@InterfaceAudience.Public
@InterfaceStability.Stable
public interface RecordReader<K,V>
RecordReader reads <key, value> pairs from an
InputSplit.
RecordReader, typically, converts the byte-oriented view of
the input, provided by the InputSplit, and presents a
record-oriented view for the Mapper and Reducer tasks for
processing. It thus assumes the responsibility of processing record
boundaries and presenting the tasks with keys and values.
InputSplit,
InputFormat| Modifier and Type | Method and Description |
|---|---|
void |
close()
Close this
InputSplit to future operations. |
K |
createKey()
Create an object of the appropriate type to be used as a key.
|
V |
createValue()
Create an object of the appropriate type to be used as a value.
|
long |
getPos()
Returns the current position in the input.
|
float |
getProgress()
How much of the input has the
RecordReader consumed i.e. |
boolean |
next(K key,
V value)
Reads the next key/value pair from the input for processing.
|
boolean next(K key, V value) throws IOException
key - the key to read data intovalue - the value to read data intoIOExceptionK createKey()
V createValue()
long getPos()
throws IOException
IOExceptionvoid close()
throws IOException
InputSplit to future operations.IOExceptionfloat getProgress()
throws IOException
RecordReader consumed i.e.
has been processed by?0.0 to 1.0.IOExceptionCopyright © 2022 Apache Software Foundation. All rights reserved.