org.apache.hadoop.mapred.join

接口 ComposableRecordReader<K extends WritableComparable,V extends Writable>

所有超级接口:

Comparable<ComposableRecordReader<K,?>>, RecordReader<K,V>

所有已知实现类:

InnerJoinRecordReader, JoinRecordReader, MultiFilterRecordReader, OuterJoinRecordReader, OverrideRecordReader, WrappedRecordReader

public interface ComposableRecordReader<K extends WritableComparable,V extends Writable>
extends RecordReader<K,V>, Comparable<ComposableRecordReader<K,?>>

Additional operations required of a RecordReader to participate in a join.

方法概要

方法

限定符和类型	方法和说明
void	accept(org.apache.hadoop.mapred.join.CompositeRecordReader.JoinCollector jc, K key) While key-value pairs from this RecordReader match the given key, register them with the JoinCollector provided.
boolean	hasNext() Returns true if the stream is not empty, but provides no guarantee that a call to next(K,V) will succeed.
int	id() Return the position in the collector this class occupies.
K	key() Return the key this RecordReader would supply on a call to next(K,V)
void	key(K key) Clone the key at the head of this RecordReader into the object provided.
void	skip(K key) Skip key-value pairs with keys less than or equal to the key provided.

从接口继承的方法 org.apache.hadoop.mapred.RecordReader

close, createKey, createValue, getPos, getProgress, next

从接口继承的方法 java.lang.Comparable

compareTo

方法详细资料

id

int id()

Return the position in the collector this class occupies.

key

K key()

Return the key this RecordReader would supply on a call to next(K,V)

key

void key(K key)
         throws IOException

Clone the key at the head of this RecordReader into the object provided.

抛出:

IOException

hasNext

boolean hasNext()

Returns true if the stream is not empty, but provides no guarantee that a call to next(K,V) will succeed.

skip

void skip(K key)
          throws IOException

Skip key-value pairs with keys less than or equal to the key provided.

抛出:

IOException

accept

void accept(org.apache.hadoop.mapred.join.CompositeRecordReader.JoinCollector jc,
          K key)
            throws IOException

While key-value pairs from this RecordReader match the given key, register them with the JoinCollector provided.

抛出:

IOException