org.apache.drill.exec.physical.impl.scan.v3

Interface ReaderFactory<T extends SchemaNegotiator>

All Known Implementing Classes:

FileReaderFactory, ScanLifecycleBuilder.DummyReaderFactory

public interface ReaderFactory<T extends SchemaNegotiator>

Creates a batch reader on demand. Unlike earlier versions of Drill, this framework creates readers one by one, when they are needed. Doing so avoids excessive resource demands that come from creating potentially thousands of readers up front.

The reader itself is unique to each file type. This interface provides a common interface that this framework can use to create the file-specific reader on demand.

Also manages opening the reader using a scan-specific schema negotiator.

Method Summary

Modifier and Type	Method and Description
boolean	hasNext()
ManagedReader	next(T negotiator)

Method Detail

hasNext

boolean hasNext()

next

ManagedReader next(T negotiator)
            throws ManagedReader.EarlyEofException

Throws:

ManagedReader.EarlyEofException