com.google.uzaygezen.core

Interface StreamingRollup<K,V extends AdditiveValue<V>>

Type Parameters:

K - key type

V - value type

All Known Implementing Classes:

BoundedRollup

public interface StreamingRollup<K,V extends AdditiveValue<V>>

Streaming aggregator that rolls up all the values into a tree.

Author:

Daniel Aioanei

Method Summary

Methods

Modifier and Type	Method and Description
void	feedRow(Iterator<K> leafPath, V value) The rows must come in nested groups.
MapNode<K,V>	finish() Returns the tree representing the rolled-up, aggregated data.

Method Detail

feedRow

void feedRow(Iterator<K> leafPath,
           V value)

The rows must come in nested groups. For instance sorting achieves that, but it is not necessary.

Parameters:

leafPath - identifies the location of the node onto which the value is added, starting from the root. An empty path represents the root itself. If the node doesn't exist, it will be created.

value -

finish

MapNode<K,V> finish()

Returns the tree representing the rolled-up, aggregated data. If there is no data then null is returned.