Package org.apache.hadoop.mapreduce.lib.join

Class WrappedRecordReader<K extends WritableComparable<?>,U extends Writable>

java.lang.Object
org.apache.hadoop.mapreduce.RecordReader<K,V>
org.apache.hadoop.mapreduce.lib.join.ComposableRecordReader<K,U>
org.apache.hadoop.mapreduce.lib.join.WrappedRecordReader<K,U>
All Implemented Interfaces:
Closeable, AutoCloseable, Comparable<ComposableRecordReader<K,?>>
@Public @Stable public class WrappedRecordReader<K extends WritableComparable<?>,U extends Writable> extends ComposableRecordReader<K,U>
Proxy class for a RecordReader participating in the join framework. This class keeps track of the "head" key-value pair for the provided RecordReader and keeps a store of values matching a key when this source is participating in a join.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected WritableComparator
    cmp
     
    protected boolean
    empty
     

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    WrappedRecordReader(int id)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    accept(org.apache.hadoop.mapreduce.lib.join.CompositeRecordReader.JoinCollector i, K key)
    Add an iterator to the collector at the position occupied by this RecordReader over the values in this stream paired with the key provided (ie register a stream of values from this source matching K with a collector).
    void
    close()
    Forward close request to proxied RR.
    int
    compareTo(ComposableRecordReader<K,?> other)
    Implement Comparable contract (compare key at head of proxied RR with that of another).
    K
    createKey()
    Request new key from proxied RR.
    U
    createValue()
     
    boolean
    equals(Object other)
    Return true iff compareTo(other) retn true.
    K
    getCurrentKey()
    Get current key
    U
    getCurrentValue()
    Get current value
    float
    getProgress()
    Request progress from proxied RR.
    int
    hashCode()
     
    boolean
    hasNext()
    Return true if the RR- including the k,v pair stored in this object- is exhausted.
    int
    id()
    void
    initialize(InputSplit split, TaskAttemptContext context)
    Called once at initialization.
    K
    key()
    Return the key at the head of this RR.
    void
    key(K qkey)
    Clone the key at the head of this RR into the object supplied.
    boolean
    nextKeyValue()
    Read the next k,v pair into the head of this object; return true iff the RR and this are exhausted.
    void
    skip(K key)
    Skip key-value pairs with keys less than or equal to the key provided.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait