|
||||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | |||||||||
java.lang.Objectorg.apache.hadoop.mapreduce.RecordReader<LongWritable,T>
org.apache.hadoop.mapreduce.lib.db.DBRecordReader<T>
@InterfaceAudience.Public @InterfaceStability.Evolving public class DBRecordReader<T extends DBWritable>
A RecordReader that reads records from a SQL table. Emits LongWritables containing the record number as key and DBWritables as value.
| Field Summary | |
|---|---|
protected PreparedStatement |
statement
|
| Constructor Summary | |
|---|---|
DBRecordReader(DBInputFormat.DBInputSplit split,
Class<T> inputClass,
Configuration conf,
Connection conn,
DBConfiguration dbConfig,
String cond,
String[] fields,
String table)
|
|
| Method Summary | |
|---|---|
void |
close()
Close the record reader. |
T |
createValue()
Deprecated. |
protected ResultSet |
executeQuery(String query)
|
protected String |
getConditions()
|
protected Connection |
getConnection()
|
LongWritable |
getCurrentKey()
Get the current key |
T |
getCurrentValue()
Get the current value. |
protected DBConfiguration |
getDBConf()
|
protected String[] |
getFieldNames()
|
long |
getPos()
Deprecated. |
float |
getProgress()
The current progress of the record reader through its data. |
protected String |
getSelectQuery()
Returns the query for selecting the records, subclasses can override this for custom behaviour. |
protected DBInputFormat.DBInputSplit |
getSplit()
|
protected PreparedStatement |
getStatement()
|
protected String |
getTableName()
|
void |
initialize(InputSplit split,
TaskAttemptContext context)
Called once at initialization. |
boolean |
next(LongWritable key,
T value)
Deprecated. Use nextKeyValue() |
boolean |
nextKeyValue()
Read the next key, value pair. |
protected void |
setStatement(PreparedStatement stmt)
|
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
protected PreparedStatement statement
| Constructor Detail |
|---|
public DBRecordReader(DBInputFormat.DBInputSplit split,
Class<T> inputClass,
Configuration conf,
Connection conn,
DBConfiguration dbConfig,
String cond,
String[] fields,
String table)
throws SQLException
split - The InputSplit to read data for
SQLException| Method Detail |
|---|
protected ResultSet executeQuery(String query)
throws SQLException
SQLExceptionprotected String getSelectQuery()
public void close()
throws IOException
close in interface Closeableclose in class RecordReader<LongWritable,T extends DBWritable>IOException
public void initialize(InputSplit split,
TaskAttemptContext context)
throws IOException,
InterruptedException
RecordReader
initialize in class RecordReader<LongWritable,T extends DBWritable>split - the split that defines the range of records to readcontext - the information about the task
IOException
InterruptedExceptionpublic LongWritable getCurrentKey()
getCurrentKey in class RecordReader<LongWritable,T extends DBWritable>public T getCurrentValue()
getCurrentValue in class RecordReader<LongWritable,T extends DBWritable>@Deprecated public T createValue()
@Deprecated
public long getPos()
throws IOException
IOException
@Deprecated
public boolean next(LongWritable key,
T value)
throws IOException
nextKeyValue()
IOException
public float getProgress()
throws IOException
getProgress in class RecordReader<LongWritable,T extends DBWritable>IOException
public boolean nextKeyValue()
throws IOException
nextKeyValue in class RecordReader<LongWritable,T extends DBWritable>IOExceptionprotected DBInputFormat.DBInputSplit getSplit()
protected String[] getFieldNames()
protected String getTableName()
protected String getConditions()
protected DBConfiguration getDBConf()
protected Connection getConnection()
protected PreparedStatement getStatement()
protected void setStatement(PreparedStatement stmt)
|
||||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | |||||||||