org.apache.hadoop.hbase.client

Class ReversedClientScanner

java.lang.Object

org.apache.hadoop.hbase.client.AbstractClientScanner

org.apache.hadoop.hbase.client.ClientScanner

org.apache.hadoop.hbase.client.ReversedClientScanner

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<Result>, ResultScanner

@InterfaceAudience.Private
public class ReversedClientScanner
extends ClientScanner

A reversed client scanner which support backward scanning

Field Summary

Fields inherited from class org.apache.hadoop.hbase.client.ClientScanner

cache, caching, callable, caller, closed, conf, currentRegion, lastNext, lastResult, maxScannerResultSize, pool, primaryOperationTimeout, rpcControllerFactory, scan, scanMetricsPublished, scannerTimeout, tableName

Fields inherited from class org.apache.hadoop.hbase.client.AbstractClientScanner

scanMetrics

Constructor Summary

Constructors

Constructor and Description
ReversedClientScanner(org.apache.hadoop.conf.Configuration conf, Scan scan, TableName tableName, ClusterConnection connection, RpcRetryingCallerFactory rpcFactory, RpcControllerFactory controllerFactory, ExecutorService pool, int primaryOperationTimeout) Create a new ReversibleClientScanner for the specified table Note that the passed Scan's start row maybe changed.

Method Summary

Modifier and Type	Method and Description
protected ReversedScannerCallable	createScannerCallable() Will be called in moveToNextRegion to create ScannerCallable.
protected boolean	setNewStartKey() Will be called in moveToNextRegion when currentRegion is null.

Methods inherited from class org.apache.hadoop.hbase.client.ClientScanner

addEstimatedSize, close, getCacheCount, getCacheSize, getCaching, getConf, getConnection, getMaxResultSize, getPool, getPrimaryOperationTimeout, getRetries, getScan, getScannerTimeout, getTable, getTimestamp, initCache, initSyncCache, loadCache, moveToNextRegion, next, nextWithSyncCache, renewLease, writeScanMetrics

Methods inherited from class org.apache.hadoop.hbase.client.AbstractClientScanner

getScanMetrics, initScanMetrics

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

iterator, next

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

ReversedClientScanner

public ReversedClientScanner(org.apache.hadoop.conf.Configuration conf,
                             Scan scan,
                             TableName tableName,
                             ClusterConnection connection,
                             RpcRetryingCallerFactory rpcFactory,
                             RpcControllerFactory controllerFactory,
                             ExecutorService pool,
                             int primaryOperationTimeout)
                      throws IOException

Create a new ReversibleClientScanner for the specified table Note that the passed Scan's start row maybe changed.

Parameters:

conf -

scan -

tableName -

connection -

pool -

primaryOperationTimeout -

Throws:

IOException

Method Detail

setNewStartKey

protected boolean setNewStartKey()

Description copied from class: ClientScanner

Will be called in moveToNextRegion when currentRegion is null. Abstract because for normal scan, we will start next scan from the endKey of the currentRegion, and for reversed scan, we will start next scan from the startKey of the currentRegion.

Specified by:

setNewStartKey in class ClientScanner

Returns:

false if we have reached the stop row. Otherwise true.

createScannerCallable

protected ReversedScannerCallable createScannerCallable()

Description copied from class: ClientScanner

Will be called in moveToNextRegion to create ScannerCallable. Abstract because for reversed scan we need to create a ReversedScannerCallable.

Specified by:

createScannerCallable in class ClientScanner