Hello, 2013/11/17 Stanislas Nanchen <stanislas.nanc...@gmail.com>
> Hello, > > I want to load Records in Trees/Graphs to navigate them, and of course, i > want to manipulate them (and change them) after loading. > I confused "identity" and "value" by using Records directly in the > graph/tree/set. Because they implement hashCode and equals, Records are > really > only the "values" that certain entities have in the database. What I want > to put in the graph/tree are these entities themselves. Jooq has > no "reference" type for that. > Aha, yes, I can see your concern, now. There had been a couple of discussions in the past, related to Record value vs. Record identity. These discussions were mostly initiated by Joachim Durchholz, e.g. in these threads: - https://groups.google.com/d/msg/jooq-user/NAOpCatRcjs/KMrV_Zu_S28J - https://groups.google.com/d/msg/jooq-user/SAGC0FZtJrs/fkmN4INYQhQJ jOOQ's Records implement equals() and hashCode() in a way that matches SQL's row value expressions. This has been complemented in jOOQ 3.0, when Record also implemented Comparable<Record>: https://github.com/jOOQ/jOOQ/issues/2107 Actually, Records have some attributes of "identities" (they know if they > need to insert or update); yet I cannot use them as "entities" because > after changing they are no more equals to themselves, (their hash code > changes). > > What i would really like are immutable Records to hold "values" and some > reference types to hold "identities". > > In any case, thanks for the help! I will use some reference types to make > it work. > OK, fair enough Note that using jOOQ 3.2, you can easily add custom code sections to generated code, including generated records (I've noticed that this isn't yet documented appropriately in the manual): https://github.com/jOOQ/jOOQ/issues/2713 This would allow you to override equals() and hashCode() behaviour to use only primary key values for equals() and hashCode() evaluation. If that's too risky (it probably is), you might consider providing an external equals and hashCode provider to the Set. It's a generally interesting topic. I haven't found such a thing in Guava after a short search, but there's a possibility of implementing org.apache.commons.collections.map.AbstractHashedMap In that class, you can just override the protected hash(), isEqualKey(), isEqualValue(), and createEntry() methods. Here's a related Stack Overflow question: http://stackoverflow.com/a/20030782/521799 Cheers Lukas -- You received this message because you are subscribed to the Google Groups "jOOQ User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to jooq-user+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
