Package org.apache.accumulo.core.client.rfile

Interface RFile.ScannerOptions

All Known Subinterfaces:

RFile.ScannerFSOptions

Enclosing class:

RFile

public static interface RFile.ScannerOptions

This is an intermediate interface in a larger builder pattern. Supports setting optional parameters for reading RFile(s) and building a scanner over RFile(s).

Since:

1.8.0

Method Summary

Modifier and Type	Method	Description
Scanner	build()
RFile.ScannerOptions	withAuthorizations(Authorizations auths)	The authorizations passed here will be used to filter Keys, from the Scanner, based on the content of the column visibility field.
RFile.ScannerOptions	withBounds(Range range)	This option allows limiting the Scanner from reading data outside of a given range.
RFile.ScannerOptions	withDataCache(long cacheSize)	Enabling this option will cache RFiles data in memory.
RFile.ScannerOptions	withIndexCache(long cacheSize)	Enabling this option will cache RFiles indexes in memory.
RFile.ScannerOptions	withoutSystemIterators()	By default the Scanner created will setup the default Accumulo system iterators.
RFile.ScannerOptions	withTableProperties(Iterable<Map.Entry<String,String>> props)	Construct the Scanner with iterators specified in a tables properties.
RFile.ScannerOptions	withTableProperties(Map<String,String> props)

Method Details

withoutSystemIterators

RFile.ScannerOptions withoutSystemIterators()

By default the Scanner created will setup the default Accumulo system iterators. The iterators do things like the following :

• Suppress deleted data
• Filter based on @link Authorizations
• Filter columns specified by functions like ScannerBase.fetchColumn(Text, Text) and ScannerBase.fetchColumnFamily(Text)

Calling this method will turn off these system iterators and allow reading the raw data in an RFile. When reading the raw data, delete data and delete markers may be seen. Delete markers are Keys with the delete flag set.

Disabling system iterators will cause withAuthorizations(Authorizations), ScannerBase.fetchColumn(Text, Text), and ScannerBase.fetchColumnFamily(Text) to throw runtime exceptions.

Returns:

this

withAuthorizations

RFile.ScannerOptions withAuthorizations(Authorizations auths)

The authorizations passed here will be used to filter Keys, from the Scanner, based on the content of the column visibility field.

Parameters:

auths - scan with these authorizations

Returns:

this

withDataCache

RFile.ScannerOptions withDataCache(long cacheSize)

Enabling this option will cache RFiles data in memory. This option is useful when doing lots of random accesses.

Parameters:

cacheSize - the size of the data cache in bytes.

Returns:

this

withIndexCache

RFile.ScannerOptions withIndexCache(long cacheSize)

Enabling this option will cache RFiles indexes in memory. Index data within a RFile is used to find data when seeking to a Key. This option is useful when doing lots of random accesses.

Parameters:

cacheSize - the size of the index cache in bytes.

Returns:

this

withBounds

RFile.ScannerOptions withBounds(Range range)

This option allows limiting the Scanner from reading data outside of a given range. A scanner will not see any data outside of this range even if the RFile(s) have data outside the range.

Returns:

this

withTableProperties

RFile.ScannerOptions withTableProperties(Iterable<Map.Entry<String,String>> props)

Construct the Scanner with iterators specified in a tables properties. Properties for a table can be obtained by calling TableOperations.getProperties(String). Any property that impacts file behavior regardless of whether it has the Property.TABLE_PREFIX may be accepted and used. For example, cache and crypto properties could be passed here.

Parameters:

props - iterable over Accumulo table key value properties.

Returns:

this

withTableProperties

RFile.ScannerOptions withTableProperties(Map<String,String> props)

Parameters:

props - a map instead of an Iterable

Returns:

this

See Also:

• Any property that impacts file behavior regardless of whether it has the Property#TABLE_PREFIX may be accepted and used. For example, cache and crypto properties could be passed here.

build

Scanner build()

Returns:

a Scanner over RFile using the specified options.