Property overloading
Each defined property is accessible in multiple ways, if a getter and or setter method has been defined for that given property.
For additional information, please read about Mutators and Accessor, PHP's overloading, and PHP's Array-Access
// Create a new instance of your DTO
$person = new Person();
// Name can be set using normal setter methods
$person->setName('John');
// But you can also just set the property itself
$person->name = 'Jack'; // Will automatically invoke setName()
// And you can also set it, using an array-accessor
$person['name'] = 'Jane'; // Will also automatically invoke setName()
// ... //
// Obtain age using the regular getter method
$age = $person->getAge();
// Can also get it via invoking the property directly
$age = $person->age; // Will automatically invoke getAge()
// Lastly, it can also be access via an array-accessor
$age = $person['age']; // Also invokes the getAge()
Tips
If you are using a modern IDE, then it will most likely support PHPDoc.
By adding a @property tag to your interface or concrete implementation, your IDE will be able to auto-complete the overloadable properties.
Behind the Scene
The Overload component is responsible for handling the properties overloading of the Dto abstraction.