Package com.apple.foundationdb.record.query.expressions

Class Comparisons.TextContainsAllPrefixesComparison

java.lang.Object

com.apple.foundationdb.record.query.expressions.Comparisons.TextComparison

com.apple.foundationdb.record.query.expressions.Comparisons.TextContainsAllPrefixesComparison

All Implemented Interfaces:

PlanHashable, Comparisons.Comparison, QueryHashable

Enclosing class:

Comparisons

@API(EXPERIMENTAL)
public static class Comparisons.TextContainsAllPrefixesComparison
extends Comparisons.TextComparison

A Comparisons.TextComparison that checks for all prefixes. It carries additional meta-data about whether the comparison is "strict" or not, i.e., whether it is allowed to return false positives.

Nested Class Summary

Nested classes/interfaces inherited from interface com.apple.foundationdb.record.PlanHashable

PlanHashable.PlanHashKind

Nested classes/interfaces inherited from interface com.apple.foundationdb.record.QueryHashable

QueryHashable.QueryHashKind

Constructor Summary

Constructors

Constructor	Description
TextContainsAllPrefixesComparison(String tokenPrefixes, boolean strict, long expectedRecords, double falsePositivePercentage, String tokenizerName, String fallbackTokenizerName)
TextContainsAllPrefixesComparison(String tokenPrefixes, boolean strict, String tokenizerName, String fallbackTokenizerName)
TextContainsAllPrefixesComparison(List<String> tokenPrefixes, boolean strict, long expectedRecords, double falsePositivePercentage, String tokenizerName, String fallbackTokenizerName)
TextContainsAllPrefixesComparison(List<String> tokenPrefixes, boolean strict, String tokenizerName, String fallbackTokenizerName)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
long	getExpectedRecords()	Get the expected number of records for each token of this predicate.
double	getFalsePositivePercentage()	Get the configured false positive percentage for each token scan of this predicate.
int	hashCode()
boolean	isStrict()	Whether this comparison should be strictly evaluated.
int	planHash(PlanHashable.PlanHashKind hashKind)	Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.
int	queryHash(QueryHashable.QueryHashKind hashKind)	Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.
String	toString()

Methods inherited from class com.apple.foundationdb.record.query.expressions.Comparisons.TextComparison

eval, getComparand, getFallbackTokenizerName, getTokenizerName, getType, typelessString, validate

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.apple.foundationdb.record.query.expressions.Comparisons.Comparison

getComparand, hasMultiColumnComparand

Methods inherited from interface com.apple.foundationdb.record.PlanHashable

planHash

Constructor Detail

TextContainsAllPrefixesComparison

public TextContainsAllPrefixesComparison(@Nonnull
                                         String tokenPrefixes,
                                         boolean strict,
                                         @Nullable
                                         String tokenizerName,
                                         @Nonnull
                                         String fallbackTokenizerName)

TextContainsAllPrefixesComparison

public TextContainsAllPrefixesComparison(@Nonnull
                                         String tokenPrefixes,
                                         boolean strict,
                                         long expectedRecords,
                                         double falsePositivePercentage,
                                         @Nullable
                                         String tokenizerName,
                                         @Nonnull
                                         String fallbackTokenizerName)

TextContainsAllPrefixesComparison

public TextContainsAllPrefixesComparison(@Nonnull
                                         List<String> tokenPrefixes,
                                         boolean strict,
                                         @Nullable
                                         String tokenizerName,
                                         @Nonnull
                                         String fallbackTokenizerName)

TextContainsAllPrefixesComparison

public TextContainsAllPrefixesComparison(@Nonnull
                                         List<String> tokenPrefixes,
                                         boolean strict,
                                         long expectedRecords,
                                         double falsePositivePercentage,
                                         @Nullable
                                         String tokenizerName,
                                         @Nonnull
                                         String fallbackTokenizerName)

Method Detail

isStrict

public boolean isStrict()

Whether this comparison should be strictly evaluated. This is used during query planning to determine whether it is acceptable to return false positives.

Returns:

false if false positives are acceptable and true otherwise

getExpectedRecords

public long getExpectedRecords()

Get the expected number of records for each token of this predicate. This tweaks the behavior of this predicate when run against an index scan. In particular, this informs how much memory to use for internal data structures as part of the scan. If the number provided is larger than the number that actually gets read, then the scan is less memory efficient. If the number provided is smaller than the number that actually gets read, then the scan may have more false positives than expected.

Returns:

the expected number of insertions per child of

getFalsePositivePercentage

public double getFalsePositivePercentage()

Get the configured false positive percentage for each token scan of this predicate. This is used, along with getExpectedRecords(), determines the size of internal data structures used as part of the scan. In general, the lower this number, the more memory is used. This number refers to the false positive percentage of determining if an individual prefix is in the indexed text field of a record while scanning.

Returns:

the rate of false positives used by probabilistic data structures

equals

public boolean equals(Object o)

Overrides:

equals in class Comparisons.TextComparison

planHash

public int planHash(@Nonnull
                    PlanHashable.PlanHashKind hashKind)

Description copied from interface: PlanHashable

Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.

Specified by:

planHash in interface PlanHashable

Overrides:

planHash in class Comparisons.TextComparison

Parameters:

hashKind - the "kind" of hash to calculate. Each kind of hash has a particular logic with regards to included and excluded items.

Returns:

a stable hash code

queryHash

public int queryHash(@Nonnull
                     QueryHashable.QueryHashKind hashKind)

Description copied from interface: QueryHashable

Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.

Specified by:

queryHash in interface QueryHashable

Overrides:

queryHash in class Comparisons.TextComparison

Parameters:

hashKind - the "kind" of hash to calculate. Each kind of hash has a particular logic with regards to included and excluded items.

Returns:

a stable hash code

hashCode

public int hashCode()

Overrides:

hashCode in class Comparisons.TextComparison

toString

@Nonnull
public String toString()

Overrides:

toString in class Comparisons.TextComparison