sqlreal.java

derby database source code.good for you.

	/**
	 * @see NumberDataValue#setValue
	 *
	 */
	public void setValue(boolean theValue)
	{
		value = theValue?1:0;
		isnull = false;
	}

	/**
	 * @see DataValueDescriptor#setValue
	 *
	 * @exception StandardException		Thrown on error
	 */	
	public void setValue(Object theValue)
		throws StandardException
	{
		if (theValue == null)
		{
			setToNull();
		}
		else if (theValue instanceof Number)
		{
            // rounding issue to solve!!!/jsk, INF, 0.0f
			this.setValue(((Number)theValue).floatValue());
		}
		else
		{
            // will most likely call .setValue(String)
			genericSetObject(theValue);
		}
	}

	protected void setFrom(DataValueDescriptor theValue) throws StandardException {

            // rounding issue to solve!!!/jsk
            //DOUBLE.getFloat() would make rounding problem if it got called here!!!
            // need to check where it is called from!
            if (theValue instanceof StringDataValue) {
                //System.out.println("\tcalling setValue(string)");
                setValue(theValue.getString());
            } else if (theValue instanceof SQLDouble) {
                //System.out.println("\tcalling setValue(double)");
                setValue(theValue.getDouble());
            } else {
                setValue(theValue.getFloat());
            }
	}


	/*
	 * DataValueDescriptor interface
	 */

	/** @see DataValueDescriptor#typePrecedence */
	public int typePrecedence()
	{
		return TypeId.REAL_PRECEDENCE;
	}


	/*
	** SQL Operators
	*/

	/**
	 * The = operator as called from the language module, as opposed to
	 * the storage module.
	 *
	 * @param left			The value on the left side of the =
	 * @param right			The value on the right side of the =
	 *
	 * @return	A SQL boolean value telling whether the two parameters are equal
	 *
	 * @exception StandardException		Thrown on error
	 */

	public BooleanDataValue equals(DataValueDescriptor left,
							DataValueDescriptor right)
			throws StandardException
	{
		return SQLBoolean.truthValue(left,
									 right,
									 left.getFloat() == right.getFloat());
	}

	/**
	 * The <> operator as called from the language module, as opposed to
	 * the storage module.
	 *
	 * @param left			The value on the left side of the <>
	 * @param right			The value on the right side of the <>
	 *
	 * @return	A SQL boolean value telling whether the two parameters
	 *			are not equal
	 *
	 * @exception StandardException		Thrown on error
	 */

	public BooleanDataValue notEquals(DataValueDescriptor left,
							DataValueDescriptor right)
			throws StandardException
	{
		return SQLBoolean.truthValue(left,
									 right,
									 left.getFloat() != right.getFloat());
	}

	/**
	 * The < operator as called from the language module, as opposed to
	 * the storage module.
	 *
	 * @param left			The value on the left side of the <
	 * @param right			The value on the right side of the <
	 *
	 * @return	A SQL boolean value telling whether the first operand is less
	 *			than the second operand
	 *
	 * @exception StandardException		Thrown on error
	 */

	public BooleanDataValue lessThan(DataValueDescriptor left,
							DataValueDescriptor right)
			throws StandardException
	{
		return SQLBoolean.truthValue(left,
									 right,
									 left.getFloat() < right.getFloat());
	}

	/**
	 * The > operator as called from the language module, as opposed to
	 * the storage module.
	 *
	 * @param left			The value on the left side of the >
	 * @param right			The value on the right side of the >
	 *
	 * @return	A SQL boolean value telling whether the first operand is greater
	 *			than the second operand
	 *
	 * @exception StandardException		Thrown on error
	 */

	public BooleanDataValue greaterThan(DataValueDescriptor left,
							DataValueDescriptor right)
			throws StandardException
	{
		return SQLBoolean.truthValue(left,
									 right,
									 left.getFloat() > right.getFloat());
	}

	/**
	 * The <= operator as called from the language module, as opposed to
	 * the storage module.
	 *
	 * @param left			The value on the left side of the <=
	 * @param right			The value on the right side of the <=
	 *
	 * @return	A SQL boolean value telling whether the first operand is less
	 *			than or equal to the second operand
	 *
	 * @exception StandardException		Thrown on error
	 */

	public BooleanDataValue lessOrEquals(DataValueDescriptor left,
							DataValueDescriptor right)
			throws StandardException
	{
		return SQLBoolean.truthValue(left,
									 right,
									 left.getFloat() <= right.getFloat());
	}

	/**
	 * The >= operator as called from the language module, as opposed to
	 * the storage module.
	 *
	 * @param left			The value on the left side of the >=
	 * @param right			The value on the right side of the >=
	 *
	 * @return	A SQL boolean value telling whether the first operand is greater
	 *			than or equal to the second operand
	 *
	 * @exception StandardException		Thrown on error
	 */

	public BooleanDataValue greaterOrEquals(DataValueDescriptor left,
							DataValueDescriptor right)
			throws StandardException
	{
		return SQLBoolean.truthValue(left,
									 right,
									 left.getFloat() >= right.getFloat());
	}


	/**
	 * This method implements the + operator for "real + real".
     * The operator uses DOUBLE aritmetic as DB2 does.
	 *
	 * @param addend1	One of the addends
	 * @param addend2	The other addend
	 * @param result	The result of a previous call to this method, null
	 *					if not called yet
	 *
	 * @return	A SQLReal containing the result of the addition
	 *
	 * @exception StandardException		Thrown on error
	 */

	public NumberDataValue plus(NumberDataValue addend1,
							NumberDataValue addend2,
							NumberDataValue result)
				throws StandardException
	{
		if (result == null)
		{
			result = new SQLReal();
		}

		if (addend1.isNull() || addend2.isNull())
		{
			result.setToNull();
			return result;
		}

        double dsum = addend1.getDouble() + addend2.getDouble();
        // No need to check underflow (result rounded to 0.0),
        // since the difference between two non-equal valid DB2 DOUBLE values is always non-zero in java.lang.Double precision.
        result.setValue(dsum);

		return result;
	}

	/**
	 * This method implements the - operator for "real - real".
     * The operator uses DOUBLE aritmetic as DB2 does.
	 *
	 * @param left	The value to be subtracted from
	 * @param right	The value to be subtracted
	 * @param result	The result of a previous call to this method, null
	 *					if not called yet
	 *
	 * @return	A SQLReal containing the result of the subtraction
	 *
	 * @exception StandardException		Thrown on error
	 */

	public NumberDataValue minus(NumberDataValue left,
							NumberDataValue right,
							NumberDataValue result)
				throws StandardException
	{
		if (result == null)
		{
			result = new SQLReal();
		}

		if (left.isNull() || right.isNull())
		{
			result.setToNull();
			return result;
		}

		double ddifference = left.getDouble() - right.getDouble();
        // No need to check underflow (result rounded to 0.0),
        // since no difference between two valid DB2 DOUBLE values can be rounded off to 0.0 in java.lang.Double
		result.setValue(ddifference);
		return result;
	}

	/**
	 * This method implements the * operator for "real * real".
     * The operator uses DOUBLE aritmetic as DB2 does.
	 *
	 * @param left	The first value to be multiplied
	 * @param right	The second value to be multiplied
	 * @param result	The result of a previous call to this method, null
	 *					if not called yet
	 *
	 * @return	A SQLReal containing the result of the multiplication
	 *
	 * @exception StandardException		Thrown on error
	 */

	public NumberDataValue times(NumberDataValue left,
							NumberDataValue right,
							NumberDataValue result)
				throws StandardException
	{
		if (result == null)
		{
			result = new SQLReal();
		}

		if (left.isNull() || right.isNull())
		{
			result.setToNull();
			return result;
		}

        double leftValue = left.getDouble();
        double rightValue = right.getDouble();
		double tempResult = leftValue * rightValue;
        // check underflow (result rounded to 0.0)
        if ( (tempResult == 0.0) && ( (leftValue != 0.0) && (rightValue != 0.0) ) ) {
			throw StandardException.newException(SQLState.LANG_OUTSIDE_RANGE_FOR_DATATYPE, TypeId.REAL_NAME);
        }

		result.setValue(tempResult);
		return result;
	}

	/**
	 * This method implements the / operator for "real / real".
     * The operator uses DOUBLE aritmetic as DB2 does.
	 *
	 * @param dividend	The numerator
	 * @param divisor	The denominator
	 * @param result	The result of a previous call to this method, null
	 *					if not called yet
	 *
	 * @return	A SQLReal containing the result of the division
	 *
	 * @exception StandardException		Thrown on error
	 */

	public NumberDataValue divide(NumberDataValue dividend,
							 NumberDataValue divisor,
							 NumberDataValue result)
				throws StandardException
	{
		if (result == null)
		{
			result = new SQLReal();
		}

		if (dividend.isNull() || divisor.isNull())
		{
			result.setToNull();
			return result;
		}

		double divisorValue = divisor.getDouble();
		if (divisorValue == 0.0e0f)
		{
			throw StandardException.newException(SQLState.LANG_DIVIDE_BY_ZERO);
		}

        double dividendValue = dividend.getDouble();
		double resultValue = dividendValue / divisorValue;
		if (Double.isNaN(resultValue))
		{
			throw StandardException.newException(SQLState.LANG_DIVIDE_BY_ZERO);
		}

        // check underflow (result rounded to 0.0)
        if ((resultValue == 0.0e0d) && (dividendValue != 0.0e0d)) {
			throw StandardException.newException(SQLState.LANG_OUTSIDE_RANGE_FOR_DATATYPE, TypeId.REAL_NAME);
        }

		result.setValue(resultValue);
		return result;
	}

	/**
	 * This method implements the unary minus operator for real.
	 *
	 * @param result	The result of a previous call to this method, null
	 *					if not called yet
	 *
	 * @return	A SQLSmalllint containing the result of the division
	 *
	 * @exception StandardException		Thrown on error
	 */

	public NumberDataValue minus(NumberDataValue result)
									throws StandardException
	{
		float		minusResult;

		if (result == null)
		{
			result = new SQLReal();
		}

		if (this.isNull())
		{
			result.setToNull();
			return result;
		}

		minusResult = -(this.getFloat());
		result.setValue(minusResult);
		return result;
	}

    /**
     * This method implements the isNegative method.
     * Note: This method will return true for -0.0f.
     *
     * @return  A boolean.  If this.value is negative, return true.
     *          For positive values or null, return false.
     */

    protected boolean isNegative()
    {
        return !isNull() && (value < 0.0f);
    }

	/*
	 * String display of value
	 */

	public String toString()
	{
		if (isNull())
			return "NULL";
		else
			return Float.toString(value);
	}

	/*
	 * Hash code
	 */
	public int hashCode()
	{
		long longVal = (long) value;

		if (longVal != value)
		{
			longVal = Double.doubleToLongBits(value);
		}

		return (int) (longVal ^ (longVal >> 32));	
	}

	static final int REAL_LENGTH = 16;

    private static final int BASE_MEMORY_USAGE = ClassSize.estimateBaseFromCatalog( SQLReal.class);

    public int estimateMemoryUsage()
    {
        return BASE_MEMORY_USAGE;
    }

	/*
	 * object state
	 */
	private float value;
	private boolean isnull;

}