Internally it holds the items in the $_data array, the same as most Interfaces
and
Traits
of this package.
Typed Datastructures
All datastructures in this package have in common that you can control the types of items they can hold.
To restrict allowed data types for items, provide the constructor with an array of atomic types or fully qualified
class names you want to allow as item types. Available atomic types are array, bool, callable, countable,
float / double, int / integer / long, iterable, null, numeric, object, resource, scalar and
string.
Trying to add an item with a data type not on the list of allowed types to a strict datastructure will result in an InvalidDataTypeException .
Examples:
// create a collection of strings $stringCollection = new StrictCollection(['string']); // create a queue of PSR-15 middlewares $middlewareQueue = new StrictQueue(['Psr\Http\Server\MiddlewareInterface']);
StrictCollection
A type-sensitive, unsorted collection of items.
Holds items as key/value pairs where keys identify the items and have to be valid array keys while values can be of any controlled type.
A StrictCollection can be accessed like an array, but not traversed because it has no particular order. Technically
speaking, StrictCollection implements \ArrayAccess, \Countable and \Serializable, but no \Traversable interface.
StrictList
A type-sensitive, taversable list of items.
Extends \SplDoublyLinkedList with an option to restrict the allowed data types for list items.
StrictQueue
A type-sensitive, taversable queue (FIFO) of items.
Extends \SplDoublyLinkedList with an option to restrict the allowed data types for list items.
StrictStack
A type-sensitive, taversable stack (LIFO) of items.
Extends \SplDoublyLinkedList with an option to restrict the allowed data types for list items.