/*
 * Copyright 2002-2004 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.core;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.JdkVersion;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.IncorrectResultSizeDataAccessException;
import org.springframework.dao.InvalidDataAccessApiUsageException;
import org.springframework.dao.TypeMismatchDataAccessException;
import org.springframework.jdbc.SQLWarningException;
import org.springframework.jdbc.datasource.DataSourceUtils;
import org.springframework.jdbc.support.JdbcAccessor;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.jdbc.support.nativejdbc.NativeJdbcExtractor;

/**
 * <b>This is the central class in the JDBC core package.</b>
 * It simplifies the use of JDBC and helps to avoid common errors.
 * It executes core JDBC workflow, leaving application code to provide SQL
 * and extract results. This class executes SQL queries or updates, initiating
 * iteration over ResultSets and catching JDBC exceptions and translating
 * them to the generic, more informative exception hierarchy defined in the
 * org.springframework.dao package.
 *
 * <p>Code using this class need only implement callback interfaces, giving
 * them a clearly defined contract. The PreparedStatementCreator callback
 * interface creates a prepared statement given a Connection provided by this
 * class, providing SQL and any necessary parameters. The RowCallbackHandler
 * interface extracts values from each row of a ResultSet.
 *
 * <p>Can be used within a service implementation via direct instantiation
 * with a DataSource reference, or get prepared in an application context
 * and given to services as bean reference. Note: The DataSource should
 * always be configured as a bean in the application context, in the first case
 * given to the service directly, in the second case to the prepared template.
 *
 * <p>The motivation and design of this class is discussed
 * in detail in
 * <a href="http://www.amazon.com/exec/obidos/tg/detail/-/0764543857/">Expert One-On-One J2EE Design and Development</a>
 * by Rod Johnson (Wrox, 2002).
 *
 * <p>Because this class is parameterizable by the callback interfaces and
 * the SQLExceptionTranslator interface, it isn't necessary to subclass it.
 * All SQL issued by this class is logged.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Yann Caroff
 * @author Thomas Risberg
 * @author Isabelle Muszynski
 * @version $Id: JdbcTemplate.java,v 1.45 2004/06/02 17:09:47 jhoeller Exp $
 * @since May 3, 2001
 * @see ResultSetExtractor
 * @see RowCallbackHandler
 * @see RowMapper
 * @see org.springframework.dao
 * @see org.springframework.jdbc.datasource
 * @see org.springframework.jdbc.object
 */
public class JdbcTemplate extends JdbcAccessor implements JdbcOperations, InitializingBean {

	protected final Log logger = LogFactory.getLog(getClass());

	/** Custom NativeJdbcExtractor */
	private NativeJdbcExtractor nativeJdbcExtractor;

	/** If this variable is false, we will throw exceptions on SQL warnings */
	private boolean ignoreWarnings = true;


	/**
	 * Construct a new JdbcTemplate for bean usage.
	 * Note: The DataSource has to be set before using the instance.
	 * This constructor can be used to prepare a JdbcTemplate via a BeanFactory,
	 * typically setting the DataSource via setDataSource.
	 * @see #setDataSource
	 */
	public JdbcTemplate() {
	}

	/**
	 * Construct a new JdbcTemplate, given a DataSource to obtain connections from.
	 * Note: This will trigger eager initialization of the exception translator.
	 * @param dataSource JDBC DataSource to obtain connections from
	 */
	public JdbcTemplate(DataSource dataSource) {
		setDataSource(dataSource);
		afterPropertiesSet();
	}

	/**
	 * Set a NativeJdbcExtractor to extract native JDBC objects from wrapped handles.
	 * Useful if native Statement and/or ResultSet handles are expected for casting
	 * to database-specific implementation classes, but a connection pool that wraps
	 * JDBC objects is used (note: <i>any</i> pool will return wrapped Connections).
	 */
	public void setNativeJdbcExtractor(NativeJdbcExtractor extractor) {
		this.nativeJdbcExtractor = extractor;
	}

	/**
	 * Return the current NativeJdbcExtractor implementation.
	 */
	public NativeJdbcExtractor getNativeJdbcExtractor() {
		return this.nativeJdbcExtractor;
	}

	/**
	 * Set whether or not we want to ignore SQLWarnings.
	 * Default is true.
	 */
	public void setIgnoreWarnings(boolean ignoreWarnings) {
		this.ignoreWarnings = ignoreWarnings;
	}

	/**
	 * Return whether or not we ignore SQLWarnings.
	 * Default is true.
	 */
	public boolean getIgnoreWarnings() {
		return ignoreWarnings;
	}


	//-------------------------------------------------------------------------
	// Methods dealing with static SQL (java.sql.Statement)
	//-------------------------------------------------------------------------

	public Object execute(final StatementCallback action) {
		Connection con = DataSourceUtils.getConnection(getDataSource());
		Statement stmt = null;
		try {
			Connection conToUse = con;
			if (this.nativeJdbcExtractor != null &&
					this.nativeJdbcExtractor.isNativeConnectionNecessaryForNativeStatements()) {
				conToUse = this.nativeJdbcExtractor.getNativeConnection(con);
			}
			stmt = conToUse.createStatement();
			DataSourceUtils.applyTransactionTimeout(stmt, getDataSource());
			Statement stmtToUse = stmt;
			if (this.nativeJdbcExtractor != null) {
				stmtToUse = this.nativeJdbcExtractor.getNativeStatement(stmt);
			}
			Object result = action.doInStatement(stmtToUse);
			SQLWarning warning = stmt.getWarnings();
			throwExceptionOnWarningIfNotIgnoringWarnings(warning);
			return result;
		}
		catch (SQLException ex) {
			throw getExceptionTranslator().translate("executing StatementCallback", null, ex);
		}
		finally {
			JdbcUtils.closeStatement(stmt);
			DataSourceUtils.closeConnectionIfNecessary(con, getDataSource());
		}
	}

	public void execute(final String sql) throws DataAccessException {
		if (logger.isDebugEnabled()) {
			logger.debug("Executing SQL statement [" + sql + "]");
		}
		execute(new StatementCallback() {
			public Object doInStatement(Statement stmt) throws SQLException {
				stmt.execute(sql);
				return null;
			}
		});
	}

	public Object query(final String sql, final ResultSetExtractor rse) throws DataAccessException {
		if (sql == null) {
			throw new InvalidDataAccessApiUsageException("SQL must not be null");
		}
		if (sql.indexOf("?") != -1) {
			throw new InvalidDataAccessApiUsageException(
					"Cannot execute [" + sql + "] as a static query: it contains bind variables");
		}
		if (logger.isDebugEnabled()) {
			logger.debug("Executing SQL query [" + sql + "]");
		}
		return execute(new StatementCallback() {
			public Object doInStatement(Statement stmt) throws SQLException {
				ResultSet rs = null;
				try {
					rs = stmt.executeQuery(sql);
					ResultSet rsToUse = rs;
					if (nativeJdbcExtractor != null) {
						rsToUse = nativeJdbcExtractor.getNativeResultSet(rs);
					}
					return rse.extractData(rsToUse);
				}
				finally {
					JdbcUtils.closeResultSet(rs);
				}
			}
		});
	}

	public List query(String sql, RowCallbackHandler rch) throws DataAccessException {
		return (List) query(sql, new RowCallbackHandlerResultSetExtractor(rch));
	}

	public List queryForList(String sql) throws DataAccessException {
		return (List) query(sql, new ListResultSetExtractor());
	}

	public Object queryForObject(String sql, Class requiredType) throws DataAccessException {
		return query(sql, new ObjectResultSetExtractor(requiredType));
	}

	public long queryForLong(String sql) throws DataAccessException {
		Number number = (Number) queryForObject(sql, Number.class);
		return (number != null ? number.longValue() : 0);
	}

	public int queryForInt(String sql) throws DataAccessException {
		Number number = (Number) queryForObject(sql, Number.class);
		return (number != null ? number.intValue() : 0);
	}

	public int update(final String sql) throws DataAccessException {
		if (logger.isDebugEnabled()) {
			logger.debug("Executing SQL update [" + sql + "]");
		}
		Integer result = (Integer) execute(new StatementCallback() {
			public Object doInStatement(Statement stmt) throws SQLException {
				int rows = stmt.executeUpdate(sql);
				if (logger.isDebugEnabled()) {
					logger.debug("SQL update affected " + rows + " rows");
				}
				return new Integer(rows);
			}
		});
		return result.intValue();
	}


	//-------------------------------------------------------------------------
	// Methods dealing with prepared statements
	//-------------------------------------------------------------------------

	public Object execute(PreparedStatementCreator psc, PreparedStatementCallback action) {
		Connection con = DataSourceUtils.getConnection(getDataSource());
		PreparedStatement ps = null;
		try {
			Connection conToUse = con;
			if (this.nativeJdbcExtractor != null &&
					this.nativeJdbcExtractor.isNativeConnectionNecessaryForNativePreparedStatements()) {
				conToUse = this.nativeJdbcExtractor.getNativeConnection(con);
			}
			ps = psc.createPreparedStatement(conToUse);
			DataSourceUtils.applyTransactionTimeout(ps, getDataSource());
			PreparedStatement psToUse = ps;
			if (this.nativeJdbcExtractor != null) {
				psToUse = this.nativeJdbcExtractor.getNativePreparedStatement(ps);
			}
			Object result = action.doInPreparedStatement(psToUse);
			SQLWarning warning = ps.getWarnings();
			throwExceptionOnWarningIfNotIgnoringWarnings(warning);
			return result;
		}
		catch (SQLException ex) {
			throw getExceptionTranslator().translate("executing PreparedStatementCallback [" + psc + "]",
																							 getSql(psc), ex);
		}
		finally {
			JdbcUtils.closeStatement(ps);
			DataSourceUtils.closeConnectionIfNecessary(con, getDataSource());
		}
	}

	public Object execute(final String sql, PreparedStatementCallback action) {
		return execute(new SimplePreparedStatementCreator(sql), action);
	}

	/**
	 * Query using a prepared statement, allowing for a PreparedStatementCreator
	 * and a PreparedStatementSetter. Most other query methods use this method,
	 * but application code will always work with either a creator or a setter.
	 * @param psc Callback handler that can create a PreparedStatement given a
	 * Connection
	 * @param pss object that knows how to set values on the prepared statement.
	 * If this is null, the SQL will be assumed to contain no bind parameters.
	 * @param rse object that will extract results.
	 * @return an arbitrary result object, as returned by the ResultSetExtractor
	 * @throws DataAccessException if there is any problem
	 */
	protected Object query(PreparedStatementCreator psc, final PreparedStatementSetter pss,
												 final ResultSetExtractor rse) throws DataAccessException {
		if (logger.isDebugEnabled()) {
			String sql = getSql(psc);
			logger.debug("Executing SQL query" + (sql != null ? " [" + sql  + "]" : ""));
		}
		return execute(psc, new PreparedStatementCallback() {
			public Object doInPreparedStatement(PreparedStatement ps) throws SQLException {
				if (pss != null) {
					pss.setValues(ps);
				}
				ResultSet rs = null;
				try {
					rs = ps.executeQuery();
					ResultSet rsToUse = rs;
					if (nativeJdbcExtractor != null) {
						rsToUse = nativeJdbcExtractor.getNativeResultSet(rs);
					}
					return rse.extractData(rsToUse);
				}
				finally {
					JdbcUtils.closeResultSet(rs);
				}
			}
		});
	}

	public Object query(PreparedStatementCreator psc, ResultSetExtractor rse) {
		return query(psc, null, rse);
	}

	public Object query(final String sql, final PreparedStatementSetter pss, final ResultSetExtractor rse)
			throws DataAccessException {
		if (sql == null) {
			throw new InvalidDataAccessApiUsageException("SQL may not be null");
		}
		return query(new SimplePreparedStatementCreator(sql), pss, rse);
	}

	public Object query(String sql, Object[] args, int[] argTypes, ResultSetExtractor rse) {
		return query(sql, new ArgTypePreparedStatementSetter(args, argTypes), rse);
	}

	public Object query(String sql, Object[] args, ResultSetExtractor rse) {
		return query(sql, new ArgPreparedStatementSetter(args), rse);
	}

	public List query(PreparedStatementCreator psc, RowCallbackHandler rch)
			throws DataAccessException {
		return (List) query(psc, new RowCallbackHandlerResultSetExtractor(rch));
	}

	public List query(String sql, final PreparedStatementSetter pss, final RowCallbackHandler rch)
			throws DataAccessException {
		return (List) query(sql, pss, new RowCallbackHandlerResultSetExtractor(rch));
	}

	public List query(String sql, final Object[] args, final int[] argTypes, RowCallbackHandler rch)
			throws DataAccessException {
		return query(sql, new ArgTypePreparedStatementSetter(args, argTypes), rch);
	}

	public List query(String sql, final Object[] args, RowCallbackHandler rch)
			throws DataAccessException {
		return query(sql, new ArgPreparedStatementSetter(args), rch);
	}

	public List queryForList(String sql, final Object[] args) throws DataAccessException {
		return (List) query(sql,
				new ArgPreparedStatementSetter(args),
				new ListResultSetExtractor());
	}

	public Object queryForObject(String sql, Object[] args, Class requiredType)
			throws DataAccessException {
		return query(sql,
				new ArgPreparedStatementSetter(args),
				new ObjectResultSetExtractor(requiredType));
	}

	public long queryForLong(String sql, final Object[] args) throws DataAccessException {
		Number number = (Number) queryForObject(sql, args, Number.class);
		return (number != null ? number.longValue() : 0);
	}

	public int queryForInt(String sql, final Object[] args) throws DataAccessException {
		Number number = (Number) queryForObject(sql, args, Number.class);
		return (number != null ? number.intValue() : 0);
	}

	protected int update(PreparedStatementCreator psc, final PreparedStatementSetter pss) throws DataAccessException {
		if (logger.isDebugEnabled()) {
			String sql = getSql(psc);
			logger.debug("Executing SQL update" + (sql != null ? " [" + sql  + "]" : ""));
		}
		Integer result = (Integer) execute(psc, new PreparedStatementCallback() {
			public Object doInPreparedStatement(PreparedStatement ps) throws SQLException {
				if (pss != null) {
					pss.setValues(ps);
				}
				int rows = ps.executeUpdate();
				if (logger.isDebugEnabled()) {
					logger.debug("SQL update affected " + rows + " rows");
				}
				return new Integer(rows);
			}
		});
		return result.intValue();
	}

	public int update(PreparedStatementCreator psc) throws DataAccessException {
		return update(psc, null);
	}

	public int update(String sql, final PreparedStatementSetter pss) throws DataAccessException {
		return update(new SimplePreparedStatementCreator(sql), pss);
	}

	public int update(String sql, final Object[] args, final int[] argTypes) throws DataAccessException {
		return update(sql, new ArgTypePreparedStatementSetter(args, argTypes));
	}

	public int update(String sql, final Object[] args) throws DataAccessException {
		return update(sql, new ArgPreparedStatementSetter(args));
	}

	public int[] batchUpdate(String sql, final BatchPreparedStatementSetter pss) throws DataAccessException {
		if (logger.isDebugEnabled()) {
			logger.debug("Executing SQL batch update [" + sql + "]");
		}
		return (int[]) execute(sql, new PreparedStatementCallback() {
			public Object doInPreparedStatement(PreparedStatement ps) throws SQLException {
				int batchSize = pss.getBatchSize();
				DatabaseMetaData dbmd = ps.getConnection().getMetaData();
				if (dbmd != null && dbmd.supportsBatchUpdates()) {
					for (int i = 0; i < batchSize; i++) {
						pss.setValues(ps, i);
						ps.addBatch();
					}
					return ps.executeBatch();
				}
				else {
					int[] rowsAffected = new int[batchSize];
					for (int i = 0; i < batchSize; i++) {
						pss.setValues(ps, i);
						rowsAffected[i] = ps.executeUpdate();
					}
					return rowsAffected;
				}
			}
		});
	}


	//-------------------------------------------------------------------------
	// Methods dealing with callable statements
	//-------------------------------------------------------------------------

	public Object execute(CallableStatementCreator csc, CallableStatementCallback action) {
		if (logger.isDebugEnabled()) {
			String sql = getSql(csc);
			logger.debug("Calling stored procedure" + (sql != null ? " [" + sql  + "]" : ""));
		}
		Connection con = DataSourceUtils.getConnection(getDataSource());
		CallableStatement cs = null;
		try {
			Connection conToUse = con;
			if (this.nativeJdbcExtractor != null &&
					this.nativeJdbcExtractor.isNativeConnectionNecessaryForNativeCallableStatements()) {
				conToUse = this.nativeJdbcExtractor.getNativeConnection(con);
			}
			cs = csc.createCallableStatement(conToUse);
			DataSourceUtils.applyTransactionTimeout(cs, getDataSource());
			CallableStatement csToUse = cs;
			if (nativeJdbcExtractor != null) {
				csToUse = nativeJdbcExtractor.getNativeCallableStatement(cs);
			}
			Object result = action.doInCallableStatement(csToUse);
			SQLWarning warning = cs.getWarnings();
			throwExceptionOnWarningIfNotIgnoringWarnings(warning);
			return result;
		}
		catch (SQLException ex) {
			throw getExceptionTranslator().translate("executing CallableStatementCallback [" + csc + "]",
																							 getSql(csc), ex);
		}
		finally {
			JdbcUtils.closeStatement(cs);
			DataSourceUtils.closeConnectionIfNecessary(con, getDataSource());
		}
	}

	public Object execute(final String callString, CallableStatementCallback action) {
		return execute(new SimpleCallableStatementCreator(callString), action);
	}

	public Map call(CallableStatementCreator csc, final List declaredParameters) throws DataAccessException {
		return (Map) execute(csc, new CallableStatementCallback() {
			public Object doInCallableStatement(CallableStatement cs) throws SQLException {
				boolean retVal = cs.execute();
				if (logger.isDebugEnabled()) {
					logger.debug("CallableStatement.execute returned [" + retVal + "]");
				}
				Map returnedResults = new HashMap();
				if (retVal) {
					returnedResults.putAll(extractReturnedResultSets(cs, declaredParameters));
				}
				returnedResults.putAll(extractOutputParameters(cs, declaredParameters));
				return returnedResults;
			}
		});
	}

	/**
	 * Extract returned ResultSets from the completed stored procedure.
	 * @param cs JDBC wrapper for the stored procedure
	 * @param parameters Parameter list for the stored procedure
	 * @return Map that contains returned results
	 */
	protected Map extractReturnedResultSets(CallableStatement cs, List parameters) throws SQLException {
		Map returnedResults = new HashMap();
		int rsIndex = 0;
		do {
			Object param = null;
			if (parameters != null && parameters.size() > rsIndex) {
				param = parameters.get(rsIndex);
			}
			if (param instanceof SqlReturnResultSet) {
				SqlReturnResultSet rsParam = (SqlReturnResultSet) param;
				returnedResults.putAll(processResultSet(cs.getResultSet(), rsParam));
			}
			else {
				logger.warn("ResultSet returned from stored procedure but a corresponding " +
										"SqlReturnResultSet parameter was not declared");
			}
			rsIndex++;
		}
		while (cs.getMoreResults());
		return returnedResults;
	}

	/**
	 * Extract output parameters from the completed stored procedure.
	 * @param cs JDBC wrapper for the stored procedure
	 * @param parameters parameter list for the stored procedure
	 * @return parameters to the stored procedure
	 * @return Map that contains returned results
	 */
	protected Map extractOutputParameters(CallableStatement cs, List parameters) throws SQLException {
		Map returnedResults = new HashMap();
		int sqlColIndex = 1;
		for (int i = 0; i < parameters.size(); i++) {
			Object param = parameters.get(i);
			if (param instanceof SqlOutParameter) {
				SqlOutParameter outParam = (SqlOutParameter) param;
				Object out = cs.getObject(sqlColIndex);
				if (out instanceof ResultSet) {
					if (outParam.isResultSetSupported()) {
						returnedResults.putAll(processResultSet((ResultSet) out, outParam));
					}
					else {
						logger.warn("ResultSet returned from stored procedure but a corresponding " +
												"SqlOutParameter with a RowCallbackHandler was not declared");
						returnedResults.put(outParam.getName(), "ResultSet was returned but not processed.");
					}
				}
				else {
					returnedResults.put(outParam.getName(), out);
				}
			}
			if (!(param instanceof SqlReturnResultSet)) {
				sqlColIndex++;
			}
		}
		return returnedResults;
	}

	/**
	 * Process the given ResultSet from a stored procedure.
	 * @param rs the ResultSet to process
	 * @param param the corresponding stored procedure parameter
	 * @return Map that contains returned results
	 */
	protected Map processResultSet(ResultSet rs, ResultSetSupportingSqlParameter param) throws SQLException {
		Map returnedResults = new HashMap();
		try {
			ResultSet rsToUse = rs;
			if (this.nativeJdbcExtractor != null) {
				rsToUse = this.nativeJdbcExtractor.getNativeResultSet(rs);
			}
			if (param.isRowCallbackHandlerSupported()) {
				// It's a RowCallbackHandler or RowMapper.
				// We'll get a RowCallbackHandler to use in both cases.
				RowCallbackHandler rch = param.getRowCallbackHandler();
				(new RowCallbackHandlerResultSetExtractor(rch)).extractData(rsToUse);
				if (rch instanceof ResultReader) {
					returnedResults.put(param.getName(), ((ResultReader) rch).getResults());
				}
				else {
					returnedResults.put(param.getName(), "ResultSet returned from stored procedure was processed.");
				}
			}
			else {
				// It's a ResultSetExtractor - simply apply it.
				Object result = param.getResultSetExtractor().extractData(rsToUse);
				returnedResults.put(param.getName(), result);
			}
		}
		finally {
			JdbcUtils.closeResultSet(rs);
		}
		return returnedResults;
	}


	/**
	 * Throw an SQLWarningException if we're not ignoring warnings.
	 * @param warning warning from current statement. May be null,
	 * in which case this method does nothing.
	 */
	private void throwExceptionOnWarningIfNotIgnoringWarnings(SQLWarning warning) throws SQLWarningException {
		if (warning != null) {
			if (this.ignoreWarnings) {
				logger.warn("SQLWarning ignored: " + warning);
			}
			else {
				throw new SQLWarningException("Warning not ignored", warning);
			}
		}
	}

	/**
	 * Determine SQL from potential provider object.
	 * @param sqlProvider object that's potentially a SqlProvider
	 * @return the SQL string, or null
	 * @see SqlProvider
	 */
	private String getSql(Object sqlProvider) {
		if (sqlProvider instanceof SqlProvider) {
			return ((SqlProvider) sqlProvider).getSql();
		}
		else {
			return null;
		}
	}


	/**
	 * Simple adapter for PreparedStatementCreator, allowing to use a plain SQL statement.
	 */
	private static class SimplePreparedStatementCreator
			implements PreparedStatementCreator, SqlProvider {

		private final String sql;

		public SimplePreparedStatementCreator(String sql) {
			this.sql = sql;
		}

		public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
			return con.prepareStatement(this.sql);
		}

		public String getSql() {
			return sql;
		}
	}


	/**
	 * Simple adapter for CallableStatementCreator, allowing to use a plain SQL statement.
	 */
	private static class SimpleCallableStatementCreator
			implements CallableStatementCreator, SqlProvider {

		private final String callString;

		public SimpleCallableStatementCreator(String callString) {
			this.callString = callString;
		}

		public CallableStatement createCallableStatement(Connection con) throws SQLException {
			return con.prepareCall(this.callString);
		}

		public String getSql() {
			return callString;
		}

	}


	/**
	 * Simple adapter for PreparedStatementSetter that applies
	 * a given array of arguments.
	 */
	private static class ArgPreparedStatementSetter implements PreparedStatementSetter {

		private final Object[] args;

		public ArgPreparedStatementSetter(Object[] args) {
			this.args = args;
		}

		public void setValues(PreparedStatement ps) throws SQLException {
			if (this.args != null) {
				for (int i = 0; i < this.args.length; i++) {
					ps.setObject(i + 1, this.args[i]);
				}
			}
		}
	}


	/**
	 * Simple adapter for PreparedStatementSetter that applies
	 * given arrays of arguments and JDBC argument types.
	 */
	private static class ArgTypePreparedStatementSetter implements PreparedStatementSetter {

		private final Object[] args;

		private final int[] argTypes;

		public ArgTypePreparedStatementSetter(Object[] args, int[] argTypes) {
			if ((args != null && argTypes == null) || (args == null && argTypes != null) ||
					(args != null && args.length != argTypes.length)) {
				throw new InvalidDataAccessApiUsageException("args and argTypes parameters must match");
			}
			this.args = args;
			this.argTypes = argTypes;
		}

		public void setValues(PreparedStatement ps) throws SQLException {
			if (this.args != null) {
				for (int i = 0; i < this.args.length; i++) {
					ps.setObject(i + 1, this.args[i], this.argTypes[i]);
				}
			}
		}
	}


	/**
	 * Adapter to enable use of a RowCallbackHandler inside a ResultSetExtractor.
	 * <p>Uses a regular ResultSet, so we have to be careful when using it:
	 * We don't use it for navigating since this could lead to unpredictable consequences.
	 */
	private static class RowCallbackHandlerResultSetExtractor implements ResultSetExtractor {

		private final RowCallbackHandler rch;

		public RowCallbackHandlerResultSetExtractor(RowCallbackHandler rch) {
			this.rch = rch;
		}

		public Object extractData(ResultSet rs) throws SQLException {
			while (rs.next()) {
				this.rch.processRow(rs);
			}
			if (this.rch instanceof ResultReader) {
				return ((ResultReader) this.rch).getResults();
			}
			else {
				return null;
			}
		}
	}


	/**
	 * ResultSetExtractor implementation that returns an ArrayList of HashMaps.
	 */
	private static class ListResultSetExtractor implements ResultSetExtractor {

		public Object extractData(ResultSet rs) throws SQLException {
			ResultSetMetaData rsmd = rs.getMetaData();
			int numberOfColumns = rsmd.getColumnCount();
			List listOfRows = new ArrayList();
			while (rs.next()) {
				Map mapOfColValues = null;
				// A LinkedHashMap will preserve column order, but is not available pre-1.4.
				if (JdkVersion.getMajorJavaVersion() >= JdkVersion.JAVA_14) {
					mapOfColValues = LinkedHashMapCreator.createLinkedHashMap(numberOfColumns);
				}
				else {
					mapOfColValues = new HashMap(numberOfColumns);
				}
				for (int i = 1; i <= numberOfColumns; i++) {
					mapOfColValues.put(rsmd.getColumnName(i), rs.getObject(i));
				}
				listOfRows.add(mapOfColValues);
			}
			return listOfRows;
		}
	}


	/**
	 * ResultSetExtractor implementation that returns single result object.
	 */
	private static class ObjectResultSetExtractor implements ResultSetExtractor {

		private final Class requiredType;

		public ObjectResultSetExtractor(Class requiredType) {
			this.requiredType = requiredType;
		}

		public Object extractData(ResultSet rs) throws SQLException {
			ResultSetMetaData rsmd = rs.getMetaData();
			int nrOfColumns = rsmd.getColumnCount();
			if (nrOfColumns != 1) {
				throw new IncorrectResultSizeDataAccessException("Expected single column but found " + nrOfColumns,
																												 1, nrOfColumns);
			}
			if (!rs.next()) {
				throw new IncorrectResultSizeDataAccessException("Expected single row but found none", 1, 0);
			}
			Object result = rs.getObject(1);
			if (rs.next()) {
				throw new IncorrectResultSizeDataAccessException("Expected single row but found more than one", 1, -1);
			}
			if (result != null && this.requiredType != null && !this.requiredType.isInstance(result)) {
				throw new TypeMismatchDataAccessException("Result object (db-type=\"" + rsmd.getColumnTypeName(1) +
																									"\" value=\"" + result + "\") is of type [" +
																									rsmd.getColumnClassName(1) + "] and not of required type [" +
																									this.requiredType.getName() + "]");
			}
			return result;
		}
	}


	/**
	 * Actual creation of a java.util.LinkedHashMap.
	 * In separate inner class to avoid runtime dependency on JDK 1.4.
	 */
	private static abstract class LinkedHashMapCreator {

		private static Map createLinkedHashMap(int capacity) {
			return new LinkedHashMap(capacity);
		}
	}

}