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HSQLDB example source code file (jdbcParameterMetaData.java)

This example HSQLDB source code file (jdbcParameterMetaData.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - HSQLDB tags/keywords

boolean, exception, integer, jdbc, method, method, object, parametermetadata, reflection, sql, sqlexception, sqlexception, string, string, stringbuffer, stringbuffer, throwable

The HSQLDB jdbcParameterMetaData.java source code

/* Copyright (c) 2001-2008, 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
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb.jdbc;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.sql.ParameterMetaData;
import java.sql.SQLException;

import org.hsqldb.Result;
import org.hsqldb.Trace;
import org.hsqldb.Types;

// fredt@users 20040412 - removed DITypeInfo dependencies
// TODO: implement internal support for at least OUT return parameter

/**
 * An object that can be used to get information about the types and
 * properties of the parameters in a PreparedStatement object.
 *
 * @author boucherb@users
 * @version 1.7.2
 * @since JDK 1.4, HSQLDB 1.7.2
 */
public class jdbcParameterMetaData implements ParameterMetaData {

    /** The metadata object with which this object is constructed */
    Result.ResultMetaData rmd;

    /** The numeric data type codes of the parameters. */
    int[] types;

    /** Parameter mode values */
    int[] modes;

    /** whether param is assigned directly to identity column */
    boolean[] isIdentity;

    /** nullability code for site to which param is bound */
    int[] nullability;

    /**
     * The fully-qualified name of the Java class whose instances should
     * be passed to the method PreparedStatement.setObject. <p>
     *
     * Note that changes to Function.java and Types.java allow passing
     * objects of any class implementing java.io.Serializable and that,
     * as such, the parameter expression resolution mechanism has been
     * upgraded to provide the precise FQN for SQL function and stored
     * procedure arguments, rather than the more generic
     * org.hsqldb.JavaObject class that is used internally to represent
     * and transport objects whose class is not in the standard mapping.
     */
    String[] classNames;

    /** The number of parameters in the described statement */
    int parameterCount;

    /**
     * Creates a new instance of jdbcParameterMetaData. <p>
     *
     * @param r A Result object describing the statement parameters
     * @throws SQLException never - reserved for future use
     */
    jdbcParameterMetaData(Result r) throws SQLException {

        if (r == null) {
            parameterCount = 0;

            return;
        }

        rmd            = r.metaData;
        types          = rmd.colTypes;
        parameterCount = types.length;
        nullability    = rmd.colNullable;
        isIdentity     = rmd.isIdentity;
        classNames     = rmd.classNames;
        modes          = rmd.paramMode;
    }

    /**
     * Checks if the value of the param argument is a valid parameter
     * position. <p>
     *
     * @param param position to check
     * @throws SQLException if the value of the param argument is not a
     *      valid parameter position
     */
    void checkRange(int param) throws SQLException {

        if (param < 1 || param > parameterCount) {
            String msg = param + " is out of range";

            throw Util.sqlException(Trace.INVALID_JDBC_ARGUMENT, msg);
        }
    }

    /**
     * Retrieves the fully-qualified name of the Java class whose instances
     * should be passed to the method PreparedStatement.setObject. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return the fully-qualified name of the class in the
     *        Java programming language that would be
     *        used by the method PreparedStatement.setObject
     *        to set the value in the specified parameter.
     *        This is the class name used for custom mapping.
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public String getParameterClassName(int param) throws SQLException {

        checkRange(param);

        return classNames[--param];
    }

    /**
     * Retrieves the number of parameters in the PreparedStatement object for
     * which this ParameterMetaData object provides information. <p>
     *
     * @throws SQLException if a database access error occurs
     * @return the number of parameters
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public int getParameterCount() throws SQLException {
        return parameterCount;
    }

    /**
     * Retrieves the designated parameter's mode. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return mode of the parameter; one of
     *        ParameterMetaData.parameterModeIn,
     *        ParameterMetaData.parameterModeOut,
     *        ParameterMetaData.parameterModeInOut,
     *        ParameterMetaData.parameterModeUnknown
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public int getParameterMode(int param) throws SQLException {

        checkRange(param);

        return modes[--param];
    }

    /**
     * Retrieves the designated parameter's SQL type. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return SQL type from java.sql.Types
     * @since JDK 1.4, HSQLDB 1.7.2
     * @see java.sql.Types
     */
    public int getParameterType(int param) throws SQLException {

        int t;

        checkRange(param);

        t = types[--param];

        return t == Types.VARCHAR_IGNORECASE ? Types.VARCHAR
                                             : t;
    }

    /**
     * Retrieves the designated parameter's database-specific type name. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return type the name used by the database.
     *        If the parameter type is a user-defined
     *        type, then a fully-qualified type name is
     *        returned.
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public String getParameterTypeName(int param) throws SQLException {

        int t;
        int ts;

        checkRange(param);

        return Types.getTypeName(types[--param]);
    }

    /**
     * Retrieves the designated parameter's number of decimal digits. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return precision
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public int getPrecision(int param) throws SQLException {

        checkRange(param);

        // TODO:
        // parameters assigned directly to table columns
        // should report the precision of the column if it is
        // defined, otherwise the default (intrinsic) precision
        // of the undecorated type
        return Types.getPrecision(types[--param]);
    }

    /**
     * Retrieves the designated parameter's number of digits to right of
     * the decimal point. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return scale
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public int getScale(int param) throws SQLException {

        checkRange(param);

        // TODO:
        // parameters assigned directly to DECIMAL/NUMERIC columns
        // should report the declared scale of the column
        // For now, to be taken as "default or unknown"
        return 0;
    }

    /**
     * Retrieves whether null values are allowed in the designated parameter. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return the nullability status of the given parameter; one of
     *        ParameterMetaData.parameterNoNulls,
     *        ParameterMetaData.parameterNullable or
     *        ParameterMetaData.parameterNullableUnknown
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public int isNullable(int param) throws SQLException {

        checkRange(param);

        return nullability[--param];
    }

    /**
     * Retrieves whether values for the designated parameter can be
     * signed numbers. <p>
     *
     * @param param the first parameter is 1, the second is 2, ...
     * @throws SQLException if a database access error occurs
     * @return true if so; false otherwise
     * @since JDK 1.4, HSQLDB 1.7.2
     */
    public boolean isSigned(int param) throws SQLException {

        checkRange(param);

        Boolean b = Types.isUnsignedAttribute(types[--param]);

        return b != null &&!b.booleanValue() &&!isIdentity[param];
    }

    /**
     * Retrieves a String repsentation of this object. <p>
     *
     * @return a String repsentation of this object
     */
    public String toString() {

        try {
            return toStringImpl();
        } catch (Throwable t) {
            return super.toString() + "[toStringImpl_exception=" + t + "]";
        }
    }

    /**
     * Provides the implementation of the toString() method. <p>
     *
     * @return a String representation of this object
     * @throws Exception if a reflection error occurs
     */
    private String toStringImpl() throws Exception {

        StringBuffer sb;
        Method[]     methods;
        Method       method;
        int          count;

        sb = new StringBuffer();

        sb.append(super.toString());

        count = getParameterCount();

        if (count == 0) {
            sb.append("[parameterCount=0]");

            return sb.toString();
        }

        methods = getClass().getDeclaredMethods();

        sb.append('[');

        int len = methods.length;

        for (int i = 0; i < count; i++) {
            sb.append('\n');
            sb.append("    parameter_");
            sb.append(i + 1);
            sb.append('=');
            sb.append('[');

            for (int j = 0; j < len; j++) {
                method = methods[j];

                if (!Modifier.isPublic(method.getModifiers())) {
                    continue;
                }

                if (method.getParameterTypes().length != 1) {
                    continue;
                }

                sb.append(method.getName());
                sb.append('=');
                sb.append(method.invoke(this,
                                        new Object[]{ new Integer(i + 1) }));

                if (j + 1 < len) {
                    sb.append(',');
                    sb.append(' ');
                }
            }

            sb.append(']');

            if (i + 1 < count) {
                sb.append(',');
                sb.append(' ');
            }
        }

        sb.append('\n');
        sb.append(']');

        return sb.toString();
    }

//#ifdef JAVA6
/*
    public <T> T unwrap(Class iface) throws SQLException
    {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public boolean isWrapperFor(Class<?> iface) throws SQLException
    {
        throw new UnsupportedOperationException("Not supported yet.");
    }
*/

//#endif JAVA6
}

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