org.apache.hadoop.hbase.client

Class AbstractClientScanner

java.lang.Object

org.apache.hadoop.hbase.client.AbstractClientScanner

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<Result>, ResultScanner

Direct Known Subclasses:

ClientScanner, ClientSideRegionScanner, TableSnapshotScanner

@InterfaceAudience.Private
public abstract class AbstractClientScanner
extends Object
implements ResultScanner

Helper class for custom client scanners.

Field Summary

Fields

Modifier and Type	Field and Description
protected ScanMetrics	scanMetrics

Constructor Summary

Constructors

Constructor and Description
AbstractClientScanner()

Method Summary

Methods

Modifier and Type	Method and Description
ScanMetrics	getScanMetrics() Used internally accumulating metrics on scan.
protected void	initScanMetrics(Scan scan) Check and initialize if application wants to collect scan metrics
Iterator<Result>	iterator()
Result[]	next(int nbRows) Get nbRows rows.
abstract boolean	renewLease() Allow the client to renew the scanner's lease on the server.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.client.ResultScanner

close, next

Field Detail

scanMetrics

protected ScanMetrics scanMetrics

Constructor Detail

AbstractClientScanner

public AbstractClientScanner()

Method Detail

initScanMetrics

protected void initScanMetrics(Scan scan)

Check and initialize if application wants to collect scan metrics

getScanMetrics

public ScanMetrics getScanMetrics()

Used internally accumulating metrics on scan. To enable collection of metrics on a Scanner, call Scan.setScanMetricsEnabled(boolean). These metrics are cleared at key transition points. Metrics are accumulated in the Scan object itself.

Returns:

Returns the running ScanMetrics instance or null if scan metrics not enabled.

See Also:

Scan.getScanMetrics()

next

public Result[] next(int nbRows)
              throws IOException

Get nbRows rows. How many RPCs are made is determined by the Scan.setCaching(int) setting (or hbase.client.scanner.caching in hbase-site.xml).

Specified by:

next in interface ResultScanner

Parameters:

nbRows - number of rows to return

Returns:

Between zero and nbRows RowResults. Scan is done if returned array is of zero-length (We never return null).

Throws:

IOException

iterator

public Iterator<Result> iterator()

Specified by:

iterator in interface Iterable<Result>

renewLease

public abstract boolean renewLease()

Allow the client to renew the scanner's lease on the server.

Returns:

true if the lease was successfully renewed, false otherwise.