org.apache.hadoop.hive.ql.io.orc

Interface Reader

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.
java.lang.Iterable<java.lang.String>	getMetadataKeys() Get the user metadata keys.
java.nio.ByteBuffer	getMetadataValue(java.lang.String key) Get a user metadata value.
long	getNumberOfRows() Get the number of rows in the file.
ObjectInspector	getObjectInspector() Get the object inspector for looking at the objects.
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.
java.lang.Iterable<StripeInformation>	getStripes() Get the list of stripes.
java.util.List<org.apache.hadoop.hive.ql.io.orc.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) Deprecated.
RecordReader	rows(long offset, long length, boolean[] include, SearchArgument sarg, java.lang.String[] neededColumns) Create a RecordReader that will read a section of a file.

Method Detail

getNumberOfRows

long getNumberOfRows()

Get the number of rows in the file.

Returns:

the number of rows

getMetadataKeys

java.lang.Iterable<java.lang.String> getMetadataKeys()

Get the user metadata keys.

Returns:

the set of metadata keys

getMetadataValue

java.nio.ByteBuffer getMetadataValue(java.lang.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

java.lang.Iterable<StripeInformation> getStripes()

Get the list of stripes.

Returns:

the information about the stripes in order

getObjectInspector

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

java.util.List<org.apache.hadoop.hive.ql.io.orc.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 java.io.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:

java.io.IOException

rows

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

Deprecated.

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:

java.io.IOException

rows

RecordReader rows(long offset,
                  long length,
                  boolean[] include,
                  SearchArgument sarg,
                  java.lang.String[] neededColumns)
           throws java.io.IOException

Create a RecordReader that will read a section of a file. It starts reading at the first stripe after the offset and continues to the stripe that starts at offset + length. It also accepts a list of columns to read and a search argument.

Parameters:

offset - the minimum offset of the first stripe to read

length - the distance from offset of the first address to stop reading at

include - true for each column that should be included

sarg - a search argument that limits the rows that should be read.

neededColumns - the names of the included columns

Returns:

the record reader for the rows

Throws:

java.io.IOException