Module org.apache.arrow.dataset

Package org.apache.arrow.dataset.jni

Class NativeDatasetFactory

java.lang.Object

org.apache.arrow.dataset.jni.NativeDatasetFactory

All Implemented Interfaces:

AutoCloseable, DatasetFactory

Direct Known Subclasses:

FileSystemDatasetFactory

public class NativeDatasetFactory
extends Object
implements DatasetFactory

Native implementation of DatasetFactory.

Constructor Summary

Constructors

Constructor	Description
NativeDatasetFactory(BufferAllocator allocator, NativeMemoryPool memoryPool, long datasetFactoryId)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	close()	Close this factory by release the pointer of the native instance.
NativeDataset	finish()	Create a Dataset with auto-inferred schema.
NativeDataset	finish(Schema schema)	Create a Dataset with predefined schema.
Schema	inspect()	Get unified schema for the resulting Dataset.

Methods inherited from class java.lang.Object

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

Constructor Details

NativeDatasetFactory

public NativeDatasetFactory(BufferAllocator allocator,
 NativeMemoryPool memoryPool,
 long datasetFactoryId)

Constructor.

Parameters:

allocator - a context allocator associated with this factory. Any buffer that will be created natively will be then bound to this allocator.

memoryPool - the native memory pool associated with this factory. Any buffer created natively should request for memory spaces from this memory pool. This is a mapped instance of c++ arrow::MemoryPool.

datasetFactoryId - an ID, at the same time the native pointer of the underlying native instance of this factory. Make sure in c++ side the pointer is pointing to the shared pointer wrapping the actual instance so we could successfully decrease the reference count once close() is called.

See Also:

• close()

Method Details

inspect

public Schema inspect()

Description copied from interface: DatasetFactory

Get unified schema for the resulting Dataset.

Specified by:

inspect in interface DatasetFactory

Returns:

the schema object inspected

finish

public NativeDataset finish()

Description copied from interface: DatasetFactory

Create a Dataset with auto-inferred schema. Which means, the schema of the resulting Dataset will be the same with calling DatasetFactory.inspect() manually.

Specified by:

finish in interface DatasetFactory

Returns:

the Dataset instance

finish

public NativeDataset finish(Schema schema)

Description copied from interface: DatasetFactory

Create a Dataset with predefined schema. Schema inference will not be performed.

Specified by:

finish in interface DatasetFactory

Parameters:

schema - a predefined schema

Returns:

the Dataset instance

close

public void close()

Close this factory by release the pointer of the native instance.

Specified by:

close in interface AutoCloseable