klasseninvariant

Klasseninvariant refers to a property that remains unchanged for all objects of a given class. In object-oriented programming, this concept is crucial for ensuring the integrity and predictability of a class's behavior. A klasseninvariant is a condition that must always be true for any instance of a class, both before and after any public method of that class is executed. It acts as a contract between the class designer and its users, guaranteeing that certain invariants will be maintained.

Developers establish klasseninvariants to define the valid states an object can be in. For example, in a class representing a bank account, a klasseninvariant might be that the account balance can never be negative. Methods that modify the object's state, such as depositing or withdrawing funds, must be designed in a way that preserves this invariant. If a method violates a klasseninvariant, it indicates a bug in the implementation.

The use of klasseninvariants aids in reasoning about code, debugging, and formal verification. By stating and enforcing these invariants, developers can create more robust and reliable software. They help in understanding the intended behavior of a class and can be used by testing frameworks to automatically check for violations. The concept is closely related to the principle of encapsulation, as invariants are typically internal to the class and not directly accessible or modifiable from outside.