org.firebirdsql.gds.ng.wire

Class DefaultBlrCalculator

java.lang.Object

org.firebirdsql.gds.ng.wire.DefaultBlrCalculator

All Implemented Interfaces:

BlrCalculator

public class DefaultBlrCalculator
extends java.lang.Object
implements BlrCalculator

Default BLR calculator for the wire protocol.

Most likely this can be used without change for other protocol versions as well, although we may need to investigate the TODOs specified in calculateBlr(org.firebirdsql.gds.ng.fields.RowDescriptor).

Since:

3.0

Author:

Mark Rotteveel

Field Summary

Fields

Modifier and Type	Field and Description
static DefaultBlrCalculator	CALCULATOR_DIALECT_3 Cached instance of DefaultBlrCalculator for dialect 3 databases.

Constructor Summary

Constructors

Constructor and Description
DefaultBlrCalculator(short dialect)

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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CALCULATOR_DIALECT_3

public static final DefaultBlrCalculator CALCULATOR_DIALECT_3

Cached instance of DefaultBlrCalculator for dialect 3 databases.

Constructor Detail

DefaultBlrCalculator

public DefaultBlrCalculator(short dialect)

Method Detail

calculateBlr

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

Description copied from interface: BlrCalculator

Calculates the blr for the row descriptor.

Specified by:

calculateBlr in interface BlrCalculator

Parameters:

rowDescriptor - Row descriptor

Returns:

Byte array with the blr

Throws:

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

calculateBlr

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

Description copied from interface: BlrCalculator

Calculates the blr for a specific row value.

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

Specified by:

calculateBlr in interface BlrCalculator

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

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

Description copied from interface: BlrCalculator

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

Specified by:

calculateIoLength in interface BlrCalculator

Parameters:

fieldDescriptor - Field descriptor

Returns:

The io length

Throws:

java.sql.SQLException

calculateIoLength

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

Description copied from interface: BlrCalculator

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 BlrCalculator.calculateBlr(RowDescriptor, RowValue).

Specified by:

calculateIoLength in interface BlrCalculator

Parameters:

fieldDescriptor - Field descriptor

fieldValue - Field value

Returns:

The io length

Throws:

java.sql.SQLException