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

Interface ReaderFactory<T extends SchemaNegotiator>

All Known Implementing Classes:
FileReaderFactory, ScanLifecycleBuilder.DummyReaderFactory, ShpFormatPlugin.ShpReaderFactory, XMLFormatPlugin.XMLReaderFactory
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
    Description
    boolean
    hasNext()
     
    ManagedReader
    next(T negotiator)