Class ColumnarContext

java.lang.Object

io.krabka.streams.columnar.ColumnarContext

public final class ColumnarContext
extends Object

Collects batches that a columnar processor forwards.

A fresh context is handed to ColumnarProcessor.process(ColumnarContext, VectorSchemaRoot) for every input batch. Calling forward(VectorSchemaRoot) zero times drops the batch, once passes one batch downstream, and several times fans the input out into several downstream batches, delivered in forwarding order.

Example

ColumnarProcessor splitBySize = (context, batch) -> {
    context.forward(smallRows(batch));
    context.forward(largeRows(batch));
};

Constructor Summary

Constructors

Constructor	Description
ColumnarContext()	Creates an empty context.

Method Summary

Modifier and Type	Method	Description
void	forward(org.apache.arrow.vector.VectorSchemaRoot batch)	Forwards one batch to every downstream node.

Methods inherited from class Object

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

Constructor Details

ColumnarContext

public ColumnarContext()

Creates an empty context.

The framework creates one per processed batch; create one directly only to unit-test a ColumnarProcessor outside a topology.

Method Details

forward

public void forward(org.apache.arrow.vector.VectorSchemaRoot batch)

Forwards one batch to every downstream node.

Ownership of a forwarded batch transfers to the framework, which closes it once downstream processing finishes. Forwarding the input batch itself is allowed.

Parameters:

batch - the batch to pass downstream

Throws:

NullPointerException - if batch is null