In the Java code generated from Rune, it is not possible to validate the inputs to a function.

However, it is possible to validate the output of a function. In the generated function code, a ModelObjectValidator is injected (via Guice) which can be configured with different implementations, e.g., it can validate the output object and throw an exception if the output object is invalid. For performance reasons, the default Guice implementation used for functions is a no-op validator.

The Java code generators should be updated so the functions inputs are validated in the same configurable way as the output.