Interface Hashable
Defines a method that a class implements to provide hashing functionality.
Hashes are very important as a way to efficiently lookup objects in
hash-based data structures. This interface aims to facilitate the use of
those structures by allowing classes to define custom hashing strategies.
-
PhpCommon\Comparison\Hashable
implements
PhpCommon\Comparison\Equatable
Methods summary
public
integer
|
#
getHash( )
Returns a hash code for the current object.
Returns a hash code for the current object.
This method has the following properties:
- It is consistent: for any
$x, multiple invocations of $x->getHash() consistently return the same value provided that $x remains unchanged according to the definition of the equivalence. The hash need not remain consistent from one execution of an application to another execution of the same application.
- It is distributable across equivalence: for any instance of
PhpCommon\Comparison\Hashable $x and $y, if $x->equals($y), then $x->getHash() === $y->getHash(). It is not necessary that the hash be distributable across inequivalence. If $x->equals($y) is false, $x->getHash() === $y->getHash() may still be true.
When implementing this method it is recommended to use a fast algorithm
that produces reasonably different results for unequal values, and
shift the heavy comparison logic to
PhpCommon\Comparison\Equatable::equals().
Returns
integer
The hash code for the current object.
|