org.firebirdsql.gds.ng.fields

Interface BlrCalculator

All Known Implementing Classes:

DefaultBlrCalculator

public interface BlrCalculator

Interface for calculating the blr (binary language representation) of a row.

Since:

3.0

Author:

Mark Rotteveel

Method Summary

Modifier and Type	Method and Description
byte[]	calculateBlr(RowDescriptor rowDescriptor) Calculates the blr for the row descriptor.
byte[]	calculateBlr(RowDescriptor rowDescriptor, RowValue rowValue) Calculates the blr for a specific row value.
int	calculateIoLength(FieldDescriptor fieldDescriptor) Calculates the io length for the field descriptor.
int	calculateIoLength(FieldDescriptor fieldDescriptor, FieldValue fieldValue) Calculates the io length for the field descriptor.

Method Detail

calculateBlr

byte[] calculateBlr(RowDescriptor rowDescriptor)
             throws java.sql.SQLException

Calculates the blr for the row descriptor.

Parameters:

rowDescriptor - Row descriptor

Returns:

Byte array with the blr

Throws:

java.sql.SQLException - When the RowDescriptor contains an unsupported field type.

calculateBlr

byte[] calculateBlr(RowDescriptor rowDescriptor,
                    RowValue rowValue)
             throws java.sql.SQLException

Calculates the blr for a specific row value.

This allows to optimize for the actual length of the field.

Parameters:

rowDescriptor - Row descriptor

rowValue - Row value

Returns:

Byte array with the blr

Throws:

java.sql.SQLException - When the RowValue contains an unsupported field type.

calculateIoLength

int calculateIoLength(FieldDescriptor fieldDescriptor)
               throws java.sql.SQLException

Calculates the io length for the field descriptor.

The return value indicates the length and padding of the type in the buffer

• < 0 : Type is of specified length * -1 and not padded
• == 0 : Type is of dynamic length (which is specified in the buffer as an integer) and padded
• > 0 : Type is of specified length minus 1 (subtracting 1 is required to avoid 0 for types of zero length) and padded

Parameters:

fieldDescriptor - Field descriptor

Returns:

The io length

Throws:

java.sql.SQLException

calculateIoLength

int calculateIoLength(FieldDescriptor fieldDescriptor,
                      FieldValue fieldValue)
               throws java.sql.SQLException

Calculates the io length for the field descriptor.

The return value indicates the length and padding of the type in the buffer

• < 0 : Type is of specified length * -1 and not padded
• == 0 : Type is of dynamic length (which is specified in the buffer as an integer) and padded
• > 0 : Type is of specified length minus 1 (subtracting 1 is required to avoid 0 for types of zero length) nd padded

This allows to optimize for the actual length of the field.

For CHAR (ISCConstants.SQL_TEXT the implementation should be consistent with the lengths as given by calculateBlr(RowDescriptor, RowValue).

Parameters:

fieldDescriptor - Field descriptor

fieldValue - Field value

Returns:

The io length

Throws:

java.sql.SQLException