de.caff.generics

Class Subjectivity

java.lang.Object

de.caff.generics.Subjectivity

public class Subjectivity
extends java.lang.Object

A subjective view on objects.

This class allows to substitute objects with views which expose different Object.equals(Object) and Object.hashCode() implementations.

It does not work on primitive types, but their boxed counterparts. If you provide a Subjective for a boxed primitive class it is also a good idea to provide one for its one-dimensional array type. E.g. if you provide a subjective for Double you should also provide one for double[].

Hashing of arrays is usually done flat, but you can change this by setting the deep flag in the constructors to true. This will influence all arrays, not just the ones which are handled by subjectives.

Since:

February 13, 2023

Author:

Rammi

Constructor Summary

Constructors

Constructor and Description
Subjectivity(boolean deep, java.lang.Iterable<Subjective<?>> subjects) Constructor.
Subjectivity(boolean deep, Subjective<?>... subjects) Constructor.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	substitute(java.lang.Object obj) Substitute the given object.
java.lang.Object	substitute0(java.lang.Object obj) Substitute the given object which may be null.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Subjectivity

public Subjectivity(boolean deep,
                    @NotNull
                    java.lang.Iterable<Subjective<?>> subjects)

Constructor.

Parameters:

deep - make equals and hashcode work deep?

subjects - subjective views used by this subjectivity

Subjectivity

public Subjectivity(boolean deep,
                    @NotNull
                    Subjective<?>... subjects)

Constructor.

Parameters:

deep - make equals and hashcode work deep?

subjects - subjective views used by this subjectivity

Method Detail

substitute

@NotNull
public java.lang.Object substitute(@NotNull
                                            java.lang.Object obj)

Substitute the given object.

It is strictly recommended to use a substitute only for checking equality or hashing.

Parameters:

obj - object to be substituted, not null

Returns:

obj if there is no substitution for the given object
or a substitute which stands in for the object

See Also:

substitute0(Object)

substitute0

@Nullable
public java.lang.Object substitute0(@Nullable
                                              java.lang.Object obj)

Substitute the given object which may be null.

Parameters:

obj - object to be substituted, possibly null

Returns:

obj if there is no substitution for the given object, or it is null
or a substitute which stands in for the object