Getters And Setters


Getters return the value of a property. They may also make a small modification of the returned result.

Let's look the following example:


Members that have __ prefix are meant to be accessed only inside the class body.

If we need to access it outside the class body a getter needs to be defined.

Basically get_side accesses the private member __side.

Accessing a private member (__side in this case) won't throw exception but it's a good coding convention private members to be accessed only inside the class body.


Setters allow for a property to be modified. They are important since they can provide validation before a value is set.

Together getters and setters can control access and modification of a class member.

Let's look at the following example:



  • __age is a private member (because it has __ prefix) so it's supposed to be accessed / modified via it's getters and setters.
  • For obj1 a value of 20 is set for the __age property via it's setter - set_age.
  • For obj2 a value of -10 is attempted to be set for the __age property. Due to the validation at line 6 a value of 0 is set.

Why using getters and setters?

Because private members can have validation before modification (setter) and controlled access (getter).

It seems easier to have only public members (without __ prefix). This way there is no need for getters and setters. It's a better practice to have private members that are accessed with getter and modified through setter. This way a validation can be provided in a setter and the public access can be done only to some members - those which have getters.