Didn't find rule 'classes should not be final'

[ghusta]

I didn't find a rule to assert that classes should (or not) be final.

For example I'd like to do this :

        ArchRule rule = classes()
                .that().areAnnotatedWith(Entity.class)
                .should().notBeFinal();

I was just able to add a custom ArchCondition like :

    static ArchCondition<JavaClass> beFinal = new ArchCondition<>("be final") {
        @Override
        public void check(JavaClass javaClass, ConditionEvents events) {
            boolean isFinal = javaClass.getModifiers().contains(JavaModifier.FINAL);
            if (!isFinal) {
                String message = String.format("%s is not final", javaClass.getName());
                events.add(SimpleConditionEvent.violated(javaClass, message));
            }
        }
    };

    static ArchCondition<JavaClass> notBeFinal = new ArchCondition<>("not be final") {
        @Override
        public void check(JavaClass javaClass, ConditionEvents events) {
            boolean isFinal = javaClass.getModifiers().contains(JavaModifier.FINAL);
            if (isFinal) {
                String message = String.format("%s is final", javaClass.getName());
                events.add(SimpleConditionEvent.violated(javaClass, message));
            }
        }
    };

[hankem]

You can use .should().notHaveModifier(JavaModifier modifier):

    ArchRule rule = classes()
            .that().areAnnotatedWith(Entity.class)
            .should().notHaveModifier(JavaModifier.FINAL);

[ghusta]

Thank you !
Good to know there is something shorter to write.

At first I was looking for methods similar to bePublic() or bePrivate(), but was suprised to not find beFinal()...

[hankem]

bePublic() and bePrivate() had been added more than 7 years ago (f03e630); I guess the focus back then was more on supporting the most relevant architectural use cases. I think that beFinal() is more for a coding convention or implementation use case. But I agree, it could be added to the fluent API.

Just one more remark on shorter implementations:

For ArchConditions that essentially check a predicate, you can use ArchConditions.be or ArchConditions.have.

If there was no predefined method in the fluent API, you could still simplify your conditions using

import static com.tngtech.archunit.base.DescribedPredicate.describe;
import static com.tngtech.archunit.lang.conditions.ArchConditions.be;
import static com.tngtech.archunit.lang.conditions.ArchConditions.not;

to

ArchCondition<JavaClass> beFinal = be(describe("final", javaClass ->
        javaClass.getModifiers().contains(JavaModifier.FINAL))
);

ArchCondition<JavaClass> notBeFinal = not(beFinal);

[ghusta]

Thank you for your clarifications.

Using a predicate is indeed shorter and more elegant 👍