org.apache.accumulo.core.client

Interface ScannerBase

All Superinterfaces:

Iterable<Map.Entry<Key,Value>>

All Known Subinterfaces:

BatchDeleter, BatchScanner, Scanner

All Known Implementing Classes:

ClientSideIteratorScanner, IsolatedScanner, MockBatchDeleter, MockBatchScanner, MockScanner, MockScannerBase, org.apache.accumulo.core.client.impl.ScannerOptions

public interface ScannerBase
extends Iterable<Map.Entry<Key,Value>>

This class hosts configuration methods that are shared between different types of scanners.

Method Summary

Methods

Modifier and Type	Method and Description
void	addScanIterator(IteratorSetting cfg) Add a server-side scan iterator.
void	clearColumns() Clears the columns to be fetched (useful for resetting the scanner for reuse).
void	clearScanIterators() Clears scan iterators prior to returning a scanner to the pool.
void	close() Closes any underlying connections on the scanner
void	fetchColumn(org.apache.hadoop.io.Text colFam, org.apache.hadoop.io.Text colQual) Adds a column to the list of columns that will be fetched by this scanner.
void	fetchColumnFamily(org.apache.hadoop.io.Text col) Adds a column family to the list of columns that will be fetched by this scanner.
long	getTimeout(TimeUnit timeUnit) Returns the setting for how long a scanner will automatically retry when a failure occurs.
Iterator<Map.Entry<Key,Value>>	iterator() Returns an iterator over an accumulo table.
void	removeScanIterator(String iteratorName) Remove an iterator from the list of iterators.
void	setTimeout(long timeOut, TimeUnit timeUnit) This setting determines how long a scanner will automatically retry when a failure occurs.
void	updateScanIteratorOption(String iteratorName, String key, String value) Update the options for an iterator.

Method Detail

addScanIterator

void addScanIterator(IteratorSetting cfg)

Add a server-side scan iterator.

Parameters:

cfg - fully specified scan-time iterator, including all options for the iterator. Any changes to the iterator setting after this call are not propagated to the stored iterator.

Throws:

IllegalArgumentException - if the setting conflicts with existing iterators

removeScanIterator

void removeScanIterator(String iteratorName)

Remove an iterator from the list of iterators.

Parameters:

iteratorName - nickname used for the iterator

updateScanIteratorOption

void updateScanIteratorOption(String iteratorName,
                            String key,
                            String value)

Update the options for an iterator. Note that this does not change the iterator options during a scan, it just replaces the given option on a configured iterator before a scan is started.

Parameters:

iteratorName - the name of the iterator to change

key - the name of the option

value - the new value for the named option

fetchColumnFamily

void fetchColumnFamily(org.apache.hadoop.io.Text col)

Adds a column family to the list of columns that will be fetched by this scanner. By default when no columns have been added the scanner fetches all columns.

Parameters:

col - the column family to be fetched

fetchColumn

void fetchColumn(org.apache.hadoop.io.Text colFam,
               org.apache.hadoop.io.Text colQual)

Adds a column to the list of columns that will be fetched by this scanner. The column is identified by family and qualifier. By default when no columns have been added the scanner fetches all columns.

Parameters:

colFam - the column family of the column to be fetched

colQual - the column qualifier of the column to be fetched

clearColumns

void clearColumns()

Clears the columns to be fetched (useful for resetting the scanner for reuse). Once cleared, the scanner will fetch all columns.

clearScanIterators

void clearScanIterators()

Clears scan iterators prior to returning a scanner to the pool.

iterator

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

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>>

Returns:

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

setTimeout

void setTimeout(long timeOut,
              TimeUnit timeUnit)

This setting determines how long a scanner will automatically retry when a failure occurs. By default a scanner will retry forever. Setting to zero or Long.MAX_VALUE and TimeUnit.MILLISECONDS means to retry forever.

Parameters:

timeUnit - determines how timeout is interpreted

Since:

1.5.0

getTimeout

long getTimeout(TimeUnit timeUnit)

Returns the setting for how long a scanner will automatically retry when a failure occurs.

Returns:

the timeout configured for this scanner

Since:

1.5.0

close

void close()

Closes any underlying connections on the scanner

Since:

1.5.0