org.apache.pig.data

Class SchemaTupleFactory

java.lang.Object

org.apache.pig.data.SchemaTupleFactory

All Implemented Interfaces:

TupleMaker<SchemaTuple<?>>

public class SchemaTupleFactory
extends Object
implements TupleMaker<SchemaTuple<?>>

This is an implementation of TupleFactory that will instantiate SchemaTuple's. This class has nothing to do with the actual generation of code, and instead simply encapsulates the classes which allow for efficiently creating SchemaTuples.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SchemaTupleFactory(Class<SchemaTuple<?>> clazz, SchemaTuple.SchemaTupleQuickGenerator<? extends SchemaTuple<?>> generator)

Method Summary

Modifier and Type	Method and Description
protected static SchemaTupleFactory	getInstance(int id) This method is the publicly facing method which returns a SchemaTupleFactory which will generate the SchemaTuple associated with the given identifier.
static SchemaTupleFactory	getInstance(Schema s)
static SchemaTupleFactory	getInstance(Schema s, boolean isAppendable)
static SchemaTupleFactory	getInstance(Schema s, boolean isAppendable, SchemaTupleClassGenerator.GenContext context) This method is the publicly facing method which returns a SchemaTupleFactory which will generate SchemaTuples of the given Schema.
boolean	isFixedSize()
static boolean	isGeneratable(Schema s) This method inspects a Schema to see whether or not a SchemaTuple implementation can be generated for the types present.
SchemaTuple<?>	newTuple()
SchemaTuple<?>	newTuple(int size)
Class<SchemaTuple<?>>	tupleClass()

Methods inherited from class java.lang.Object

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

Constructor Detail

SchemaTupleFactory

protected SchemaTupleFactory(Class<SchemaTuple<?>> clazz,
                             SchemaTuple.SchemaTupleQuickGenerator<? extends SchemaTuple<?>> generator)

Method Detail

isGeneratable

public static boolean isGeneratable(Schema s)

This method inspects a Schema to see whether or not a SchemaTuple implementation can be generated for the types present. Currently, bags and maps are not supported.

Parameters:

s - as Schema

Returns:

boolean type value, true if it is generatable

newTuple

public SchemaTuple<?> newTuple()

Specified by:

newTuple in interface TupleMaker<SchemaTuple<?>>

newTuple

public SchemaTuple<?> newTuple(int size)

Specified by:

newTuple in interface TupleMaker<SchemaTuple<?>>

tupleClass

public Class<SchemaTuple<?>> tupleClass()

isFixedSize

public boolean isFixedSize()

getInstance

protected static SchemaTupleFactory getInstance(int id)

This method is the publicly facing method which returns a SchemaTupleFactory which will generate the SchemaTuple associated with the given identifier. This method is primarily for internal use in cases where the problem SchemaTuple is known based on the identifier associated with it (such as when deserializing).

Parameters:

id - as int, means identifier

Returns:

SchemaTupleFactory which will return SchemaTuple's of the given identifier

getInstance

public static SchemaTupleFactory getInstance(Schema s,
                                             boolean isAppendable,
                                             SchemaTupleClassGenerator.GenContext context)

This method is the publicly facing method which returns a SchemaTupleFactory which will generate SchemaTuples of the given Schema. Note that this method returns null if such a given SchemaTupleFactory does not exist, instead of throwing an error. The GenContext is used to specify the context in which we are requesting a SchemaTupleFactory. This is necessary so that the use of SchemaTuple can be controlled -- it is possible that someone wants a factory that generates code in the context of joins, but wants to disable such use for udfs.

Parameters:

s - the Schema generated

isAppendable - whether or not the SchemaTuple should be appendable

context - the context in which we want a SchemaTupleFactory

Returns:

SchemaTupleFactory which will return SchemaTuple's of the desired Schema

getInstance

public static SchemaTupleFactory getInstance(Schema s,
                                             boolean isAppendable)

getInstance

public static SchemaTupleFactory getInstance(Schema s)