Package org.javers.core.diff.custom

Interface CustomPropertyComparator<T,C extends PropertyChange>

Type Parameters:

T - Custom Type

C - Concrete type of PropertyChange returned by a comparator

All Superinterfaces:

CustomValueComparator<T>

public interface CustomPropertyComparator<T,C extends PropertyChange>
extends CustomValueComparator<T>

Property-scope comparator bounded to CustomType.

Custom Types are not easy to manage, use it as a last resort,
only for corner cases like comparing custom Collection types.

Typically, Custom Types are large structures (like Multimap).
Implementation should calculate diff between two objects of given Custom Type.

Usage:

 JaversBuilder.javers()
              .registerCustomType( Multimap.class, new GuavaCustomComparator())
              .build()
 

See Also:

• https://javers.org/documentation/diff-configuration/#custom-comparators
• CustomValueComparator

Method Summary

Modifier and Type	Method	Description
Optional<C>	compare(T left, T right, PropertyChangeMetadata metadata, Property property)	Called by JaVers to calculate property-to-property diff between two Custom Type objects.

Methods inherited from interface org.javers.core.diff.custom.CustomValueComparator

equals, handlesNulls, toString

Method Details

compare

Optional<C> compare(T left,
 T right,
 PropertyChangeMetadata metadata,
 Property property)

Called by JaVers to calculate property-to-property diff between two Custom Type objects. Can calculate any of concrete PropertyChange.

Implementation of compare() should be consistent with CustomValueComparator.equals(Object, Object). When compare() returns Optional.empty(), equals() should return false.

Parameters:

left - left (or old) value

right - right (or current) value

metadata - call PropertyChangeMetadata.getAffectedCdoId() to get Id of domain object being compared

property - property being compared

Returns:

should return Optional.empty() if compared objects are the same