueryTimeouts() &&
						this.timeoutInMillis != 0
						&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
					timeoutTask = new CancelTask(this);
					locallyScopedConn.getCancelTimer().schedule(timeoutTask,
							this.timeoutInMillis);
				}

				if (!locallyScopedConn.getCatalog().equals(this.currentCatalog)) {
					oldCatalog = locallyScopedConn.getCatalog();
					locallyScopedConn.setCatalog(this.currentCatalog);
				}

				//
				// Check if we have cached metadata for this query...
				//

				Field[] cachedFields = null;

				if (locallyScopedConn.getCacheResultSetMetadata()) {
					cachedMetaData = locallyScopedConn.getCachedMetaData(sql);

					if (cachedMetaData != null) {
						cachedFields = cachedMetaData.fields;
					}
				}

				if (locallyScopedConn.useMaxRows()) {
					// We need to execute this all together
					// So synchronize on the Connection's mutex (because
					// even queries going through there synchronize
					// on the connection
					if (StringUtils.indexOfIgnoreCase(sql, "LIMIT") != -1) { //$NON-NLS-1$
						this.results = locallyScopedConn.execSQL(this, sql,
								this.maxRows, null, this.resultSetType,
								this.resultSetConcurrency,
								doStreaming,
								this.currentCatalog, cachedFields);
					} else {
						if (this.maxRows <= 0) {
							executeSimpleNonQuery(locallyScopedConn,
									"SET SQL_SELECT_LIMIT=DEFAULT");
						} else {
							executeSimpleNonQuery(locallyScopedConn,
									"SET SQL_SELECT_LIMIT=" + this.maxRows);
						}

						statementBegins();
						
						this.results = locallyScopedConn.execSQL(this, sql, -1,
								null, this.resultSetType,
								this.resultSetConcurrency,
								doStreaming,
								this.currentCatalog, cachedFields);

						if (oldCatalog != null) {
							locallyScopedConn.setCatalog(oldCatalog);
						}
					}
				} else {
					statementBegins();
					
					this.results = locallyScopedConn.execSQL(this, sql, -1, null,
							this.resultSetType, this.resultSetConcurrency,
							doStreaming,
							this.currentCatalog, cachedFields);
				}

				if (timeoutTask != null) {
					if (timeoutTask.caughtWhileCancelling != null) {
						throw timeoutTask.caughtWhileCancelling;
					}

					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
					
					timeoutTask = null;
				}

				synchronized (this.cancelTimeoutMutex) {
					if (this.wasCancelled) {
						SQLException cause = null;
						
						if (this.wasCancelledByTimeout) {
							cause = new MySQLTimeoutException();
						} else {
							cause = new MySQLStatementCancelledException();
						}
						
						resetCancelledState();
						
						throw cause;
					}
				}
			} finally {
				this.statementExecuting.set(false);
				
				if (timeoutTask != null) {
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
				}

				if (oldCatalog != null) {
					locallyScopedConn.setCatalog(oldCatalog);
				}
			}

			this.lastInsertId = this.results.getUpdateID();

			if (cachedMetaData != null) {
				locallyScopedConn.initializeResultsMetadataFromCache(sql, cachedMetaData,
						this.results);
			} else {
				if (this.connection.getCacheResultSetMetadata()) {
					locallyScopedConn.initializeResultsMetadataFromCache(sql,
							null /* will be created */, this.results);
				}
			}

			return this.results;
		}
	}

	protected void doPingInstead() throws SQLException {
		synchronized (checkClosed()) {
			if (this.pingTarget != null) {
				this.pingTarget.doPing();
			} else {
				this.connection.ping();
			}
	
			ResultSetInternalMethods fakeSelectOneResultSet = generatePingResultSet();
			this.results = fakeSelectOneResultSet;
		}
	}

	protected ResultSetInternalMethods generatePingResultSet() throws SQLException {
		synchronized (checkClosed()) {
			Field[] fields = { new Field(null, "1", Types.BIGINT, 1) };
			ArrayList<ResultSetRow> rows = new ArrayList<ResultSetRow>();
			byte[] colVal = new byte[] { (byte) '1' };
	
			rows.add(new ByteArrayRow(new byte[][] { colVal }, getExceptionInterceptor()));
	
			return (ResultSetInternalMethods) DatabaseMetaData.buildResultSet(fields, rows,
					this.connection);
		}
	}
	
	protected void executeSimpleNonQuery(MySQLConnection c, String nonQuery)
			throws SQLException {
		c.execSQL(this, nonQuery,
				-1, null, ResultSet.TYPE_FORWARD_ONLY,
				ResultSet.CONCUR_READ_ONLY, false, this.currentCatalog,
				null, false).close();
	}

	/**
	 * Execute a SQL INSERT, UPDATE or DELETE statement. In addition SQL
	 * statements that return nothing such as SQL DDL statements can be executed
	 * Any IDs generated for AUTO_INCREMENT fields can be retrieved by casting
	 * this Statement to org.gjt.mm.mysql.Statement and calling the
	 * getLastInsertID() method.
	 *
	 * @param sql
	 *            a SQL statement
	 *
	 * @return either a row count, or 0 for SQL commands
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public int executeUpdate(String sql) throws SQLException {
		return executeUpdate(sql, false, false);
	}

	protected int executeUpdate(String sql, boolean isBatch, boolean returnGeneratedKeys)
		throws SQLException {
		
		synchronized (checkClosed()) {
			MySQLConnection locallyScopedConn = this.connection;
	
			char firstStatementChar = StringUtils.firstAlphaCharUc(sql,
					findStartOfStatement(sql));
	
			ResultSetInternalMethods rs = null;
		
			this.retrieveGeneratedKeys = returnGeneratedKeys;
			
			resetCancelledState();

			checkNullOrEmptyQuery(sql);

			if (this.doEscapeProcessing) {
				Object escapedSqlResult = EscapeProcessor.escapeSQL(sql,
						this.connection.serverSupportsConvertFn(), this.connection);

				if (escapedSqlResult instanceof String) {
					sql = (String) escapedSqlResult;
				} else {
					sql = ((EscapeProcessorResult) escapedSqlResult).escapedSql;
				}
			}

			if (locallyScopedConn.isReadOnly()) {
				throw SQLError.createSQLException(Messages
						.getString("Statement.42") //$NON-NLS-1$
						+ Messages.getString("Statement.43"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}

			if (StringUtils.startsWithIgnoreCaseAndWs(sql, "select")) { //$NON-NLS-1$
				throw SQLError.createSQLException(Messages
						.getString("Statement.46"), //$NON-NLS-1$
				"01S03", getExceptionInterceptor()); //$NON-NLS-1$
			}

			if (this.results != null) {
				if (!locallyScopedConn.getHoldResultsOpenOverStatementClose()) {
					this.results.realClose(false);
				}
			}

			// The checking and changing of catalogs
			// must happen in sequence, so synchronize
			// on the same mutex that _conn is using

			CancelTask timeoutTask = null;

			String oldCatalog = null;

			try {
				if (locallyScopedConn.getEnableQueryTimeouts() &&
						this.timeoutInMillis != 0
						&& locallyScopedConn.versionMeetsMinimum(5, 0, 0)) {
					timeoutTask = new CancelTask(this);
					locallyScopedConn.getCancelTimer().schedule(timeoutTask,
							this.timeoutInMillis);
				}

				if (!locallyScopedConn.getCatalog().equals(this.currentCatalog)) {
					oldCatalog = locallyScopedConn.getCatalog();
					locallyScopedConn.setCatalog(this.currentCatalog);
				}

				//
				// Only apply max_rows to selects
				//
				if (locallyScopedConn.useMaxRows()) {
					executeSimpleNonQuery(locallyScopedConn,
							"SET SQL_SELECT_LIMIT=DEFAULT");
				}

				statementBegins();
				
				rs = locallyScopedConn.execSQL(this, sql, -1, null,
						java.sql.ResultSet.TYPE_FORWARD_ONLY,
						java.sql.ResultSet.CONCUR_READ_ONLY, false,
						this.currentCatalog,
						null /* force read of field info on DML */,
						isBatch);

				if (timeoutTask != null) {
					if (timeoutTask.caughtWhileCancelling != null) {
						throw timeoutTask.caughtWhileCancelling;
					}

					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
					
					timeoutTask = null;
				}

				synchronized (this.cancelTimeoutMutex) {
					if (this.wasCancelled) {
						SQLException cause = null;
						
						if (this.wasCancelledByTimeout) {
							cause = new MySQLTimeoutException();
						} else {
							cause = new MySQLStatementCancelledException();
						}
						
						resetCancelledState();
						
						throw cause;
					}
				}
			} finally {
				if (timeoutTask != null) {
					timeoutTask.cancel();
					
					locallyScopedConn.getCancelTimer().purge();
				}

				if (oldCatalog != null) {
					locallyScopedConn.setCatalog(oldCatalog);
				}
				
				if (!isBatch) {
					this.statementExecuting.set(false);
				}
			}
			
			this.results = rs;

			rs.setFirstCharOfQuery(firstStatementChar);

			this.updateCount = rs.getUpdateCount();

			int truncatedUpdateCount = 0;

			if (this.updateCount > Integer.MAX_VALUE) {
				truncatedUpdateCount = Integer.MAX_VALUE;
			} else {
				truncatedUpdateCount = (int) this.updateCount;
			}

			this.lastInsertId = rs.getUpdateID();

			return truncatedUpdateCount;
		}
	}


	/**
	 * @see StatementImpl#executeUpdate(String, int)
	 */
	public int executeUpdate(String sql, int returnGeneratedKeys)
			throws SQLException {
		synchronized (checkClosed()) {
			if (returnGeneratedKeys == java.sql.Statement.RETURN_GENERATED_KEYS) {
				MySQLConnection locallyScopedConn = this.connection;
			
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = locallyScopedConn
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return executeUpdate(sql, false, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}
			
			return executeUpdate(sql);
		}
	}

	/**
	 * @see StatementImpl#executeUpdate(String, int[])
	 */
	public int executeUpdate(String sql, int[] generatedKeyIndices)
			throws SQLException {
		synchronized (checkClosed()) {
			if ((generatedKeyIndices != null) && (generatedKeyIndices.length > 0)) {
				checkClosed();
	
				MySQLConnection locallyScopedConn = this.connection;
				
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = locallyScopedConn
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return executeUpdate(sql, false, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}
			
			return executeUpdate(sql);
		}
	}

	/**
	 * @see StatementImpl#executeUpdate(String, String[])
	 */
	public int executeUpdate(String sql, String[] generatedKeyNames)
			throws SQLException {
		synchronized (checkClosed()) {
			if ((generatedKeyNames != null) && (generatedKeyNames.length > 0)) {
				MySQLConnection locallyScopedConn = this.connection;
				// If this is a 'REPLACE' query, we need to be able to parse
				// the 'info' message returned from the server to determine
				// the actual number of keys generated.
				boolean readInfoMsgState = this.connection
						.isReadInfoMsgEnabled();
				locallyScopedConn.setReadInfoMsgEnabled(true);

				try {
					return executeUpdate(sql, false, true);
				} finally {
					locallyScopedConn.setReadInfoMsgEnabled(readInfoMsgState);
				}
			}	

			return executeUpdate(sql);
		}
	}

	/**
	 * Optimization to only use one calendar per-session, or calculate it for
	 * each call, depending on user configuration
	 */
	protected Calendar getCalendarInstanceForSessionOrNew() throws SQLException {
		synchronized (checkClosed()) {
			if (this.connection != null) {
				return this.connection.getCalendarInstanceForSessionOrNew();
			}
			// punt, no connection around
			return new GregorianCalendar();
		}
	}

	/**
	 * JDBC 2.0 Return the Connection that produced the Statement.
	 *
	 * @return the Connection that produced the Statement
	 *
	 * @throws SQLException
	 *             if an error occurs
	 */
	public java.sql.Connection getConnection() throws SQLException {
		synchronized (checkClosed()) {
			return this.connection;
		}
	}

	/**
	 * JDBC 2.0 Determine the fetch direction.
	 *
	 * @return the default fetch direction
	 *
	 * @exception SQLException
	 *                if a database-access error occurs
	 */
	public int getFetchDirection() throws SQLException {
		return java.sql.ResultSet.FETCH_FORWARD;
	}

	/**
	 * JDBC 2.0 Determine the default fetch size.
	 *
	 * @return the number of rows to fetch at a time
	 *
	 * @throws SQLException
	 *             if an error occurs
	 */
	public int getFetchSize() throws SQLException {
		synchronized (checkClosed()) {
			return this.fetchSize;
		}
	}

	/**
	 * DOCUMENT ME!
	 *
	 * @return DOCUMENT ME!
	 *
	 * @throws SQLException
	 *             DOCUMENT ME!
	 */
	public java.sql.ResultSet getGeneratedKeys()
			throws SQLException {
		synchronized (checkClosed()) {
			if (!this.retrieveGeneratedKeys) {
				throw SQLError.createSQLException(Messages.getString("Statement.GeneratedKeysNotRequested"), SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor());
			}
			
			if (this.batchedGeneratedKeys == null) {
				if (lastQueryIsOnDupKeyUpdate) {
					return getGeneratedKeysInternal(1);
				}
				return getGeneratedKeysInternal();
			}
	
			Field[] fields = new Field[1];
			fields[0] = new Field("", "GENERATED_KEY", Types.BIGINT, 17); //$NON-NLS-1$ //$NON-NLS-2$
			fields[0].setConnection(this.connection);
	
			return com.mysql.jdbc.ResultSetImpl.getInstance(this.currentCatalog, fields,
					new RowDataStatic(this.batchedGeneratedKeys), this.connection,
					this, false);
		}
	}

	/*
	 * Needed because there's no concept of super.super to get to this
	 * implementation from ServerPreparedStatement when dealing with batched
	 * updates.
	 */
	protected java.sql.ResultSet getGeneratedKeysInternal()
			throws SQLException {
		int numKeys = getUpdateCount();
		return getGeneratedKeysInternal(numKeys);
	}

	protected java.sql.ResultSet getGeneratedKeysInternal(int numKeys)
			throws SQLException {
		synchronized (checkClosed()) {
			Field[] fields = new Field[1];
			fields[0] = new Field("", "GENERATED_KEY", Types.BIGINT, 17); //$NON-NLS-1$ //$NON-NLS-2$
			fields[0].setConnection(this.connection);
			fields[0].setUseOldNameMetadata(true);
	
			ArrayList<ResultSetRow> rowSet = new ArrayList<ResultSetRow>();
	
			long beginAt = getLastInsertID();
			
			if (beginAt < 0) { // looking at an UNSIGNED BIGINT that has overflowed
				fields[0].setUnsigned();
			}
	
			if (this.results != null) {
				String serverInfo = this.results.getServerInfo();
	
				//
				// Only parse server info messages for 'REPLACE'
				// queries
				//
				if ((numKeys > 0) && (this.results.getFirstCharOfQuery() == 'R')
						&& (serverInfo != null) && (serverInfo.length() > 0)) {
					numKeys = getRecordCountFromInfo(serverInfo);
				}
	
				if ((beginAt != 0 /* BIGINT UNSIGNED can wrap the protocol representation */) && (numKeys > 0)) {
					for (int i = 0; i < numKeys; i++) {
						byte[][] row = new byte[1][];
						if (beginAt > 0) {
							row[0] = StringUtils.getBytes(Long.toString(beginAt));
						} else {
							byte[] asBytes = new byte[8];
							asBytes[7] = (byte) (beginAt & 0xff);
							asBytes[6] = (byte) (beginAt >>> 8);
							asBytes[5] = (byte) (beginAt >>> 16);
							asBytes[4] = (byte) (beginAt >>> 24);
							asBytes[3] = (byte) (beginAt >>> 32);
							asBytes[2] = (byte) (beginAt >>> 40);
							asBytes[1] = (byte) (beginAt >>> 48);
							asBytes[0] = (byte) (beginAt >>> 56);
							
							BigInteger val = new BigInteger(1, asBytes);
	
							row[0] = val.toString().getBytes();
						}
						rowSet.add(new ByteArrayRow(row, getExceptionInterceptor()));
						beginAt  += this.connection.getAutoIncrementIncrement();
					}
				}
			}
			
			com.mysql.jdbc.ResultSetImpl gkRs = com.mysql.jdbc.ResultSetImpl.getInstance(this.currentCatalog, fields,
					new RowDataStatic(rowSet), this.connection, this, false);
			
			this.openResults.add(gkRs);
			
			return gkRs;
		}
	}

	/**
	 * Returns the id used when profiling
	 *
	 * @return the id used when profiling.
	 */
	protected int getId() {
		return this.statementId;
	}

	/**
	 * getLastInsertID returns the value of the auto_incremented key after an
	 * executeQuery() or excute() call.
	 *
	 * <p>
	 * This gets around the un-threadsafe behavior of "select LAST_INSERT_ID()"
	 * which is tied to the Connection that created this Statement, and
	 * therefore could have had many INSERTS performed before one gets a chance
	 * to call "select LAST_INSERT_ID()".
	 * </p>
	 *
	 * @return the last update ID.
	 */
	public long getLastInsertID() {
		try {
			synchronized (checkClosed()) {
				return this.lastInsertId;
			}
		} catch (SQLException e) {
			throw new RuntimeException(e); // evolve interface to throw SQLException
		}
	}

	/**
	 * getLongUpdateCount returns the current result as an update count, if the
	 * result is a ResultSet or there are no more results, -1 is returned. It
	 * should only be called once per result.
	 *
	 * <p>
	 * This method returns longs as MySQL server versions newer than 3.22.4
	 * return 64-bit values for update counts
	 * </p>
	 *
	 * @return the current update count.
	 */
	public long getLongUpdateCount() {
		try {
			synchronized (checkClosed()) {
				if (this.results == null) {
					return -1;
				}

				if (this.results.reallyResult()) {
					return -1;
				}

				return this.updateCount;
			}
		} catch (SQLException e) {
			throw new RuntimeException(e); // evolve interface to throw SQLException
		}
	}

	/**
	 * The maxFieldSize limit (in bytes) is the maximum amount of data returned
	 * for any column value; it only applies to BINARY, VARBINARY,
	 * LONGVARBINARY, CHAR, VARCHAR and LONGVARCHAR columns. If the limit is
	 * exceeded, the excess data is silently discarded.
	 *
	 * @return the current max column size limit; zero means unlimited
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public int getMaxFieldSize() throws SQLException {
		synchronized (checkClosed()) {
			return this.maxFieldSize;
		}
	}

	/**
	 * The maxRows limit is set to limit the number of rows that any ResultSet
	 * can contain. If the limit is exceeded, the excess rows are silently
	 * dropped.
	 *
	 * @return the current maximum row limit; zero means unlimited
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public int getMaxRows() throws SQLException {
		synchronized (checkClosed()) {
			if (this.maxRows <= 0) {
				return 0;
			}

			return this.maxRows;
		}
	}

	/**
	 * getMoreResults moves to a Statement's next result. If it returns true,
	 * this result is a ResulSet.
	 *
	 * @return true if the next ResultSet is valid
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public boolean getMoreResults() throws SQLException {
		return getMoreResults(CLOSE_CURRENT_RESULT);
	}

	/**
	 * @see StatementImpl#getMoreResults(int)
	 */
	public boolean getMoreResults(int current) throws SQLException {
		synchronized (checkClosed()) {
			if (this.results == null) {
				return false;
			}
	
			boolean streamingMode = createStreamingResultSet();
			
			if (streamingMode) {
				if (this.results.reallyResult()) {
					while (this.results.next()); // need to drain remaining rows to get to server status 
											 // which tells us whether more results actually exist or not
				}
			}
			
			ResultSetInternalMethods nextResultSet = this.results.getNextResultSet();
	
			switch (current) {
			case java.sql.Statement.CLOSE_CURRENT_RESULT:
	
				if (this.results != null) {
					if (!streamingMode) { 
						this.results.close();
					}
					
					this.results.clearNextResult();
				}
	
				break;
	
			case java.sql.Statement.CLOSE_ALL_RESULTS:
	
				if (this.results != null) {
					if (!streamingMode) { 
						this.results.close();
					}
					
					this.results.clearNextResult();
				}
	
				closeAllOpenResults();
	
				break;
	
			case java.sql.Statement.KEEP_CURRENT_RESULT:
				if (!this.connection.getDontTrackOpenResources()) {
					this.openResults.add(this.results);
				}
	
				this.results.clearNextResult(); // nobody besides us should
				// ever need this value...
				break;
	
			default:
				throw SQLError.createSQLException(Messages
						.getString("Statement.19"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}
	
			this.results = nextResultSet;
	
			if (this.results == null) {
				this.updateCount = -1;
				this.lastInsertId = -1;
			} else if (this.results.reallyResult()) {
				this.updateCount = -1;
				this.lastInsertId = -1;
			} else {
				this.updateCount = this.results.getUpdateCount();
				this.lastInsertId = this.results.getUpdateID();
			}
	
			return ((this.results != null) && this.results.reallyResult()) ? true
					: false;
		}
	}

	/**
	 * The queryTimeout limit is the number of seconds the driver will wait for
	 * a Statement to execute. If the limit is exceeded, a SQLException is
	 * thrown.
	 *
	 * @return the current query timeout limit in seconds; 0 = unlimited
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public int getQueryTimeout() throws SQLException {
		synchronized (checkClosed()) {
			return this.timeoutInMillis / 1000;
		}
	}

	/**
	 * Parses actual record count from 'info' message
	 *
	 * @param serverInfo
	 *            DOCUMENT ME!
	 *
	 * @return DOCUMENT ME!
	 */
	private int getRecordCountFromInfo(String serverInfo) {
		StringBuffer recordsBuf = new StringBuffer();
		int recordsCount = 0;
		int duplicatesCount = 0;

		char c = (char) 0;

		int length = serverInfo.length();
		int i = 0;

		for (; i < length; i++) {
			c = serverInfo.charAt(i);

			if (Character.isDigit(c)) {
				break;
			}
		}

		recordsBuf.append(c);
		i++;

		for (; i < length; i++) {
			c = serverInfo.charAt(i);

			if (!Character.isDigit(c)) {
				break;
			}

			recordsBuf.append(c);
		}

		recordsCount = Integer.parseInt(recordsBuf.toString());

		StringBuffer duplicatesBuf = new StringBuffer();

		for (; i < length; i++) {
			c = serverInfo.charAt(i);

			if (Character.isDigit(c)) {
				break;
			}
		}

		duplicatesBuf.append(c);
		i++;

		for (; i < length; i++) {
			c = serverInfo.charAt(i);

			if (!Character.isDigit(c)) {
				break;
			}

			duplicatesBuf.append(c);
		}

		duplicatesCount = Integer.parseInt(duplicatesBuf.toString());

		return recordsCount - duplicatesCount;
	}

	/**
	 * getResultSet returns the current result as a ResultSet. It should only be
	 * called once per result.
	 *
	 * @return the current result set; null if there are no more
	 *
	 * @exception SQLException
	 *                if a database access error occurs (why?)
	 */
	public java.sql.ResultSet getResultSet() throws SQLException {
		synchronized (checkClosed()) {
			return ((this.results != null) && this.results.reallyResult()) ? (java.sql.ResultSet) this.results
					: null;
		}
	}

	/**
	 * JDBC 2.0 Determine the result set concurrency.
	 *
	 * @return CONCUR_UPDATABLE or CONCUR_READONLY
	 *
	 * @throws SQLException
	 *             if an error occurs
	 */
	public int getResultSetConcurrency() throws SQLException {
		synchronized (checkClosed()) {
			return this.resultSetConcurrency;
		}
	}

	/**
	 * @see StatementImpl#getResultSetHoldability()
	 */
	public int getResultSetHoldability() throws SQLException {
		return java.sql.ResultSet.HOLD_CURSORS_OVER_COMMIT;
	}

	protected ResultSetInternalMethods getResultSetInternal() {
		try {
			synchronized (checkClosed()) {
				return this.results;
			}
		} catch (SQLException e) {
			return this.results; // you end up with the same thing as before, you'll get exception when actually trying to use it
		}
	}

	/**
	 * JDBC 2.0 Determine the result set type.
	 *
	 * @return the ResultSet type (SCROLL_SENSITIVE or SCROLL_INSENSITIVE)
	 *
	 * @throws SQLException
	 *             if an error occurs.
	 */
	public int getResultSetType() throws SQLException {
		synchronized (checkClosed()) {
			return this.resultSetType;
		}
	}

	/**
	 * getUpdateCount returns the current result as an update count, if the
	 * result is a ResultSet or there are no more results, -1 is returned. It
	 * should only be called once per result.
	 *
	 * @return the current result as an update count.
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public int getUpdateCount() throws SQLException {
		synchronized (checkClosed()) {
			if (this.results == null) {
				return -1;
			}
	
			if (this.results.reallyResult()) {
				return -1;
			}
	
			int truncatedUpdateCount = 0;
	
			if (this.results.getUpdateCount() > Integer.MAX_VALUE) {
				truncatedUpdateCount = Integer.MAX_VALUE;
			} else {
				truncatedUpdateCount = (int) this.results.getUpdateCount();
			}
	
			return truncatedUpdateCount;
		}
	}

	/**
	 * The first warning reported by calls on this Statement is returned. A
	 * Statement's execute methods clear its java.sql.SQLWarning chain.
	 * Subsequent Statement warnings will be chained to this
	 * java.sql.SQLWarning.
	 *
	 * <p>
	 * The Warning chain is automatically cleared each time a statement is
	 * (re)executed.
	 * </p>
	 *
	 * <p>
	 * <B>Note:</B> If you are processing a ResultSet then any warnings
	 * associated with ResultSet reads will be chained on the ResultSet object.
	 * </p>
	 *
	 * @return the first java.sql.SQLWarning or null
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public java.sql.SQLWarning getWarnings() throws SQLException {
		synchronized (checkClosed()) {

			if (this.clearWarningsCalled) {
				return null;
			}
			
			if (this.connection.versionMeetsMinimum(4, 1, 0)) {
				SQLWarning pendingWarningsFromServer = SQLError
						.convertShowWarningsToSQLWarnings(this.connection);
	
				if (this.warningChain != null) {
					this.warningChain.setNextWarning(pendingWarningsFromServer);
				} else {
					this.warningChain = pendingWarningsFromServer;
				}
	
				return this.warningChain;
			}
	
			return this.warningChain;
		}
	}

	/**
	 * Closes this statement, and frees resources.
	 *
	 * @param calledExplicitly
	 *            was this called from close()?
	 *
	 * @throws SQLException
	 *             if an error occurs
	 */
	protected void realClose(boolean calledExplicitly, boolean closeOpenResults)
			throws SQLException {
		MySQLConnection locallyScopedConn;
		
		try {
			locallyScopedConn = checkClosed();
		} catch (SQLException sqlEx) {
			return; // already closed
		}
		
		synchronized (locallyScopedConn) {
	
			if (this.useUsageAdvisor) {
				if (!calledExplicitly) {
					String message = Messages.getString("Statement.63") //$NON-NLS-1$
							+ Messages.getString("Statement.64"); //$NON-NLS-1$
	
					this.eventSink.consumeEvent(new ProfilerEvent(
							ProfilerEvent.TYPE_WARN,
							"", //$NON-NLS-1$
							this.currentCatalog, this.connectionId, this.getId(),
							-1, System.currentTimeMillis(), 0,
							Constants.MILLIS_I18N, null, this.pointOfOrigin,
							message));
				}
			}
	
			if (closeOpenResults) {
				closeOpenResults = !this.holdResultsOpenOverClose;
			}
			
			if (closeOpenResults) {
				if (this.results != null) {
					
					try {
						this.results.close();
					} catch (Exception ex) {
						;
					}
				}
				
				closeAllOpenResults();
			}
	
			if (this.connection != null) {
				if (this.maxRowsChanged) {
					this.connection.unsetMaxRows(this);
				}
	
				if (!this.connection.getDontTrackOpenResources()) {
					this.connection.unregisterStatement(this);
				}
			}
	
			this.isClosed = true;
	
			this.results = null;
			this.connection = null;
			this.warningChain = null;
			this.openResults = null;
			this.batchedGeneratedKeys = null;
			this.localInfileInputStream = null;
			this.pingTarget = null;
		}
	}

	/**
	 * setCursorName defines the SQL cursor name that will be used by subsequent
	 * execute methods. This name can then be used in SQL positioned
	 * update/delete statements to identify the current row in the ResultSet
	 * generated by this statement. If a database doesn't support positioned
	 * update/delete, this method is a no-op.
	 *
	 * <p>
	 * <b>Note:</b> This MySQL driver does not support cursors.
	 * </p>
	 *
	 * @param name
	 *            the new cursor name
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public void setCursorName(String name) throws SQLException {
		// No-op
	}

	/**
	 * If escape scanning is on (the default), the driver will do escape
	 * substitution before sending the SQL to the database.
	 *
	 * @param enable
	 *            true to enable; false to disable
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public void setEscapeProcessing(boolean enable)
			throws SQLException {
		synchronized (checkClosed()) {
			this.doEscapeProcessing = enable;
		}
	}

	/**
	 * JDBC 2.0 Give a hint as to the direction in which the rows in a result
	 * set will be processed. The hint applies only to result sets created using
	 * this Statement object. The default value is ResultSet.FETCH_FORWARD.
	 *
	 * @param direction
	 *            the initial direction for processing rows
	 *
	 * @exception SQLException
	 *                if a database-access error occurs or direction is not one
	 *                of ResultSet.FETCH_FORWARD, ResultSet.FETCH_REVERSE, or
	 *                ResultSet.FETCH_UNKNOWN
	 */
	public void setFetchDirection(int direction) throws SQLException {
		switch (direction) {
		case java.sql.ResultSet.FETCH_FORWARD:
		case java.sql.ResultSet.FETCH_REVERSE:
		case java.sql.ResultSet.FETCH_UNKNOWN:
			break;

		default:
			throw SQLError.createSQLException(
					Messages.getString("Statement.5"), //$NON-NLS-1$
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
		}
	}

	/**
	 * JDBC 2.0 Give the JDBC driver a hint as to the number of rows that should
	 * be fetched from the database when more rows are needed. The number of
	 * rows specified only affects result sets created using this statement. If
	 * the value specified is zero, then the hint is ignored. The default value
	 * is zero.
	 *
	 * @param rows
	 *            the number of rows to fetch
	 *
	 * @exception SQLException
	 *                if a database-access error occurs, or the condition 0
	 *                &lt;= rows &lt;= this.getMaxRows() is not satisfied.
	 */
	public void setFetchSize(int rows) throws SQLException {
		synchronized (checkClosed()) {
			if (((rows < 0) && (rows != Integer.MIN_VALUE))
					|| ((this.maxRows != 0) && (this.maxRows != -1) && (rows > this
							.getMaxRows()))) {
				throw SQLError.createSQLException(
						Messages.getString("Statement.7"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$ //$NON-NLS-2$
			}
	
			this.fetchSize = rows;
		}
	}

	public void setHoldResultsOpenOverClose(boolean holdResultsOpenOverClose) {
		try {
			synchronized (checkClosed()) {
				this.holdResultsOpenOverClose = holdResultsOpenOverClose;
			}
		} catch (SQLException e) {
			// FIXME: can't break interface at this point
		}
	}

	/**
	 * Sets the maxFieldSize
	 *
	 * @param max
	 *            the new max column size limit; zero means unlimited
	 *
	 * @exception SQLException
	 *                if size exceeds buffer size
	 */
	public void setMaxFieldSize(int max) throws SQLException {
		synchronized (checkClosed()) {
			if (max < 0) {
				throw SQLError.createSQLException(Messages
						.getString("Statement.11"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}
	
			int maxBuf = (this.connection != null) ? this.connection
					.getMaxAllowedPacket() : MysqlIO.getMaxBuf();
	
			if (max > maxBuf) {
				throw SQLError.createSQLException(Messages.getString(
						"Statement.13", //$NON-NLS-1$
						new Object[] { Long.valueOf(maxBuf) }), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}
	
			this.maxFieldSize = max;
		}
	}

	/**
	 * Set the maximum number of rows
	 *
	 * @param max
	 *            the new max rows limit; zero means unlimited
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 *
	 * @see getMaxRows
	 */
	public void setMaxRows(int max) throws SQLException {
		synchronized (checkClosed()) {
			if ((max > MysqlDefs.MAX_ROWS) || (max < 0)) {
				throw SQLError
						.createSQLException(
								Messages.getString("Statement.15") + max //$NON-NLS-1$
										+ " > " //$NON-NLS-1$ //$NON-NLS-2$
										+ MysqlDefs.MAX_ROWS + ".", SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$ //$NON-NLS-2$
			}
	
			if (max == 0) {
				max = -1;
			}
	
			this.maxRows = max;
			this.maxRowsChanged = true;
	
			if (this.maxRows == -1) {
				this.connection.unsetMaxRows(this);
				this.maxRowsChanged = false;
			} else {
				// Most people don't use setMaxRows()
				// so don't penalize them
				// with the extra query it takes
				// to do it efficiently unless we need
				// to.
				this.connection.maxRowsChanged(this);
			}
		}
	}

	/**
	 * Sets the queryTimeout limit
	 *
	 * @param seconds -
	 *            the new query timeout limit in seconds
	 *
	 * @exception SQLException
	 *                if a database access error occurs
	 */
	public void setQueryTimeout(int seconds) throws SQLException {
		synchronized (checkClosed()) {
			if (seconds < 0) {
				throw SQLError.createSQLException(Messages
						.getString("Statement.21"), //$NON-NLS-1$
						SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor()); //$NON-NLS-1$
			}
	
			this.timeoutInMillis = seconds * 1000;
		}
	}

	/**
	 * Sets the concurrency for result sets generated by this statement
	 *
	 * @param concurrencyFlag
	 *            DOCUMENT ME!
	 */
	void setResultSetConcurrency(int concurrencyFlag) {
		try {
			synchronized (checkClosed()) {
				this.resultSetConcurrency = concurrencyFlag;
			}
		} catch (SQLException e) {
			// FIXME: Can't break interface atm, we'll get the exception later when
			// you try and do something useful with a closed statement...
		}
	}

	/**
	 * Sets the result set type for result sets generated by this statement
	 *
	 * @param typeFlag
	 *            DOCUMENT ME!
	 */
	void setResultSetType(int typeFlag) {
		try {
			synchronized (checkClosed()) {
				this.resultSetType = typeFlag;
			}
		} catch (SQLException e) {
			// FIXME: Can't break interface atm, we'll get the exception later when
			// you try and do something useful with a closed statement...
		}
	}

	protected void getBatchedGeneratedKeys(java.sql.Statement batchedStatement) throws SQLException {
		synchronized (checkClosed()) {
			if (this.retrieveGeneratedKeys) {
				java.sql.ResultSet rs = null;
	
				try {
					rs = batchedStatement.getGeneratedKeys();
	
					while (rs.next()) {
						this.batchedGeneratedKeys
								.add(new ByteArrayRow(new byte[][] { rs.getBytes(1) }, getExceptionInterceptor()));
					}
				} finally {
					if (rs != null) {
						rs.close();
					}
				}
			}
		}
	}
	
	protected void getBatchedGeneratedKeys(int maxKeys) throws SQLException {
		synchronized (checkClosed()) {
			if (this.retrieveGeneratedKeys) {
				java.sql.ResultSet rs = null;
	
				try {
					if (maxKeys == 0)
						rs = getGeneratedKeysInternal();
					else
						rs = getGeneratedKeysInternal(maxKeys);
	
					while (rs.next()) {
						this.batchedGeneratedKeys
								.add(new ByteArrayRow(new byte[][] { rs.getBytes(1) }, getExceptionInterceptor()));
					}
				} finally {
					if (rs != null) {
						rs.close();
					}
				}
			}
		}
	}

	/**
	 * @return
	 */
	private boolean useServerFetch() throws SQLException {
		synchronized (checkClosed()) {
			return this.connection.isCursorFetchEnabled() && this.fetchSize > 0
					&& this.resultSetConcurrency == ResultSet.CONCUR_READ_ONLY
					&& this.resultSetType == ResultSet.TYPE_FORWARD_ONLY;
		}
	}

	public boolean isClosed() throws SQLException {
		try {
			synchronized (checkClosed()) {
				return this.isClosed;
			}
		} catch (SQLException sqlEx) {
			if (SQLError.SQL_STATE_CONNECTION_NOT_OPEN.equals(sqlEx.getSQLState())) {
				return true;
			}
			
			throw sqlEx;
		}
	}

	private boolean isPoolable = true;

	public boolean isPoolable() throws SQLException {
		return this.isPoolable;
	}

	public void setPoolable(boolean poolable) throws SQLException {
		this.isPoolable = poolable;
	}

	/**
     * Returns true if this either implements the interface argument or is directly or indirectly a wrapper
     * for an object that does. Returns false otherwise. If this implements the interface then return true,
     * else if this is a wrapper then return the result of recursively calling <code>isWrapperFor</code> on the wrapped
     * object. If this does not implement the interface and is not a wrapper, return false.
     * This method should be implemented as a low-cost operation compared to <code>unwrap</code> so that
     * callers can use this method to avoid expensive <code>unwrap</code> calls that may fail. If this method
     * returns true then calling <code>unwrap</code> with the same argument should succeed.
     *
     * @param interfaces a Class defining an interface.
     * @return true if this implements the interface or directly or indirectly wraps an object that does.
     * @throws java.sql.SQLException  if an error occurs while determining whether this is a wrapper
     * for an object with the given interface.
     * @since 1.6
     */
	public boolean isWrapperFor(Class<?> iface) throws SQLException {
		checkClosed();

		// This works for classes that aren't actually wrapping
		// anything
		return iface.isInstance(this);
	}

    /**
     * Returns an object that implements the given interface to allow access to non-standard methods,
     * or standard methods not exposed by the proxy.
     * The result may be either the object found to implement the interface or a proxy for that object.
     * If the receiver implements the interface then that is the object. If the receiver is a wrapper
     * and the wrapped object implements the interface then that is the object. Otherwise the object is
     *  the result of calling <code>unwrap</code> recursively on the wrapped object. If the receiver is not a
     * wrapper and does not implement the interface, then an <code>SQLException</code> is thrown.
     *
     * @param iface A Class defining an interface that the result must implement.
     * @return an object that implements the interface. May be a proxy for the actual implementing object.
     * @throws java.sql.SQLException If no object found that implements the interface
     * @since 1.6
     */
	public Object unwrap(Class<?> iface) throws java.sql.SQLException {
    	try {
    		// This works for classes that aren't actually wrapping
    		// anything
            return Util.cast(iface, this);
        } catch (ClassCastException cce) {
            throw SQLError.createSQLException("Unable to unwrap to " + iface.toString(),
            		SQLError.SQL_STATE_ILLEGAL_ARGUMENT, getExceptionInterceptor());
        }
    }

	protected int findStartOfStatement(String sql) {
		int statementStartPos = 0;

		if (StringUtils.startsWithIgnoreCaseAndWs(sql, "/*")) {
			statementStartPos = sql.indexOf("*/");

			if (statementStartPos == -1) {
				statementStartPos = 0;
			} else {
				statementStartPos += 2;
			}
		} else if (StringUtils.startsWithIgnoreCaseAndWs(sql, "--")
			|| StringUtils.startsWithIgnoreCaseAndWs(sql, "#")) {
			statementStartPos = sql.indexOf('\n');

			if (statementStartPos == -1) {
				statementStartPos = sql.indexOf('\r');

				if (statementStartPos == -1) {
					statementStartPos = 0;
				}
			}
		}

		return statementStartPos;
	}

	private InputStream localInfileInputStream;

	protected final boolean version5013OrNewer;

    public InputStream getLocalInfileInputStream() {
        return this.localInfileInputStream;
    }

    public void setLocalInfileInputStream(InputStream stream) {
        this.localInfileInputStream = stream;
    }
    
    public void setPingTarget(PingTarget pingTarget) {
		this.pingTarget = pingTarget;
	}
    
    public ExceptionInterceptor getExceptionInterceptor() {
    	return this.exceptionInterceptor;
    }
	
	protected boolean containsOnDuplicateKeyInString(String sql) {
		return getOnDuplicateKeyLocation(sql) != -1;
	}
	
	protected int getOnDuplicateKeyLocation(String sql) {
		return StringUtils.indexOfIgnoreCaseRespectMarker(0, 
				sql, "ON DUPLICATE KEY UPDATE ", "\"'`", "\"'`", !this.connection.isNoBackslashEscapesSet());
	}
	
	private boolean closeOnCompletion;
	
	public void closeOnCompletion() throws SQLException {
		synchronized (checkClosed()) {
			closeOnCompletion = true;
		}
	}
	
	public boolean isCloseOnCompletion() throws SQLException {
		synchronized (checkClosed()) {
			return closeOnCompletion;
		}
	}
}