com.facebook.hive.orc

Interface Reader

All Known Implementing Classes:

ReaderImpl

public interface Reader

The interface for reading ORC files. One Reader can support multiple concurrent RecordReader.

Method Summary

Modifier and Type	Method and Description
CompressionKind	getCompression() Get the compression kind.
int	getCompressionSize() Get the buffer size for the compression.
long	getContentLength() Get the length of the file.
Iterable<String>	getMetadataKeys() Get the user metadata keys.
ByteBuffer	getMetadataValue(String key) Get a user metadata value.
long	getNumberOfRows() Get the number of rows in the file.
org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector	getObjectInspector() Get the object inspector for looking at the objects.
long	getRawDataSize() Get the raw size of the data in the file
int	getRowIndexStride() Get the number of rows per a entry in the row index.
ColumnStatistics[]	getStatistics() Get the statistics about the columns in the file.
Iterable<StripeInformation>	getStripes() Get the list of stripes.
List<OrcProto.Type>	getTypes() Get the list of types contained in the file.
RecordReader	rows(boolean[] include) Create a RecordReader that will scan the entire file.
RecordReader	rows(long offset, long length, boolean[] include) Create a RecordReader that will start reading at the first stripe after offset up to the stripe that starts at offset + length.
StripeReader	stripes(long offset, long length) Create a StripeReader that will start reading at the first stripe after offset up to the stripe that starts at offset + length.

Method Detail

getNumberOfRows

long getNumberOfRows()

Get the number of rows in the file.

Returns:

the number of rows

getRawDataSize

long getRawDataSize()

Get the raw size of the data in the file

Returns:

the raw size

getMetadataKeys

Iterable<String> getMetadataKeys()

Get the user metadata keys.

Returns:

the set of metadata keys

getMetadataValue

ByteBuffer getMetadataValue(String key)

Get a user metadata value.

Parameters:

key - a key given by the user

Returns:

the bytes associated with the given key

getCompression

CompressionKind getCompression()

Get the compression kind.

Returns:

the kind of compression in the file

getCompressionSize

int getCompressionSize()

Get the buffer size for the compression.

Returns:

number of bytes to buffer for the compression codec.

getRowIndexStride

int getRowIndexStride()

Get the number of rows per a entry in the row index.

Returns:

the number of rows per an entry in the row index or 0 if there is no row index.

getStripes

Iterable<StripeInformation> getStripes()

Get the list of stripes.

Returns:

the information about the stripes in order

getObjectInspector

org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector getObjectInspector()

Get the object inspector for looking at the objects.

Returns:

an object inspector for each row returned

getContentLength

long getContentLength()

Get the length of the file.

Returns:

the number of bytes in the file

getStatistics

ColumnStatistics[] getStatistics()

Get the statistics about the columns in the file.

Returns:

the information about the column

getTypes

List<OrcProto.Type> getTypes()

Get the list of types contained in the file. The root type is the first type in the list.

Returns:

the list of flattened types

rows

RecordReader rows(boolean[] include)
           throws IOException

Create a RecordReader that will scan the entire file.

Parameters:

include - true for each column that should be included

Returns:

A new RecordReader

Throws:

IOException

rows

RecordReader rows(long offset,
                  long length,
                  boolean[] include)
           throws IOException

Create a RecordReader that will start reading at the first stripe after offset up to the stripe that starts at offset + length. This is intended to work with MapReduce's FileInputFormat where divisions are picked blindly, but they must cover all of the rows.

Parameters:

offset - a byte offset in the file

length - a number of bytes in the file

include - true for each column that should be included

Returns:

a new RecordReader that will read the specified rows.

Throws:

IOException

stripes

StripeReader stripes(long offset,
                     long length)
              throws IOException

Create a StripeReader that will start reading at the first stripe after offset up to the stripe that starts at offset + length.

Parameters:

offset - a byte offset in the file

length - a number of bytes in the file

Returns:

a new StripeReader that will read the specified stripes.

Throws:

IOException