Package org.apache.drill.exec.store.excel

Class ExcelBatchReader

java.lang.Object

org.apache.drill.exec.store.excel.ExcelBatchReader

All Implemented Interfaces:

ManagedReader

public class ExcelBatchReader
extends Object
implements ManagedReader

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ExcelBatchReader.CellWriter
static class	ExcelBatchReader.IntCellWriter
static class	ExcelBatchReader.IntStringWriter
static class	ExcelBatchReader.NumericCellWriter
static class	ExcelBatchReader.NumericStringWriter
class	ExcelBatchReader.StringCellWriter
static class	ExcelBatchReader.TimestampCellWriter

Nested classes/interfaces inherited from interface org.apache.drill.exec.physical.impl.scan.v3.ManagedReader

ManagedReader.EarlyEofException

Constructor Summary

Constructors

Constructor	Description
ExcelBatchReader(org.apache.drill.exec.store.excel.ExcelBatchReader.ExcelReaderConfig readerConfig, EasySubScan scan, FileSchemaNegotiator negotiator)

Method Summary

Modifier and Type	Method	Description
void	close()	Release resources.
boolean	next()	Read the next batch.

Methods inherited from class java.lang.Object

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

Constructor Details

ExcelBatchReader

public ExcelBatchReader(org.apache.drill.exec.store.excel.ExcelBatchReader.ExcelReaderConfig readerConfig,
 EasySubScan scan,
 FileSchemaNegotiator negotiator)

Method Details

next

public boolean next()

Description copied from interface: ManagedReader

Read the next batch. Reading continues until either EOF, or until the mutator indicates that the batch is full. The batch is considered valid if it is non-empty. Returning true with an empty batch is valid, and is helpful on the very first batch (returning schema only.) An empty batch with a false return code indicates EOF and the batch will be discarded. A non-empty batch along with a false return result indicates a final, valid batch, but that EOF was reached and no more data is available.

This somewhat complex protocol avoids the need to allocate a final batch just to find out that no more data is available; it allows EOF to be returned along with the final batch.

Specified by:

next in interface ManagedReader

Returns:

true if more data may be available (and so next() should be called again, false to indicate that EOF was reached

close

public void close()

Description copied from interface: ManagedReader

Release resources. Called just after a failure, when the scanner is cancelled, or after next() returns EOF. Release all resources and close files. Guaranteed to be called if open() returns normally; will not be called if open() throws an exception.

Specified by:

close in interface ManagedReader