org.apache.hive.hcatalog.data

Class HCatRecordSerDe

java.lang.Object

org.apache.hive.hcatalog.data.HCatRecordSerDe

All Implemented Interfaces:

Deserializer, SerDe, Serializer

public class HCatRecordSerDe
extends Object
implements SerDe

SerDe class for serializing to and from HCatRecord

Constructor Summary

Constructors

Constructor and Description
HCatRecordSerDe()

Method Summary

Methods

Modifier and Type	Method and Description
Object	deserialize(org.apache.hadoop.io.Writable data) The purpose of a deserialize method is to turn a data blob which is a writable representation of the data into an object that can then be parsed using the appropriate ObjectInspector.
ObjectInspector	getObjectInspector() Return an object inspector that can read through the object that we return 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.
void	initialize(HCatSchema hsch)
org.apache.hadoop.io.Writable	serialize(Object obj, ObjectInspector objInspector) The purpose of the serialize method is to turn an object-representation with a provided ObjectInspector into a Writable format, which the underlying layer can then use to write out.
static Object	serializeField(Object field, ObjectInspector fieldObjectInspector) Return underlying Java Object from an object-representation that is readable by a provided ObjectInspector.

Methods inherited from class java.lang.Object

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

Constructor Detail

HCatRecordSerDe

public HCatRecordSerDe()
                throws SerDeException

Throws:

SerDeException

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

initialize

public void initialize(HCatSchema hsch)
                throws SerDeException

Throws:

SerDeException

deserialize

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

The purpose of a deserialize method is to turn a data blob which is a writable representation of the data into an object that can then be parsed using the appropriate ObjectInspector. In this case, since HCatRecord is directly already the Writable object, there's no extra work to be done here. Most of the logic resides in the ObjectInspector to be able to return values from within the HCatRecord to hive when it wants it.

Specified by:

deserialize in interface Deserializer

Parameters:

data - 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

The purpose of the serialize method is to turn an object-representation with a provided ObjectInspector into a Writable format, which the underlying layer can then use to write out. In this case, it means that Hive will call this method to convert an object with appropriate objectinspectors that it knows about, to write out a HCatRecord.

Specified by:

serialize in interface Serializer

Throws:

SerDeException

serializeField

public static Object serializeField(Object field,
                    ObjectInspector fieldObjectInspector)
                             throws SerDeException

Return underlying Java Object from an object-representation that is readable by a provided ObjectInspector.

Throws:

SerDeException

getObjectInspector

public ObjectInspector getObjectInspector()
                                   throws SerDeException

Return an object inspector that can read through the object that we return from deserialize(). To wit, that means we need to return an ObjectInspector that can read HCatRecord, given the type info for it during initialize(). This also means that this method cannot and should not be called before initialize()

Specified by:

getObjectInspector in interface Deserializer

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

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