org.apache.arrow.vector.file

Class ArrowReader<T extends ReadChannel>

java.lang.Object

org.apache.arrow.vector.file.ArrowReader<T>

All Implemented Interfaces:

AutoCloseable, DictionaryProvider

Direct Known Subclasses:

ArrowFileReader, ArrowStreamReader

public abstract class ArrowReader<T extends ReadChannel>
extends Object
implements DictionaryProvider, AutoCloseable

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.arrow.vector.dictionary.DictionaryProvider

DictionaryProvider.MapDictionaryProvider

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ArrowReader(T in, BufferAllocator allocator)

Method Summary

Modifier and Type	Method and Description
long	bytesRead()
void	close()
protected void	ensureInitialized()
Map<Long,Dictionary>	getDictionaryVectors() Returns any dictionaries
VectorSchemaRoot	getVectorSchemaRoot() Returns the vector schema root.
boolean	loadNextBatch()
Dictionary	lookup(long id)
protected abstract ArrowMessage	readMessage(T in, BufferAllocator allocator)
protected abstract Schema	readSchema(T in)

Methods inherited from class java.lang.Object

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

Constructor Detail

ArrowReader

protected ArrowReader(T in,
                      BufferAllocator allocator)

Method Detail

getVectorSchemaRoot

public VectorSchemaRoot getVectorSchemaRoot()
                                     throws IOException

Returns the vector schema root. This will be loaded with new values on every call to loadNextBatch

Returns:

the vector schema root

Throws:

IOException - if reading of schema fails

getDictionaryVectors

public Map<Long,Dictionary> getDictionaryVectors()
                                          throws IOException

Returns any dictionaries

Returns:

dictionaries, if any

Throws:

IOException - if reading of schema fails

lookup

public Dictionary lookup(long id)

Specified by:

lookup in interface DictionaryProvider

loadNextBatch

public boolean loadNextBatch()
                      throws IOException

Throws:

IOException

bytesRead

public long bytesRead()

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Throws:

IOException

readSchema

protected abstract Schema readSchema(T in)
                              throws IOException

Throws:

IOException

readMessage

protected abstract ArrowMessage readMessage(T in,
                                            BufferAllocator allocator)
                                     throws IOException

Throws:

IOException

ensureInitialized

protected void ensureInitialized()
                          throws IOException

Throws:

IOException