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java.lang.Objectorg.apache.hadoop.mapred.join.CompositeRecordReader<K,V,V>
org.apache.hadoop.mapred.join.MultiFilterRecordReader<K,V>
org.apache.hadoop.mapred.join.OverrideRecordReader<K,V>
public class OverrideRecordReader<K extends WritableComparable,V extends Writable>
Prefer the "rightmost" data source for this key. For example, override(S1,S2,S3) will prefer values from S3 over S2, and values from S2 over S1 for all keys emitted from all sources.
Nested Class Summary |
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Nested classes/interfaces inherited from class org.apache.hadoop.mapred.join.MultiFilterRecordReader |
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MultiFilterRecordReader.MultiFilterDelegationIterator |
Field Summary |
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Fields inherited from class org.apache.hadoop.mapred.join.CompositeRecordReader |
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jc, kids |
Method Summary | |
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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. |
protected V |
emit(TupleWritable dst)
Emit the value with the highest position in the tuple. |
protected void |
fillJoinCollector(K iterkey)
Instead of filling the JoinCollector with iterators from all data sources, fill only the rightmost for this key. |
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. |
Methods inherited from class org.apache.hadoop.mapred.join.MultiFilterRecordReader |
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combine, createValue, getDelegate, next |
Methods inherited from class org.apache.hadoop.mapred.join.CompositeRecordReader |
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accept, add, close, compareTo, createInternalValue, createKey, getComparator, getConf, getPos, getProgress, getRecordReaderQueue, hasNext, id, key, key, setConf, skip |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface org.apache.hadoop.mapred.RecordReader |
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close, createKey, getPos, getProgress |
Methods inherited from interface java.lang.Comparable |
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compareTo |
Method Detail |
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protected V emit(TupleWritable dst)
emit
in class MultiFilterRecordReader<K extends WritableComparable,V extends Writable>
protected void fillJoinCollector(K iterkey) throws IOException
fillJoinCollector
in class CompositeRecordReader<K extends WritableComparable,V extends Writable,V extends Writable>
IOException
public int id()
public K key()
public void key(K key) throws IOException
IOException
public boolean hasNext()
public void skip(K key) throws IOException
IOException
public void accept(org.apache.hadoop.mapred.join.CompositeRecordReader.JoinCollector jc, K key) throws IOException
IOException
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