An example model with RAVE validation.

ExampleModel.java

@Validated(factory = RaveValidatorFactory.class)
public class MyModel {

    @NonNull private String someString;

    public MyModel(@NonNull String someString) {
        this.someString = someString;
    }

    @NonNull
    public String getSomeString() {
        return someString;
    }

    @MustBeTrue
    public boolean customValidationLogic() {
        if (someString.contains("!")) {
            return someString.charAt(someString.length() - 1) == '!'; 
        }
        return true;
    }
}