Grady Booch in Object-Oriented Analysis and Design with Applications says:
The state of an object encompasses all of the (usually static) properties of the object plus the current (usually dynamic) values of each of these properties ...
Another property of a vending machine is that it can accept money. This is a static (i.e., fixed) property, meaning that it is an essential characteristic of a vending machine.
All properties have some value. This value might be a simple quantity, or it might denote another object.
I am in doubt in about "
the ability of accepting money" is a real property. Instead it seems it describes a behavior. Also Grady Booch says "All properties have some value."; but what is the value of "
the ability of accepting money"?