Package one.microstream.equality

Interface Equalator<T>

Type Parameters:

T - type of objects to compare

All Known Subinterfaces:

HashEqualator<T>, HashEqualator.IdentityHashEqualator<E>, HashEqualator.ImmutableHashEqualator<E>, HashEqualator.ImmutableValueTypeHashEqualator<E>, HashEqualator.ValueTypeHashEqualator<E>, IdentityEqualator<E>, ValueTypeEqualator<E>

All Known Implementing Classes:

Equalator.ComparatorWrapper, Equalator.Sequence, PersistenceTypeDescriptionMember.IdentityHashEqualator, TypePair.HashEquality

public interface Equalator<T>

A equalator function which checks if two given objects are equal or not. Since it is very close to the Comparator, but has limited return value, it is possible to wrap an existing comparator with the Wrap(Comparator) method.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	Equalator.ComparatorWrapper<T>
static interface	Equalator.Provider<T>
static class	Equalator.Sequence<T>	Useful for implementing SQL-like "GROUP BY" for collections.

Method Summary

Modifier and Type	Method	Description
static <E> Equalator<E>	Chain(Equalator<? super E>... equalators)
boolean	equal(T object1, T object2)	Compares the two given objects (object1 and object2) depending on the implementation.
static <E> Equalator<E>	identity()
default Predicate<T>	sample(T sample)	Creates a Predicate that checks every given object with equality against the set sample.
static <E> Equalator<E>	value()
static <E> Equalator<E>	Wrap(Comparator<? super E> comparator)	Wraps a given Comparator into an Equalator.

Method Details

equal

boolean equal(T object1, T object2)

Compares the two given objects (object1 and object2) depending on the implementation.

Parameters:

object1 - as first object to check equality on

object2 - as second object to check equality on

Returns:

true if object1 equals object2, false if not.

sample

default Predicate<T> sample(T sample)

Creates a Predicate that checks every given object with equality against the set sample.

Parameters:

sample - which is compared

Returns:

function that compares the input of the function with the given sample

Wrap

static <E> Equalator<E> Wrap(Comparator<? super E> comparator)

Wraps a given Comparator into an Equalator. Resulting Equalator returns true if the comparator return 0. In all other cases false is returned.

Type Parameters:

E - type of objects to compare

Parameters:

comparator - to wrap insinde a new Equalator

Returns:

a new Equalator which executes the given comparator

Chain

@SafeVarargs static <E> Equalator<E> Chain(Equalator<? super E>... equalators)

Type Parameters:

E - type of objects to compare

Parameters:

equalators - to chain together

Returns:

Chained Equalator and only if all Equalators return true, this created Equalator returns true.

value

static <E> Equalator<E> value()

Type Parameters:

E - type of objects to compare

Returns:

Static equalator which defines equality through the Object.equals(Object) method.

identity

static <E> Equalator<E> identity()

Type Parameters:

E - type of objects to compare

Returns:

Static equalator which defines equality through the '=='-Operator.