This file describes the classes of this package. All interfaces can be combined. Don't panic, the interfaces are quite easy and the ConfigurationTrait, which is a concrete implementation, has full support of those interfaces. You need only one interface called RequiresConfig to start and then you can implement the others if they are needed.

  • RequiresConfig Interface
  • RequiresConfigId Interface
  • RequiresMandatoryOptions Interface
  • ProvidesDefaultOptions Interface

RequiresConfig Interface

The RequiresConfig interface exposes three methods: dimensions, canRetrieveOptions and options.


    public function dimensions() : iterable

The dimensions method has no parameters and MUST return an array. The values (used as key names) of the array are used as the depth of the configuration to retrieve options. Two values means a configuration depth of two. An empty array is valid.


    public function canRetrieveOptions($config) : bool

Checks if options are available depending on provided dimensions and checks that the retrieved options are an array or have implemented \ArrayAccess.


    public function options($config) : []

The options method takes one mandatory parameter: a configuration array. It MUST be an array or an object which implements the ArrayAccess interface. A call to options returns the configuration depending on provided dimensions of the class or throws an exception if the parameter is invalid or if the configuration is missing or if a mandatory option is missing.

If the ProvidesDefaultOptions interface is implemented, these options MUST be overridden by the provided config.


Exceptions directly thrown by the options method MUST implement the Interop\Config\Exception\ExceptionInterface.

If the configuration parameter is not an array or not an object which implements the ArrayAccess interface the method SHOULD throw a Interop\Config\Exception\InvalidArgumentException.

If a key which is returned from dimensions is not set under the previous dimensions key in the configuration parameter, the method SHOULD throw a Interop\Config\Exception\OptionNotFoundException.

If a value from the configuration based on dimensions is not an array or an object which has \ArrayAccess implemented, the method SHOULD throw a Interop\Config\Exception\UnexpectedValueException.

If the class implements the RequiresMandatoryOptions interface and if a mandatory option from mandatoryOptions is not set in the options array which was retrieved from the configuration parameter before, the method SHOULD throw a Interop\Config\Exception\MandatoryOptionNotFoundException.

If the retrieved options are not of type array or \ArrayAccess the method SHOULD throw a Interop\Config\Exception\UnexpectedValueException.

RequiresMandatoryOptions Interface

The RequiresMandatoryOptions interface exposes one method: mandatoryOptions


    public function mandatoryOptions() : iterable

The mandatoryOptions method has no parameters and MUST return an array of strings which represents the list of mandatory options. This array can have a multiple depth.

ProvidesDefaultOptions Interface

The DefaultOptions interface exposes one method: defaultOptions


    public function defaultOptions() : iterable

The defaultOptions method has no parameters and MUST return an key-value array where the key is the option name and the value is the default value for this option. This array can have a multiple depth. The return value MUST be compatible with the PHP function array_replace_recursive.


The RequiresConfigId is only a marker interface and has no methods. It marks the factory that multiple instances are supported. The ConfigurationTrait has an optional parameter $configId implemented for the methods of RequiresConfig. So it is full supported.


The ConfigurationTrait implements the functions of RequiresConfig interface and has support for ProvidesDefaultOptions, RequiresMandatoryOptions and RequiresConfigId interfaces if the the class has they implemented.

Additional it has one more method optionsWithFallback to reduce boilerplate code.


    public function optionsWithFallback($config) : []

Checks if options can be retrieved from config and if not, default options (ProvidesDefaultOptions interface) or an empty array will be returned.