Package org.apache.accumulo.core.clientImpl

Class ScannerImpl

java.lang.Object

org.apache.accumulo.core.clientImpl.ScannerOptions

org.apache.accumulo.core.clientImpl.ScannerImpl

All Implemented Interfaces:

AutoCloseable, Iterable<Map.Entry<Key,Value>>, Scanner, ScannerBase

public class ScannerImpl
extends ScannerOptions
implements Scanner

provides scanner functionality "Clients can iterate over multiple column families, and there are several mechanisms for limiting the rows, columns, and timestamps traversed by a scan. For example, we could restrict [a] scan ... to only produce anchors whose columns match [a] regular expression ..., or to only produce anchors whose timestamps fall within ten days of the current time."

Field Summary

Fields inherited from class org.apache.accumulo.core.clientImpl.ScannerOptions

batchTimeOut, classLoaderContext, executionHints, fetchedColumns, serverSideIteratorList, serverSideIteratorOptions, timeOut

Constructor Summary

Constructors

Constructor	Description
ScannerImpl(ClientContext context, TableId tableId, Authorizations authorizations)

Method Summary

Modifier and Type	Method	Description
void	close()	Closes any underlying connections on the scanner.
void	disableIsolation()	Disables row isolation.
void	enableIsolation()	Enables row isolation.
Authorizations	getAuthorizations()	Returns the authorizations that have been set on the scanner
int	getBatchSize()	Returns the batch size (number of Key/Value pairs) that will be fetched at a time from a tablet server.
Range	getRange()	Returns the range of keys to scan over.
long	getReadaheadThreshold()	The number of batches of Key/Value pairs returned before the Scanner will begin to prefetch the next batch
Iterator<Map.Entry<Key,Value>>	iterator()	Returns an iterator over an accumulo table.
void	setBatchSize(int size)	Sets the number of Key/Value pairs that will be fetched at a time from a tablet server.
void	setRange(Range range)	Sets the range of keys to scan over.
void	setReadaheadThreshold(long batches)	Sets the number of batches of Key/Value pairs returned before the Scanner will begin to prefetch the next batch

Methods inherited from class org.apache.accumulo.core.clientImpl.ScannerOptions

addScanIterator, clearClassLoaderContext, clearColumns, clearSamplerConfiguration, clearScanIterators, fetchColumn, fetchColumn, fetchColumnFamily, getBatchTimeout, getClassLoaderContext, getFetchedColumns, getSamplerConfiguration, getTimeout, removeScanIterator, setBatchTimeout, setClassLoaderContext, setExecutionHints, setOptions, setSamplerConfiguration, setTimeout, updateScanIteratorOption

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface org.apache.accumulo.core.client.ScannerBase

addScanIterator, clearClassLoaderContext, clearColumns, clearSamplerConfiguration, clearScanIterators, fetchColumn, fetchColumn, fetchColumn, fetchColumnFamily, fetchColumnFamily, getBatchTimeout, getClassLoaderContext, getSamplerConfiguration, getTimeout, removeScanIterator, setBatchTimeout, setClassLoaderContext, setExecutionHints, setSamplerConfiguration, setTimeout, updateScanIteratorOption

Constructor Detail

ScannerImpl

public ScannerImpl(ClientContext context,
                   TableId tableId,
                   Authorizations authorizations)

Method Detail

setRange

public void setRange(Range range)

Description copied from interface: Scanner

Sets the range of keys to scan over.

Specified by:

setRange in interface Scanner

Parameters:

range - key range to begin and end scan

getRange

public Range getRange()

Description copied from interface: Scanner

Returns the range of keys to scan over.

Specified by:

getRange in interface Scanner

Returns:

the range configured for this scanner

setBatchSize

public void setBatchSize(int size)

Description copied from interface: Scanner

Sets the number of Key/Value pairs that will be fetched at a time from a tablet server.

Specified by:

setBatchSize in interface Scanner

Parameters:

size - the number of Key/Value pairs to fetch per call to Accumulo

getBatchSize

public int getBatchSize()

Description copied from interface: Scanner

Returns the batch size (number of Key/Value pairs) that will be fetched at a time from a tablet server.

Specified by:

getBatchSize in interface Scanner

Returns:

the batch size configured for this scanner

iterator

public Iterator<Map.Entry<Key,Value>> iterator()

Description copied from interface: ScannerBase

Returns an iterator over an accumulo table. This iterator uses the options that are currently set for its lifetime, so setting options will have no effect on existing iterators.

Keys returned by the iterator are not guaranteed to be in sorted order.

Specified by:

iterator in interface Iterable<Map.Entry<Key,Value>>

Specified by:

iterator in interface ScannerBase

Overrides:

iterator in class ScannerOptions

Returns:

an iterator over Key,Value pairs which meet the restrictions set on the scanner

getAuthorizations

public Authorizations getAuthorizations()

Description copied from interface: ScannerBase

Returns the authorizations that have been set on the scanner

Specified by:

getAuthorizations in interface ScannerBase

Overrides:

getAuthorizations in class ScannerOptions

Returns:

The authorizations set on the scanner instance

enableIsolation

public void enableIsolation()

Description copied from interface: Scanner

Enables row isolation. Writes that occur to a row after a scan of that row has begun will not be seen if this option is enabled.

Specified by:

enableIsolation in interface Scanner

disableIsolation

public void disableIsolation()

Description copied from interface: Scanner

Disables row isolation. Writes that occur to a row after a scan of that row has begun may be seen if this option is enabled.

Specified by:

disableIsolation in interface Scanner

setReadaheadThreshold

public void setReadaheadThreshold(long batches)

Description copied from interface: Scanner

Sets the number of batches of Key/Value pairs returned before the Scanner will begin to prefetch the next batch

Specified by:

setReadaheadThreshold in interface Scanner

Parameters:

batches - Non-negative number of batches

getReadaheadThreshold

public long getReadaheadThreshold()

Description copied from interface: Scanner

The number of batches of Key/Value pairs returned before the Scanner will begin to prefetch the next batch

Specified by:

getReadaheadThreshold in interface Scanner

Returns:

Number of batches before read-ahead begins

close

public void close()

Description copied from interface: ScannerBase

Closes any underlying connections on the scanner. This may invalidate any iterators derived from the Scanner, causing them to throw exceptions.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface ScannerBase

Overrides:

close in class ScannerOptions