Circular Depenency detector Falsely reporting builder pattern about fb-contrib

[ThrawnCA]

That's not how the Builder pattern is supposed to work. User isn't supposed to know about Builder. User should have a constructor that accepts the individual parameters (userId, firstName, lastName), instead of accepting a Builder. (The parameter validation should happen inside User, too.)

The way you have things set up, it's impossible to construct a User directly; you have to create a Builder first. That shouldn't be the case; Builder should just be a convenient shortcut.

So the bug detector is correct.

[mebigfatguy]

Or builder should have a build () method that constructs a user and sets fields on it

[jsotuyod]

Actually, that implementation is perfect. Read Effective Java, 2nd edition, item 2

http://www.google.co.th/url?sa=t&rct=j&q=effective+java&source=web&cd=8&cad=rja&uact=8&ved=0CFQQFjAH&url=http%3A%2F%2Fuet.vnu.edu.vn%2F~chauttm%2Fe-books%2Fjava%2FEffective.Java.2nd.Edition.May.2008.3000th.Release.pdf&ei=V2xmVcWoMsK7uATbmYLwDw&usg=AFQjCNHaTVJ7cBfChZStN4QTEuewWLo98Q

[jsotuyod]

Probably, the best would be to ignore CD when it concerns inner classes (either static or not). After all, being an inner class, they are already tightly coupled and the CD report adds little value.

[christopherpicard]

I agree with Jsotuyod that this check should not apply to inner classes. I am sure there are other cases other than the builder pattern that this check falsely reports.

As far as the other comments about the builder pattern, the whole point of the pattern is to ensure that you always have a fully populated object. It is used a lot when creating immutable objects like this one rather than requiring large number of constructor arguments which is bad practice in both Clean Code and Effective Java.

[mebigfatguy]

anon classes are already not reported. I will extend to all inner classes - that's fine.

Point of note tho, imo, User shouldn't know about the builder class.

public User build() {
     if (userId == null) {
        userId = UUID.randomUUID();
     }
     if (StringUtils.isEmpty(firstName)) {
        throw new IllegalStateException("First name is not set");
     }
     User u new User();
     u.userId = userId;
     u.firstName = firstName;
     u.lastName = lastName;
     return u;
  }

[ThrawnCA]

Well, it's correct that the Builder pattern as implemented matches Effective Java. That's not the same thing as being "perfect". I would still put it to you that it would be better for the constructor to accept individual arguments, and have the Builder provide them all, so that the builder remains an optional part of the process.

But I also agree that it makes sense to drop the CD check for all inner classes.

[jsotuyod]

What is the status of this? Need any help?

[mebigfatguy]

sorry, kind of forgot about this. I thought i had fixed this, and running this class, seems like it is not reported now, so... still broken for you?

[jsotuyod]

Truth be told, I haven't checked. I'm preparing for next week's "week of linting" at the office, trying to come up with a nice colection of things to do on tools such as FindBugs, fb-contrib, PMD, Checkstyle, and our findbugs-plugin and came accross this issue still being open and thought it might be a good fit.

I just checked it and it seems to be gone, so this one could be closed.

If you have anything you think may be interesting for us to help you on, feel free to contact me directly. Thanks!