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java.lang.Objectorg.apache.hadoop.mapred.lib.db.DBInputFormat.DBRecordReader
protected class DBInputFormat.DBRecordReader
A RecordReader that reads records from a SQL table. Emits LongWritables containing the record number as key and DBWritables as value.
| Constructor Summary | |
|---|---|
protected |
DBInputFormat.DBRecordReader(DBInputFormat.DBInputSplit split,
Class<T> inputClass,
JobConf job)
|
| Method Summary | |
|---|---|
void |
close()
Close this InputSplit to future operations. |
LongWritable |
createKey()
Create an object of the appropriate type to be used as a key. |
T |
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. |
protected String |
getSelectQuery()
Returns the query for selecting the records, subclasses can override this for custom behaviour. |
boolean |
next(LongWritable key,
T value)
Reads the next key/value pair from the input for processing. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
|---|
protected DBInputFormat.DBRecordReader(DBInputFormat.DBInputSplit split,
Class<T> inputClass,
JobConf job)
throws SQLException
split - The InputSplit to read data for
SQLException| Method Detail |
|---|
protected String getSelectQuery()
public void close()
throws IOException
InputSplit to future operations.
close in interface RecordReader<LongWritable,T extends DBWritable>IOExceptionpublic LongWritable createKey()
createKey in interface RecordReader<LongWritable,T extends DBWritable>public T createValue()
createValue in interface RecordReader<LongWritable,T extends DBWritable>
public long getPos()
throws IOException
getPos in interface RecordReader<LongWritable,T extends DBWritable>IOException
public float getProgress()
throws IOException
RecordReader consumed i.e.
has been processed by?
getProgress in interface RecordReader<LongWritable,T extends DBWritable>0.0 to 1.0.
IOException
public boolean next(LongWritable key,
T value)
throws IOException
next in interface RecordReader<LongWritable,T extends DBWritable>key - the key to read data intovalue - the value to read data into
IOException
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