org.apache.hadoop.hive.serde2.binarysortable
Class BinarySortableSerDe

java.lang.Object
  org.apache.hadoop.hive.serde2.binarysortable.BinarySortableSerDe

All Implemented Interfaces:

Deserializer, SerDe, Serializer

public class BinarySortableSerDe
extends Object
implements SerDe

BinarySortableSerDe can be used to write data in a way that the data can be compared byte-by-byte with the same order. The data format: NULL: a single byte \0 NON-NULL Primitives: ALWAYS prepend a single byte \1, and then: Boolean: FALSE = \1, TRUE = \2 Byte: flip the sign-bit to make sure negative comes before positive Short: flip the sign-bit to make sure negative comes before positive Int: flip the sign-bit to make sure negative comes before positive Long: flip the sign-bit to make sure negative comes before positive Double: flip the sign-bit for positive double, and all bits for negative double values String: NULL-terminated UTF-8 string, with NULL escaped to \1 \1, and \1 escaped to \1 \2 NON-NULL Complex Types: ALWAYS prepend a single byte \1, and then: Struct: one field by one field. List: \1 followed by each element, and \0 to terminate Map: \1 followed by each key and then each value, and \0 to terminate This SerDe takes an additional parameter SERIALIZATION_SORT_ORDER which is a string containing only "+" and "-". The length of the string should equal to the number of fields in the top-level struct for serialization. "+" means the field should be sorted ascendingly, and "-" means descendingly. The sub fields in the same top-level field will have the same sort order.

Field Summary

static org.apache.commons.logging.Log

LOG

Constructor Summary

BinarySortableSerDe()

Method Summary

Object	deserialize(org.apache.hadoop.io.Writable blob) Deserialize an object out of a Writable blob.
ObjectInspector	getObjectInspector() Get the object inspector that can be used to navigate through the internal structure of the Object returned from deserialize(...).
SerDeStats	getSerDeStats() Returns statistics collected when serializing
Class<? extends org.apache.hadoop.io.Writable>	getSerializedClass() Returns the Writable class that would be returned by the serialize method.
void	initialize(org.apache.hadoop.conf.Configuration conf, Properties tbl) Initialize the HiveDeserializer.
org.apache.hadoop.io.Writable	serialize(Object obj, ObjectInspector objInspector) Serialize an object by navigating inside the Object with the ObjectInspector.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.apache.commons.logging.Log LOG

Constructor Detail

BinarySortableSerDe

public BinarySortableSerDe()

Method Detail

initialize

public void initialize(org.apache.hadoop.conf.Configuration conf,
                       Properties tbl)
                throws SerDeException

Description copied from interface: Deserializer

Initialize the HiveDeserializer.

Specified by:

initialize in interface Deserializer

Specified by:

initialize in interface Serializer

Parameters:

conf - System properties

tbl - table properties

Throws:

SerDeException

getSerializedClass

public Class<? extends org.apache.hadoop.io.Writable> getSerializedClass()

Description copied from interface: Serializer

Returns the Writable class that would be returned by the serialize method. This is used to initialize SequenceFile header.

Specified by:

getSerializedClass in interface Serializer

getObjectInspector

public ObjectInspector getObjectInspector()
                                   throws SerDeException

Description copied from interface: Deserializer

Get the object inspector that can be used to navigate through the internal structure of the Object returned from deserialize(...).

Specified by:

getObjectInspector in interface Deserializer

Throws:

SerDeException

deserialize

public Object deserialize(org.apache.hadoop.io.Writable blob)
                   throws SerDeException

Description copied from interface: Deserializer

Deserialize an object out of a Writable blob. In most cases, the return value of this function will be constant since the function will reuse the returned object. If the client wants to keep a copy of the object, the client needs to clone the returned value by calling ObjectInspectorUtils.getStandardObject().

Specified by:

deserialize in interface Deserializer

Parameters:

blob - The Writable object containing a serialized object

Returns:

A Java object representing the contents in the blob.

Throws:

SerDeException

serialize

public org.apache.hadoop.io.Writable serialize(Object obj,
                                               ObjectInspector objInspector)
                                        throws SerDeException

Description copied from interface: Serializer

Serialize an object by navigating inside the Object with the ObjectInspector. In most cases, the return value of this function will be constant since the function will reuse the Writable object. If the client wants to keep a copy of the Writable, the client needs to clone the returned value.

Specified by:

serialize in interface Serializer

Throws:

SerDeException

getSerDeStats

public SerDeStats getSerDeStats()

Description copied from interface: Deserializer

Returns statistics collected when serializing

Specified by:

getSerDeStats in interface Deserializer

Specified by:

getSerDeStats in interface Serializer