Interface Comparable

Defines a method that a class implements to provide natural order of sorting to instances.

This interface imposes a total ordering on the objects of each class that implements it. This ordering is referred to as the natural ordering of the class, and the method PhpCommon\Comparison\Comparable::compareTo() is referred to as its natural comparison method.

The natural ordering for a class C is said to be consistent with PhpCommon\Comparison\Equatable::equals() if and only if $a->compareTo($b) === 0 has the same boolean value as $a->equals($b) for every $a and $b of class C.

It is strongly recommended (though not required) that natural orderings be consistent with PhpCommon\Comparison\Equatable::equals(). This is so because in certain cases these methods can be used together in a complementary way to achieve specific results. For example, some structures, such as sets and maps, may use the methods PhpCommon\Comparison\Equatable::equals() and PhpCommon\Comparison\Comparable::compareTo() as part of the strategy to determine where to store or retrieve data. In that way, such inconsistency may lead to unwanted results.

It is inspired by the Comparable interface, from Java API.