org.apache.hadoop.hive.serde2.lazy

Class LazySimpleSerDe

java.lang.Object

org.apache.hadoop.hive.serde2.AbstractSerDe

org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe

All Implemented Interfaces:

Deserializer, SerDe, Serializer

Direct Known Subclasses:

DelimitedJSONSerDe

public class LazySimpleSerDe
extends AbstractSerDe

LazySimpleSerDe can be used to read the same data format as MetadataTypedColumnsetSerDe and TCTLSeparatedProtocol. However, LazySimpleSerDe creates Objects in a lazy way, to provide better performance. Also LazySimpleSerDe outputs typed columns instead of treating all columns as String like MetadataTypedColumnsetSerDe.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LazySimpleSerDe.SerDeParameters SerDeParameters.

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	DefaultSeparators
static org.apache.commons.logging.Log	LOG
static java.lang.String	SERIALIZATION_EXTEND_NESTING_LEVELS

Constructor Summary

Constructors

Constructor and Description
LazySimpleSerDe()

Method Summary

Modifier and Type	Method and Description
java.lang.Object	deserialize(Writable field) Deserialize a row from the Writable to a LazyObject.
static byte	getByte(java.lang.String altValue, byte defaultVal) Return the byte value of the number string.
ObjectInspector	getObjectInspector() Returns the ObjectInspector for the row.
SerDeStats	getSerDeStats() Returns the statistics after (de)serialization)
java.lang.Class<? extends Writable>	getSerializedClass() Returns the Writable Class after serialization.
void	initialize(Configuration job, java.util.Properties tbl) Initialize the SerDe given the parameters.
static LazySimpleSerDe.SerDeParameters	initSerdeParams(Configuration job, java.util.Properties tbl, java.lang.String serdeName)
static void	serialize(ByteStream.Output out, java.lang.Object obj, ObjectInspector objInspector, byte[] separators, int level, Text nullSequence, boolean escaped, byte escapeChar, boolean[] needsEscape) Serialize the row into the StringBuilder.
Writable	serialize(java.lang.Object obj, ObjectInspector objInspector) Serialize a row of data.
protected void	serializeField(ByteStream.Output out, java.lang.Object obj, ObjectInspector objInspector, LazySimpleSerDe.SerDeParameters serdeParams)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

LOG

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

SERIALIZATION_EXTEND_NESTING_LEVELS

public static final java.lang.String SERIALIZATION_EXTEND_NESTING_LEVELS

See Also:

Constant Field Values

DefaultSeparators

public static final byte[] DefaultSeparators

Constructor Detail

LazySimpleSerDe

public LazySimpleSerDe()
                throws SerDeException

Throws:

SerDeException

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getByte

public static byte getByte(java.lang.String altValue,
                           byte defaultVal)

Return the byte value of the number string.

Parameters:

altValue - The string containing a number.

defaultVal - If the altValue does not represent a number, return the defaultVal.

initialize

public void initialize(Configuration job,
                       java.util.Properties tbl)
                throws SerDeException

Initialize the SerDe given the parameters. serialization.format: separator char or byte code (only supports byte-value up to 127) columns: ","-separated column names columns.types: ",", ":", or ";"-separated column types

Specified by:

initialize in interface Deserializer

Specified by:

initialize in interface Serializer

Specified by:

initialize in class AbstractSerDe

Parameters:

job - System properties

tbl - table properties

Throws:

SerDeException

See Also:

Deserializer.initialize(Configuration, Properties)

initSerdeParams

public static LazySimpleSerDe.SerDeParameters initSerdeParams(Configuration job,
                                                              java.util.Properties tbl,
                                                              java.lang.String serdeName)
                                                       throws SerDeException

Throws:

SerDeException

deserialize

public java.lang.Object deserialize(Writable field)
                             throws SerDeException

Deserialize a row from the Writable to a LazyObject.

Specified by:

deserialize in interface Deserializer

Specified by:

deserialize in class AbstractSerDe

Parameters:

field - the Writable that contains the data

Returns:

The deserialized row Object.

Throws:

SerDeException

See Also:

Deserializer.deserialize(Writable)

getObjectInspector

public ObjectInspector getObjectInspector()
                                   throws SerDeException

Returns the ObjectInspector for the row.

Specified by:

getObjectInspector in interface Deserializer

Specified by:

getObjectInspector in class AbstractSerDe

Throws:

SerDeException

getSerializedClass

public java.lang.Class<? extends Writable> getSerializedClass()

Returns the Writable Class after serialization.

Specified by:

getSerializedClass in interface Serializer

Specified by:

getSerializedClass in class AbstractSerDe

See Also:

Serializer.getSerializedClass()

serialize

public Writable serialize(java.lang.Object obj,
                          ObjectInspector objInspector)
                   throws SerDeException

Serialize a row of data.

Specified by:

serialize in interface Serializer

Specified by:

serialize in class AbstractSerDe

Parameters:

obj - The row object

objInspector - The ObjectInspector for the row object

Returns:

The serialized Writable object

Throws:

java.io.IOException

SerDeException

See Also:

Serializer.serialize(Object, ObjectInspector)

serializeField

protected void serializeField(ByteStream.Output out,
                              java.lang.Object obj,
                              ObjectInspector objInspector,
                              LazySimpleSerDe.SerDeParameters serdeParams)
                       throws SerDeException

Throws:

SerDeException

serialize

public static void serialize(ByteStream.Output out,
                             java.lang.Object obj,
                             ObjectInspector objInspector,
                             byte[] separators,
                             int level,
                             Text nullSequence,
                             boolean escaped,
                             byte escapeChar,
                             boolean[] needsEscape)
                      throws java.io.IOException,
                             SerDeException

Serialize the row into the StringBuilder.

Parameters:

out - The StringBuilder to store the serialized data.

obj - The object for the current field.

objInspector - The ObjectInspector for the current Object.

separators - The separators array.

level - The current level of separator.

nullSequence - The byte sequence representing the NULL value.

escaped - Whether we need to escape the data when writing out

escapeChar - Which char to use as the escape char, e.g. '\\'

needsEscape - Which chars needs to be escaped. This array should have size of 128. Negative byte values (or byte values >= 128) are never escaped.

Throws:

java.io.IOException

SerDeException

getSerDeStats

public SerDeStats getSerDeStats()

Returns the statistics after (de)serialization)

Specified by:

getSerDeStats in interface Deserializer

Specified by:

getSerDeStats in interface Serializer

Specified by:

getSerDeStats in class AbstractSerDe