Package com.apple.foundationdb.record.query.plan.temp

Class ComparisonRange

java.lang.Object

com.apple.foundationdb.record.query.plan.temp.ComparisonRange

All Implemented Interfaces:

PlanHashable

@API(EXPERIMENTAL)
public class ComparisonRange
extends Object
implements PlanHashable

A set of compatible comparisons on a single field of a KeyExpression representing a contiguous range of values for that field.

A ComparisonRange is similar to a ScanComparisons but represents a contiguous range of values for a single field, rather than for an entire KeyExpression. A comparison range is effectively a sum type, with the following options:

• An empty set of comparisons, indicating that the entire universe of possible values is in the range.
• An equality comparison on the field. There can only be a single such comparison. For example, single comparison of the form EQUALS "foo".
• A set of inequality comparisons that define a single contiguous range of values. For example, the combination of the comparisons > 8 and < 30. The comparison range may include redundant comparisons by contract, but it may or may not simplify the range into a more compact form. For example, the comparison range can include the comparisons > 8, < 30, and < 20, but it may optionally simplify this to > 8 and < 20. Note that this behavior is not fully implemented right now; similarly, this implementation does not currently convert a range such as < 8 and > 30 to an empty range. However, this normalization logic will be added here in the future.

A ComparisonRange is an immutable object that provides a variety of methods for producing new range from the current one and some Comparisons.Comparison objects. For example, see tryToAdd(Comparisons.Comparison) and from(Comparisons.Comparison).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ComparisonRange.MergeResult	Class to represent the outcome of a merge operation.
static class	ComparisonRange.Type	Comparison ranges can be divided into three types, with distinct planning behaviour: Empty ranges, to which any comparison can be added. Equality ranges, to which only the same (equality) comparison can be added. Inequality ranges, to which any other comparison can be added. This behavior is defined in tryToAdd(Comparisons.Comparison).

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

PlanHashable.PlanHashKind

Field Summary

Fields

Modifier and Type	Field	Description
static ComparisonRange	EMPTY

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
<M extends Message> Boolean	eval(FDBRecordStoreBase<M> store, EvaluationContext context, Object value)
static Optional<ComparisonRange>	from(Comparisons.Comparison comparison)
Comparisons.Comparison	getEqualityComparison()
List<Comparisons.Comparison>	getInequalityComparisons()
ComparisonRange.Type	getRangeType()
int	hashCode()
boolean	isEmpty()
boolean	isEquality()
boolean	isInequality()
ComparisonRange.MergeResult	merge(Comparisons.Comparison comparison)
ComparisonRange.MergeResult	merge(ComparisonRange comparisonRange)
int	planHash(PlanHashable.PlanHashKind hashKind)	Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.
String	toString()
Optional<ComparisonRange>	tryToAdd(Comparisons.Comparison comparison)

Methods inherited from class java.lang.Object

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

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

planHash

Field Detail

EMPTY

public static final ComparisonRange EMPTY

Method Detail

isEmpty

public boolean isEmpty()

isEquality

public boolean isEquality()

isInequality

public boolean isInequality()

getRangeType

@Nonnull
public ComparisonRange.Type getRangeType()

getEqualityComparison

@Nonnull
public Comparisons.Comparison getEqualityComparison()

getInequalityComparisons

@Nullable
public List<Comparisons.Comparison> getInequalityComparisons()

eval

public <M extends Message> Boolean eval(@Nonnull
                                        FDBRecordStoreBase<M> store,
                                        @Nonnull
                                        EvaluationContext context,
                                        @Nullable
                                        Object value)

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

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

tryToAdd

@Nonnull
public Optional<ComparisonRange> tryToAdd(@Nonnull
                                          Comparisons.Comparison comparison)

merge

@Nonnull
public ComparisonRange.MergeResult merge(@Nonnull
                                         Comparisons.Comparison comparison)

merge

@Nonnull
public ComparisonRange.MergeResult merge(@Nonnull
                                         ComparisonRange comparisonRange)

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

from

@Nonnull
public static Optional<ComparisonRange> from(@Nonnull
                                             Comparisons.Comparison comparison)