org.apache.hadoop.hbase.types

Class FixedLengthWrapper<T>

java.lang.Object

org.apache.hadoop.hbase.types.FixedLengthWrapper<T>

All Implemented Interfaces:

DataType<T>

Direct Known Subclasses:

RawBytesFixedLength, RawStringFixedLength

@InterfaceAudience.Public
public class FixedLengthWrapper<T>
extends Object
implements DataType<T>

Wraps an existing DataType implementation as a fixed-length version of itself. This has the useful side-effect of turning an existing DataType which is not skippable into a skippable variant.

Field Summary

Fields

Modifier and Type	Field and Description
protected DataType<T>	base
protected int	length

Constructor Summary

Constructors

Constructor and Description
FixedLengthWrapper(DataType<T> base, int length) Create a fixed-length version of the wrapped.

Method Summary

Modifier and Type	Method and Description
T	decode(PositionedByteRange src) Read an instance of T from the buffer src.
int	encode(PositionedByteRange dst, T val) Write instance val into buffer dst.
Class<T>	encodedClass() Inform consumers over what type this DataType operates.
int	encodedLength(T val) Inform consumers how long the encoded byte[] will be.
int	getLength() Retrieve the maximum length (in bytes) of encoded values.
Order	getOrder() Retrieve the sort Order imposed by this data type, or null when natural ordering is not preserved.
boolean	isNullable() Indicates whether this instance supports encoding null values.
boolean	isOrderPreserving() Indicates whether this instance writes encoded byte[]'s which preserve the natural sort order of the unencoded value.
boolean	isSkippable() Indicates whether this instance is able to skip over it's encoded value.
int	skip(PositionedByteRange src) Skip src's position forward over one encoded value.

Methods inherited from class java.lang.Object

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

Field Detail

base

protected final DataType<T> base

length

protected final int length

Constructor Detail

FixedLengthWrapper

public FixedLengthWrapper(DataType<T> base,
                          int length)

Create a fixed-length version of the wrapped.

Parameters:

base - the DataType to restrict to a fixed length.

length - the maximum length (in bytes) for encoded values.

Method Detail

getLength

public int getLength()

Retrieve the maximum length (in bytes) of encoded values.

isOrderPreserving

public boolean isOrderPreserving()

Description copied from interface: DataType

Indicates whether this instance writes encoded byte[]'s which preserve the natural sort order of the unencoded value.

Specified by:

isOrderPreserving in interface DataType<T>

Returns:

true when natural order is preserved, false otherwise.

getOrder

public Order getOrder()

Description copied from interface: DataType

Retrieve the sort Order imposed by this data type, or null when natural ordering is not preserved. Value is either ascending or descending. Default is assumed to be Order.ASCENDING.

Specified by:

getOrder in interface DataType<T>

isNullable

public boolean isNullable()

Description copied from interface: DataType

Indicates whether this instance supports encoding null values. This depends on the implementation details of the encoding format. All DataTypes that support null should treat null as comparing less than any non-null value for default sort ordering purposes.

Specified by:

isNullable in interface DataType<T>

Returns:

true when null is supported, false otherwise.

isSkippable

public boolean isSkippable()

Description copied from interface: DataType

Indicates whether this instance is able to skip over it's encoded value. DataTypes that are not skippable can only be used as the right-most field of a Struct.

Specified by:

isSkippable in interface DataType<T>

encodedLength

public int encodedLength(T val)

Description copied from interface: DataType

Inform consumers how long the encoded byte[] will be.

Specified by:

encodedLength in interface DataType<T>

Parameters:

val - The value to check.

Returns:

the number of bytes required to encode val.a

encodedClass

public Class<T> encodedClass()

Description copied from interface: DataType

Inform consumers over what type this DataType operates. Useful when working with bare DataType instances.

Specified by:

encodedClass in interface DataType<T>

skip

public int skip(PositionedByteRange src)

Description copied from interface: DataType

Skip src's position forward over one encoded value.

Specified by:

skip in interface DataType<T>

Parameters:

src - the buffer containing the encoded value.

Returns:

number of bytes skipped.

decode

public T decode(PositionedByteRange src)

Description copied from interface: DataType

Read an instance of T from the buffer src.

Specified by:

decode in interface DataType<T>

Parameters:

src - the buffer containing the encoded value.

encode

public int encode(PositionedByteRange dst,
                  T val)

Description copied from interface: DataType

Write instance val into buffer dst.

Specified by:

encode in interface DataType<T>

Parameters:

dst - the buffer containing the encoded value.

val - the value to encode onto dst.

Returns:

number of bytes written.