com.bigdata.bop.ap

Class SampleIndex<E>

java.lang.Object

com.bigdata.bop.CoreBaseBOp

com.bigdata.bop.BOpBase

com.bigdata.bop.AbstractAccessPathOp<E>

com.bigdata.bop.ap.SampleIndex<E>

Type Parameters:

E - The generic type of the elements materialized from that index.

All Implemented Interfaces:

BOp, IPropertySet, Serializable, Cloneable

public class SampleIndex<E>
extends AbstractAccessPathOp<E>

Sampling operator for the IAccessPath implied by an IPredicate.

Version:

$Id: AbstractSampleIndex.java 3672 2010-09-28 23:39:42Z thompsonbry $

Author:

Bryan Thompson

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SampleIndex.AcceptanceSetOffsetSampler An implementation based on an acceptance set of offsets which have been accepted.
static class	SampleIndex.AccessPathSample<E> A sample from an access path.
static interface	SampleIndex.Annotations Known annotations.
static class	SampleIndex.BitVectorOffsetSampler Return a randomly selected ordered array of offsets in the given half-open range.
static class	SampleIndex.EntireRangeOffsetSampler Returns all offsets in the half-open range, but may only be used when the limit GTE the range count.
static interface	SampleIndex.IOffsetSampler Interface for obtaining an array of tuple offsets to be sampled.
static class	SampleIndex.SampleType Typesafe enumeration of different kinds of index sampling strategies.
static class	SampleIndex.SmartOffsetSampler A smart implementation which uses whichever implementation is most efficient for the limit and key range to be sampled.

Field Summary

Fields inherited from class com.bigdata.bop.CoreBaseBOp

DEFAULT_INITIAL_CAPACITY

Fields inherited from interface com.bigdata.bop.BOp

NOANNS, NOARGS

Constructor Summary

Constructors

Constructor and Description
SampleIndex(BOp[] args, Map<String,Object> annotations)
SampleIndex(SampleIndex<E> op)

Method Summary

Methods

Modifier and Type	Method and Description
E[]	eval(BOpContextBase context) Return a sample from the access path associated with the SampleIndex.Annotations.PREDICATE.
IPredicate<E>	getPredicate()
SampleIndex.SampleType	getSampleType()
int	limit()
long	seed()

Methods inherited from class com.bigdata.bop.BOpBase

__replaceArg, _clearProperty, _set, _setProperty, annotations, annotationsCopy, annotationsEqual, annotationsRef, argIterator, args, argsCopy, arity, clearAnnotations, clearProperty, deepCopy, deepCopy, get, getProperty, setArg, setProperty, setUnboundProperty, toArray, toArray

Methods inherited from class com.bigdata.bop.CoreBaseBOp

annotationsEqual, annotationsToString, annotationsToString, annotationValueToString, checkArgs, clone, equals, getEvaluationContext, getId, getProperty, getRequiredProperty, hashCode, indent, isController, mutation, shortenName, toShortString, toString, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SampleIndex

public SampleIndex(SampleIndex<E> op)

SampleIndex

public SampleIndex(BOp[] args,
           Map<String,Object> annotations)

Method Detail

limit

public int limit()

See Also:

SampleIndex.Annotations.LIMIT

seed

public long seed()

See Also:

SampleIndex.Annotations.SEED

getSampleType

public SampleIndex.SampleType getSampleType()

See Also:

SampleIndex.Annotations.SAMPLE_TYPE

getPredicate

public IPredicate<E> getPredicate()

eval

public E[] eval(BOpContextBase context)

Return a sample from the access path associated with the SampleIndex.Annotations.PREDICATE.