column.java

hsqldb是100％java实现的数据库,是一个开放源代码的JAVA数据库 l 具有标准的SQL语法和JAVA接口 l HSQLDB可以自由使用和分发 l 非常简洁和快速的

                           int type) throws HsqlException {

        if (a == null || b == null) {
            return null;
        }

// fredt@users - type conversion - may need to apply to other arithmetic operations too
        if (!(a instanceof Number && b instanceof Number)) {
            a = Column.convertObject(a, type);
            b = Column.convertObject(b, type);
        }

        switch (type) {

            case Types.NULL :
                return null;

            case Types.REAL :
            case Types.FLOAT :
            case Types.DOUBLE : {
                double ad = ((Number) a).doubleValue();
                double bd = ((Number) b).doubleValue();

                return ValuePool.getDouble(Double.doubleToLongBits(ad * bd));
            }
            case Types.NUMERIC :
            case Types.DECIMAL : {
                BigDecimal abd = (BigDecimal) a;
                BigDecimal bbd = (BigDecimal) b;

                return abd.multiply(bbd);
            }
            case Types.TINYINT :
            case Types.SMALLINT :
            case Types.INTEGER : {
                int ai = ((Number) a).intValue();
                int bi = ((Number) b).intValue();

                return ValuePool.getInt(ai * bi);
            }
            case Types.BIGINT : {
                long longa = ((Number) a).longValue();
                long longb = ((Number) b).longValue();

                return ValuePool.getLong(longa * longb);
            }
            default :
                throw Trace.error(Trace.FUNCTION_NOT_SUPPORTED,
                                  Types.getTypeString(type));
        }
    }

    /**
     *  Divide numeric object a by object b.
     *
     * @param  a
     * @param  b
     * @param  type
     * @return result
     * @throws  HsqlException
     */
    static Object divide(Object a, Object b, int type) throws HsqlException {

        if (a == null || b == null) {
            return null;
        }

        switch (type) {

            case Types.NULL :
                return null;

            case Types.REAL :
            case Types.FLOAT :
            case Types.DOUBLE : {
                double ad = ((Number) a).doubleValue();
                double bd = ((Number) b).doubleValue();

                return ValuePool.getDouble(Double.doubleToLongBits(ad / bd));
            }
            case Types.NUMERIC :
            case Types.DECIMAL : {
                BigDecimal abd   = (BigDecimal) a;
                BigDecimal bbd   = (BigDecimal) b;
                int        scale = abd.scale() > bbd.scale() ? abd.scale()
                                                             : bbd.scale();

                return (bbd.signum() == 0) ? null
                                           : abd.divide(bbd, scale,
                                           BigDecimal.ROUND_HALF_DOWN);
            }
            case Types.TINYINT :
            case Types.SMALLINT :
            case Types.INTEGER : {
                int ai = ((Number) a).intValue();
                int bi = ((Number) b).intValue();

                if (bi == 0) {
                    throw Trace.error(Trace.DIVISION_BY_ZERO);
                }

                return ValuePool.getInt(ai / bi);
            }
            case Types.BIGINT : {
                long longa = ((Number) a).longValue();
                long longb = ((Number) b).longValue();

                return (longb == 0) ? null
                                    : ValuePool.getLong(longa / longb);
            }
            default :
                throw Trace.error(Trace.FUNCTION_NOT_SUPPORTED,
                                  Types.getTypeString(type));
        }
    }

    /**
     *  Subtract numeric object b from object a.
     *
     * @param  a
     * @param  b
     * @param  type
     * @return result
     * @throws  HsqlException
     */
    static Object subtract(Object a, Object b,
                           int type) throws HsqlException {

        if (a == null || b == null) {
            return null;
        }

        switch (type) {

            case Types.NULL :
                return null;

            case Types.REAL :
            case Types.FLOAT :
            case Types.DOUBLE : {
                double ad = ((Number) a).doubleValue();
                double bd = ((Number) b).doubleValue();

                return ValuePool.getDouble(Double.doubleToLongBits(ad - bd));
            }
            case Types.NUMERIC :
            case Types.DECIMAL : {
                BigDecimal abd = (BigDecimal) a;
                BigDecimal bbd = (BigDecimal) b;

                return abd.subtract(bbd);
            }
            case Types.TINYINT :
            case Types.SMALLINT :
            case Types.INTEGER : {
                int ai = ((Number) a).intValue();
                int bi = ((Number) b).intValue();

                return ValuePool.getInt(ai - bi);
            }
            case Types.BIGINT : {
                long longa = ((Number) a).longValue();
                long longb = ((Number) b).longValue();

                return ValuePool.getLong(longa - longb);
            }
            default :
                throw Trace.error(Trace.FUNCTION_NOT_SUPPORTED,
                                  Types.getTypeString(type));
        }
    }

// boucherb@users 2003-09-25
// TODO:  Maybe use //#ifdef tag or reflective static method attribute
// instantiation to take advantage of String.compareToIgnoreCase when
// available (JDK 1.2 and greater) during ANT build. That or perhaps
// consider using either local character-wise comparison or first converting
// to lower case and then to upper case. Sun states that the JDK 1.2 introduced
// String.compareToIngnorCase() comparison involves calling
// Character.toLowerCase(Character.toUpperCase()) on compared characters,
// to correctly handle some caveats concering using only the one operation or
// the other outside the ascii character range.
// fredt@users 20020130 - patch 418022 by deforest@users
// use of rtrim() to mimic SQL92 behaviour

    /**
     *  Compare a with b and return int value as result.
     *
     * @param  a instance of Java wrapper, depending on type, but always same for a & b (can be null)
     * @param  b instance of Java wrapper, depending on type, but always same for a & b (can be null)
     * @param  type one of the java.sql.Types
     * @return result 1 if a>b, 0 if a=b, -1 if b>a
     * @throws  HsqlException
     */
    static int compare(Collation collation, Object a, Object b, int type) {

        int i = 0;

        if (a == b) {
            return 0;
        }

        // Current null handling here: null==null and smaller any value
        // Note, standard SQL null handling is handled by Expression.test() calling testNull() instead of this!
        // Attention, this is also used for grouping ('null' is one group)
        if (a == null) {
            return -1;
        }

        if (b == null) {
            return 1;
        }

        switch (type) {

            case Types.NULL :
                return 0;

            case Types.VARCHAR :
            case Types.LONGVARCHAR :
                return collation.compare((String) a, (String) b);

            case Types.CHAR :
                return collation.compare(Library.rtrim((String) a),
                                         Library.rtrim((String) b));

            case Types.VARCHAR_IGNORECASE :
                return collation.compareIgnoreCase(((String) a),
                                                   ((String) b));

            case Types.TINYINT :
            case Types.SMALLINT :
            case Types.INTEGER : {
                int ai = ((Number) a).intValue();
                int bi = ((Number) b).intValue();

                return (ai > bi) ? 1
                                 : (bi > ai ? -1
                                            : 0);
            }
            case Types.BIGINT : {
                long longa = ((Number) a).longValue();
                long longb = ((Number) b).longValue();

                return (longa > longb) ? 1
                                       : (longb > longa ? -1
                                                        : 0);
            }
            case Types.REAL :
            case Types.FLOAT :
            case Types.DOUBLE : {
                double ad = ((Number) a).doubleValue();
                double bd = ((Number) b).doubleValue();

                return (ad > bd) ? 1
                                 : (bd > ad ? -1
                                            : 0);
            }
            case Types.NUMERIC :
            case Types.DECIMAL :
                i = ((BigDecimal) a).compareTo((BigDecimal) b);
                break;

            case Types.DATE :
                return HsqlDateTime.compare((Date) a, (Date) b);

            case Types.TIME :
                return HsqlDateTime.compare((Time) a, (Time) b);

            case Types.TIMESTAMP :
                return HsqlDateTime.compare((Timestamp) a, (Timestamp) b);

            case Types.BOOLEAN : {
                boolean boola = ((Boolean) a).booleanValue();
                boolean boolb = ((Boolean) b).booleanValue();

                return (boola == boolb) ? 0
                                        : (boolb ? -1
                                                 : 1);
            }
            case Types.BINARY :
            case Types.VARBINARY :
            case Types.LONGVARBINARY :
                if (a instanceof Binary && b instanceof Binary) {
                    i = compareTo(((Binary) a).getBytes(),
                                  ((Binary) b).getBytes());
                }
                break;

            case Types.OTHER :
                return 0;
        }

        return (i == 0) ? 0
                        : (i < 0 ? -1
                                 : 1);
    }

    /**
     *  Convert an object into a Java object that represents its SQL type.<p>
     *  All internal type conversion operations start with
     *  this method. If a direct conversion doesn't take place, the object
     *  is converted into a string first and an attempt is made to convert
     *  the string into the target type.<br>
     *
     *  One objective of this mehod is to ensure the Object can be converted
     *  to the given SQL type. For example, a very large BIGINT
     *  value cannot be narrowed down to an INTEGER or SMALLINT.<br>
     *
     *  Type conversion performed by this method has gradually evolved in 1.7.2
     *  to allow narrowing of numeric types in all cases according to the SQL
     *  standard.<br>
     *
     *  Another new objective is to normalize DATETIME values.<br>
     *
     *  Objects set via JDBC PreparedStatement use this method to convert
     *  the data to the Java type that is required for custom serialization
     *  by the engine. <br>
     *
     * @param  o
     * @param  type
     * @return result
     * @throws  HsqlException
     */
    public static Object convertObject(Object o,
                                       int type) throws HsqlException {

        try {
            if (o == null) {
                return null;
            }

            switch (type) {

                case Types.NULL :
                    return null;

                case Types.TINYINT :
                    if (o instanceof java.lang.String) {
                        o = Library.trim((String) o, " ", true, true);

                        int val = Integer.parseInt((String) o);

                        o = ValuePool.getInt(val);
                    }

                    if (o instanceof java.lang.Integer) {
                        int temp = ((Number) o).intValue();

                        if (Byte.MAX_VALUE < temp || temp < Byte.MIN_VALUE) {
                            throw Trace.error(
                                Trace.NUMERIC_VALUE_OUT_OF_RANGE);
                        }

                        return o;
                    }

                    if (o instanceof java.lang.Long) {
                        long temp = ((Number) o).longValue();

                        if (Byte.MAX_VALUE < temp || temp < Byte.MIN_VALUE) {
                            throw Trace.error(
                                Trace.NUMERIC_VALUE_OUT_OF_RANGE);
                        }

                        return ValuePool.getInt(((Number) o).intValue());
                    }

                    // fredt@users - direct conversion to optimise JDBC setObject(Byte)
                    if (o instanceof java.lang.Byte) {
                        return ValuePool.getInt(((Number) o).intValue());
                    }

                    // fredt@users - returns to this method for range checking
                    if (o instanceof java.lang.Number) {
                        return convertObject(convertToInt(o), type);
                    }

                    if (o instanceof java.lang.Boolean) {
                        return ((Boolean) o).booleanValue()
                               ? ValuePool.getInt(1)
                               : ValuePool.getInt(0);
                    }
                    break;

                case Types.SMALLINT :
                    if (o instanceof java.lang.String) {
                        o = Library.trim((String) o, " ", true, true);

                        int val = Integer.parseInt((String) o);

                        o = ValuePool.getInt(val);
                    }

                    if (o instanceof java.lang.Integer) {
                        int temp = ((Number) o).intValue();

                        if (Short.MAX_VALUE < temp
                                || temp < Short.MIN_VALUE) {
                            throw Trace.error(
                                Trace.NUMERIC_VALUE_OUT_OF_RANGE);
                        }

                        return o;
                    }

                    if (o instanceof java.lang.Long) {
                        long temp = ((Number) o).longValue();

                        if (Short.MAX_VALUE < temp
                                || temp < Short.MIN_VALUE) {
                            throw Trace.error(
                                Trace.NUMERIC_VALUE_OUT_OF_RANGE);
                        }

                        return ValuePool.getInt(((Number) o).intValue());
                    }

                    // fredt@users - direct conversion for JDBC setObject(Short), etc.
                    if (o instanceof Byte || o instanceof Short) {
                        return ValuePool.getInt(((Number) o).intValue());
                    }

                    // fredt@users - returns to this method for range checking
                    if (o instanceof Number) {
                        return convertObject(convertToInt(o), type);
                    }

                    if (o instanceof java.lang.Boolean) {
                        return ((Boolean) o).booleanValue()
                               ? ValuePool.getInt(1)
                               : ValuePool.getInt(0);
                    }
                    break;

                case Types.INTEGER :
                    if (o instanceof java.lang.Integer) {
                        return o;
                    }

                    if (o instanceof java.lang.String) {
                        o = Library.trim((String) o, " ", true, true);

                        int val = Integer.parseInt((String) o);

                        return ValuePool.getInt(val);
                    }

                    if (o instanceof java.lang.Long) {
                        long temp = ((Number) o).longValue();

                        if (Integer.MAX_VALUE < temp
                                || temp < Integer.MIN_VALUE) {
                            throw Trace.error(
                                Trace.NUMERIC_VALUE_OUT_OF_RANGE);
                        }

                        return ValuePool.getInt(((Number) o).intValue());
                    }

                    if (o instanceof Byte || o instanceof Short) {
                        return ValuePool.getInt(((Number) o).intValue());
                    }

                    if (o instanceof java.lang.Number) {
                        return convertToInt(o);
                    }

                    if (o instanceof java.lang.Boolean) {
                        return ((Boolean) o).booleanValue()
                               ? ValuePool.getInt(1)
                               : ValuePool.getInt(0);
                    }
                    break;