org.apache.kudu.client

Class KuduScanner

java.lang.Object

org.apache.kudu.client.KuduScanner

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public class KuduScanner
extends Object

Synchronous version of AsyncKuduScanner. Offers the same API but with blocking methods.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	KuduScanner.KuduScannerBuilder A Builder class to build KuduScanner.

Method Summary

Modifier and Type	Method and Description
RowResultIterator	close() Closes this scanner (don't forget to call this when you're done with it!).
long	getBatchSizeBytes() Returns the maximum number of bytes returned by the scanner, on each batch.
boolean	getCacheBlocks() Returns if this scanner was configured to cache data blocks or not.
long	getLimit() Returns the maximum number of rows that this scanner was configured to return.
Schema	getProjectionSchema() Returns the projection schema of this scanner.
AsyncKuduScanner.ReadMode	getReadMode() Returns the ReadMode for this scanner.
boolean	hasMoreRows() Tells if the last rpc returned that there might be more rows to scan.
RowResultIterator	nextRows() Scans a number of rows.

Methods inherited from class java.lang.Object

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

Method Detail

hasMoreRows

public boolean hasMoreRows()

Tells if the last rpc returned that there might be more rows to scan.

Returns:

true if there might be more data to scan, else false

nextRows

public RowResultIterator nextRows()
                           throws KuduException

Scans a number of rows.

Once this method returns null once (which indicates that this Scanner is done scanning), calling it again leads to an undefined behavior.

Returns:

a list of rows.

Throws:

KuduException - if anything went wrong

close

public RowResultIterator close()
                        throws KuduException

Closes this scanner (don't forget to call this when you're done with it!).

Closing a scanner already closed has no effect.

Returns:

a deferred object that indicates the completion of the request

Throws:

KuduException - if anything went wrong

getLimit

public long getLimit()

Returns the maximum number of rows that this scanner was configured to return.

Returns:

a long representing the maximum number of rows that can be returned

getCacheBlocks

public boolean getCacheBlocks()

Returns if this scanner was configured to cache data blocks or not.

Returns:

true if this scanner will cache blocks, else else.

getBatchSizeBytes

public long getBatchSizeBytes()

Returns the maximum number of bytes returned by the scanner, on each batch.

Returns:

a long representing the maximum number of bytes that a scanner can receive at once from a tablet server

getReadMode

public AsyncKuduScanner.ReadMode getReadMode()

Returns the ReadMode for this scanner.

Returns:

the configured read mode for this scanner

getProjectionSchema

public Schema getProjectionSchema()

Returns the projection schema of this scanner. If specific columns were not specified during scanner creation, the table schema is returned.

Returns:

the projection schema for this scanner