jdbcpreparedstatement.java

hsql是很有名的嵌入式数据库

/* Copyright (c) 2001-2005, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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package org.hsqldb.jdbc;

import java.io.IOException;
import java.io.Serializable;
import java.math.BigDecimal;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.Calendar;

//#ifdef JAVA2
import java.sql.Array;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.Ref;

//#endif JAVA2
//#ifdef JDBC3
import java.sql.ParameterMetaData;

//#endif JDBC3
import org.hsqldb.Column;
import org.hsqldb.HsqlDateTime;
import org.hsqldb.HsqlException;
import org.hsqldb.Result;
import org.hsqldb.ResultConstants;
import org.hsqldb.Trace;
import org.hsqldb.Types;
import org.hsqldb.lib.ArrayUtil;
import org.hsqldb.lib.HsqlByteArrayOutputStream;
import org.hsqldb.lib.Iterator;
import org.hsqldb.lib.StringConverter;
import org.hsqldb.types.Binary;
import org.hsqldb.types.JavaObject;

// fredt@users 20020320 - patch 1.7.0 - JDBC 2 support and error trapping
// JDBC 2 methods can now be called from jdk 1.1.x - see javadoc comments
// boucherb@users 20020509 - added "throws SQLException" to all methods where
// it was missing here but specified in the java.sql.PreparedStatement and
// java.sqlCallableStatement interfaces, updated generic documentation to
// JDK 1.4, and added JDBC3 methods and docs
// boucherb@users and fredt@users 20020409/20020505 extensive review and update
// of docs and behaviour to comply with previous and latest java.sql specification
// fredt@users 20030620 - patch 1.7.2 - rewritten to support real prepared statements
// boucherb@users 20030801 - patch 1.7.2 - support for batch execution
// boucherb@users 20030801 - patch 1.7.2 - support for getMetaData and getParameterMetadata
// boucherb@users 20030801 - patch 1.7.2 - updated some setXXX methods
// boucherb@users 200403/4xx - doc 1.7.2 - javadoc updates toward 1.7.2 final
// boucherb@users 200403/4xx - patch 1.7.2 - eliminate eager buffer allocation from setXXXStream/Blob/Clob

/**
 * <!-- start generic documentation -->
 *
 * An object that represents a precompiled SQL statement. <p>
 *
 * An SQL statement is precompiled and stored in a
 * <code>PreparedStatement</code> object. This object can then be used to
 * efficiently execute this statement multiple times.
 *
 * <P><B>Note:</B> The setter methods (<code>setShort</code>,
 * <code>setString</code>, and so on) for setting IN parameter values
 * must specify types that are compatible with the defined SQL type of
 * the input parameter. For instance, if the IN parameter has SQL type
 * <code>INTEGER</code>, then the method <code>setInt</code> should be
 * used. <p>
 *
 * If arbitrary parameter type conversions are required, the method
 * <code>setObject</code> should be used with a target SQL type.
 * <P>
 * In the following example of setting a parameter, <code>con</code>
 * represents an active connection:
 * <PRE>
 * PreparedStatement pstmt = con.prepareStatement("UPDATE EMPLOYEES
 *                               SET SALARY = ? WHERE ID = ?");
 * pstmt.setBigDecimal(1, 153833.00)
 * pstmt.setInt(2, 110592)
 * </PRE> <p>
 * <!-- end generic documentation -->
 * <!-- start Release-specific documentation -->
 * <div class="ReleaseSpecificDocumentation">
 * <h3>HSQLDB-Specific Information:</h3> <p>
 *
 * Starting with HSQLDB 1.7.2, jdbcPreparedStatement objects are backed by
 * a true compiled parameteric representation. Hence, there are now significant
 * performance gains to be had by using a jdbcPreparedStatement object in
 * preference to a jdbcStatement object, if a short-running SQL statement is
 * to be executed more than a small number of times. <p>
 *
 * Please note, however, that 1.7.2 does not yet provide a sophisticated
 * internal statement pooling facility.  For this reason, the observation
 * above is guaranteed to apply only under certain use patterns. <p>
 *
 * Specifically, when it can be otherwise avoided, it is to be considered poor
 * practice to fully prepare (construct), parameterize, execute, fetch and
 * close a jdbcPreparedStatement object for each execution cycle. Indeed, under
 * HSQLDB 1.7.2, this practice is likely to be noticably <em>less</em>
 * performant for short-running statements than the equivalent process using
 * jdbcStatement objects, albeit far more convenient, less error prone and
 * certainly much less resource-intensive, especially when large binary and
 * character values are involved, due to the optimized parameterization
 * facility. <p>
 *
 * Instead, when developing an application that is not totally oriented toward
 * the execution of ad hoc SQL, it is recommended to expend some effort toward
 * identifing the SQL statements that are good candidates for regular reuse and
 * adapting the structure of the application accordingly. Often, this is done
 * by recording the text of candidate SQL statements in an application resource
 * object (which has the nice side-benefit of isolating and hiding differences
 * in SQL dialects across different drivers) and caching for possible reuse the
 * PreparedStatement objects derived from the recorded text. <p>
 *
 * <b>Multi thread use:</b> <p>
 *
 * A PreparedStatement object is stateful and should not normally be shared
 * by multiple threads. If it has to be shared, the calls to set the
 * parameters, calls to add batch statements, the execute call and any
 * post-execute calls should be made within a block synchronized on the
 * PreparedStatement Object.<p>
 *
 * <b>JRE 1.1.x Notes:</b> <p>
 *
 * In general, JDBC 2 support requires Java 1.2 and above, and JDBC3 requires
 * Java 1.4 and above. In HSQLDB, support for methods introduced in different
 * versions of JDBC depends on the JDK version used for compiling and building
 * HSQLDB.<p>
 *
 * Since 1.7.0, it is possible to build the product so that
 * all JDBC 2 methods can be called while executing under the version 1.1.x
 * <em>Java Runtime Environment</em><sup><font size="-2">TM</font></sup>.
 * However, in addition to requiring explicit casts to the org.hsqldb.jdbcXXX
 * interface implementations, some of these method calls require
 * <code>int</code> values that are defined only in the JDBC 2 or greater
 * version of
 * <a href="http://java.sun.com/j2se/1.4/docs/api/java/sql/ResultSet.html">
 * <code>ResultSet</code></a> interface.  For this reason, when the
 * product is compiled under JDK 1.1.x, these values are defined in
 * {@link jdbcResultSet jdbcResultSet}.<p>
 *
 * In a JRE 1.1.x environment, calling JDBC 2 methods that take or return the
 * JDBC2-only <code>ResultSet</code> values can be achieved by referring
 * to them in parameter specifications and return value comparisons,
 * respectively, as follows: <p>
 *
 * <pre class="JavaCodeExample">
 * jdbcResultSet.FETCH_FORWARD
 * jdbcResultSet.TYPE_FORWARD_ONLY
 * jdbcResultSet.TYPE_SCROLL_INSENSITIVE
 * jdbcResultSet.CONCUR_READ_ONLY
 * // etc.
 * </pre>
 *
 * However, please note that code written in such a manner will not be
 * compatible for use with other JDBC 2 drivers, since they expect and use
 * <code>ResultSet</code>, rather than <code>jdbcResultSet</code>.  Also
 * note, this feature is offered solely as a convenience to developers
 * who must work under JDK 1.1.x due to operating constraints, yet wish to
 * use some of the more advanced features available under the JDBC 2
 * specification.<p>
 *
 * (fredt@users)<br>
 * (boucherb@users)
 * </div>
 * <!-- end Release-specific documentation -->
 *
 * @author boucherb@users
 * @author fredt@users
 * @version 1.7.2
 * @see jdbcConnection#prepareStatement
 * @see jdbcResultSet
 */
public class jdbcPreparedStatement extends jdbcStatement
implements PreparedStatement {

    /** The parameter values for the next non-batch execution. */
    protected Object[] parameterValues;

    /** The SQL types of the parameters. */
    protected int[] parameterTypes;

    /** The (IN, IN OUT, or OUT) modes of parameters */
    protected int[] parameterModes;

    /** Lengths for streams. */
    protected int[] streamLengths;

    /** Has a stream or CLOB / BLOB parameter value. */
    protected boolean hasStreams;

    /**
     * Description of result set metadata. <p>
     */
    protected Result rsmdDescriptor;

    /** Description of parameter metadata. */
    protected Result pmdDescriptor;

    /** This object's one and one ResultSetMetaData object. */
    protected jdbcResultSetMetaData rsmd;

// NOTE:  pmd is declared as Object to avoid yet another #ifdef.

    /** This object's one and only ParameterMetaData object. */
    protected Object pmd;

    /** The SQL character sequence that this object represents. */
    protected String sql;

    /**
     * The id with which this object's corresponding
     * {@link org.hsqldb.CompiledStatement CompiledStatement}
     * object is registered in the engine's
     * {@link org.hsqldb.CompiledStatementManager CompiledStatementManager}
     * object.
     */
    protected int statementID;

    /**
     * Whether this statement generates only a single row update count in
     * response to execution.
     */
    protected boolean isRowCount;

// fredt@users 20020215 - patch 517028 by peterhudson@users - method defined
// fredt@users 20020215 - patch 517028 by peterhudson@users - method defined
//
// changes by fredt
// SimpleDateFormat objects moved out of methods to improve performance
// this is safe because only one thread at a time should access a
// PreparedStatement object until it has finished executing the statement
// fredt@users 20020215 - patch 517028 by peterhudson@users - method defined
// minor changes by fredt

    /**
     * <!-- start generic documentation -->
     * Sets escape processing on or off. <p>
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Since 1.7.0, the implementation follows the standard
     * behaviour by overriding the same method in jdbcStatement
     * class. <p>
     *
     * In other words, calling this method has no effect.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param enable <code>true</code> to enable escape processing;
     *     <code>false</code> to disable it
     * @exception SQLException if a database access error occurs
     */
    public void setEscapeProcessing(boolean enable) throws SQLException {
        checkClosed();
    }

    /**
     * <!-- start generic documentation -->
     * Executes the SQL statement in this <code>PreparedStatement</code>
     * object, which may be any kind of SQL statement.
     * Some prepared statements return multiple results; the
     * <code>execute</code> method handles these complex statements as well
     * as the simpler form of statements handled by the methods
     * <code>executeQuery</code>and <code>executeUpdate</code>. <p>
     *
     * The <code>execute</code> method returns a <code>boolean</code> to
     * indicate the form of the first result.  You must call either the method
     * <code>getResultSet</code> or <code>getUpdateCount</code>
     * to retrieve the result; you must call <code>getMoreResults</code> to
     * move to any subsequent result(s). <p>
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Including 1.7.2, prepared statements do not generate
     * multiple fetchable results. <p>
     *
     * Following 1.7.2, it will be possible that statements
     * generate multiple fetchable results under certain conditions.
     * </div>
     *
     * @return <code>true</code> if the first result is a <code>ResultSet</code>
     *    object; <code>false</code> if the first result is an update
     *    count or there is no result