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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 & Reducer tasks for
processing. It thus assumes the responsibility of processing record
boundaries and presenting the tasks with keys and values.
InputSplit,
InputFormat| Method Summary | |
|---|---|
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. |
| Method Detail |
|---|
boolean next(K key,
V value)
throws IOException
key - the key to read data intovalue - the value to read data into
IOExceptionK createKey()
V createValue()
long getPos()
throws IOException
IOException
void close()
throws IOException
InputSplit to future operations.
IOException
float getProgress()
throws IOException
RecordReader consumed i.e.
has been processed by?
0.0 to 1.0.
IOException
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