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, Iterable<Result>, ResultScanner

Direct Known Subclasses:

ClientSmallReversedScanner

@InterfaceAudience.Public
@InterfaceStability.Evolving
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, currentRegion, lastNext, lastResult, maxScannerResultSize, rpcControllerFactory, scan, scanMetricsPublished, scannerTimeout

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

scanMetrics

Constructor Summary

ReversedClientScanner(org.apache.hadoop.conf.Configuration conf, Scan scan, TableName tableName, HConnection connection)
Create a new ReversibleClientScanner for the specified table Note that the passed Scan's start row maybe changed.

Method Summary

protected boolean	checkScanStopRow(byte[] startKey)
protected byte[]	createClosestRowBefore(byte[] row) Create the closest row before the specified row
protected ScannerCallable	getScannerCallable(byte[] localStartKey, int nbRows, byte[] locateStartRow)
protected boolean	nextScanner(int nbRows, boolean done)

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

close, getCacheSize, getConnection, getMaxResultSize, getScan, getScannerCallable, getTable, getTableName, getTimestamp, initializeScannerInConstruction, loadCache, next, renewLease, writeScanMetrics

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

getScanMetrics, initScanMetrics, iterator, next

Methods inherited from class java.lang.Object

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

Constructor Detail

ReversedClientScanner

public ReversedClientScanner(org.apache.hadoop.conf.Configuration conf,
                             Scan scan,
                             TableName tableName,
                             HConnection connection)
                      throws IOException

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

Parameters:

conf - The Configuration to use.

scan - Scan to use in this scanner

tableName - The table that we wish to scan

connection - Connection identifying the cluster

Throws:

IOException

Method Detail

nextScanner

protected boolean nextScanner(int nbRows,
                              boolean done)
                       throws IOException

Overrides:

nextScanner in class ClientScanner

Throws:

IOException

getScannerCallable

protected ScannerCallable getScannerCallable(byte[] localStartKey,
                                             int nbRows,
                                             byte[] locateStartRow)

checkScanStopRow

protected boolean checkScanStopRow(byte[] startKey)

Overrides:

checkScanStopRow in class ClientScanner

createClosestRowBefore

protected byte[] createClosestRowBefore(byte[] row)

Create the closest row before the specified row

Parameters:

row -

Returns:

a new byte array which is the closest front row of the specified one