com.bigdata.rdf.spo

Class ContextAdvancer

java.lang.Object

cutthecrap.utils.striterators.FilterBase

com.bigdata.btree.filter.Advancer<SPO>

com.bigdata.rdf.spo.ContextAdvancer

All Implemented Interfaces:

ITupleFilter<SPO>, IFilter, IPropertySet, Serializable, Cloneable

public class ContextAdvancer
extends Advancer<SPO>

Advancer for a quads index whose last key component is the "context position (such as SPOC or SOPC). The advancer will skip to first possible key for the next distinct triple for each quad which it visits. This is a cheap way to impose a "DISTINCT" filter using an index scan and works well for both local and scale-out indices.

You have to use IRangeQuery.CURSOR to request an ITupleCursor when using an Advancer pattern.

Version:

$Id$

Author:

Bryan Thompson

See Also:

Serialized Form

Field Summary

Fields inherited from class com.bigdata.btree.filter.Advancer

log, src

Constructor Summary

Constructors

Constructor and Description
ContextAdvancer()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	advance(ITuple<SPO> tuple) Offers an opportunity to advance the source ITupleCursor to a new key using {@link ITupleCursor#seek(byte[]).

Methods inherited from class com.bigdata.btree.filter.Advancer

filterOnce, init

Methods inherited from class cutthecrap.utils.striterators.FilterBase

addFilter, filter, getProperty, getRequiredProperty, setProperty, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface cutthecrap.utils.striterators.IFilter

filter

Methods inherited from interface cutthecrap.utils.striterators.IPropertySet

getProperty

Constructor Detail

ContextAdvancer

public ContextAdvancer()

Method Detail

advance

protected void advance(ITuple<SPO> tuple)

Description copied from class: Advancer

Offers an opportunity to advance the source ITupleCursor to a new key using {@link ITupleCursor#seek(byte[]).

Specified by:

advance in class Advancer<SPO>

Parameters:

tuple - The current value.