Add support for self (left / right / inner / cross) join #292

Spike2050 · 2017-03-05T00:00:12Z

Changes as discussed in issue #290.

Has (passing) tests and added description in readme.md.

I also adjusted some comments from the other joins.

…Join + Tests + Comments + Readme

lukaseder

Thanks a lot for your suggestion. I've commented on a couple of issues. Let me know what you think.

lukaseder · 2017-03-05T09:35:28Z

README.md

@@ -62,6 +65,9 @@ Seq.of(1, 2, 3, 4).grouped(i -> i % 2);
 // (tuple(1, 1), tuple(2, 2))
 Seq.of(1, 2, 4).innerJoin(Seq.of(1, 2, 3), (a, b) -> a == b);

+// (tuple(1, 1), tuple(2, 2))
+Seq.of(1, 2).innerSelfJoin((t, u) -> t == u)


Hmm, this would be a rather inefficient alternative to:

Seq.of(1, 2).map(i -> tuple(i, i))

Perhaps, a more convincing example might be interesting here, similar to your outer join examples, where child / parent relationships are joined. What do you think?

Ill just change that to

// (tuple(1, 2), tuple(2, 1)) Seq.of(1, 2).innerSelfJoin((t, u) -> t != u)

Yeah, nice thinking. That's a common use-case in SQL too

lukaseder · 2017-03-05T09:36:54Z

README.md

@@ -77,6 +83,9 @@ Seq.of(1, 2, 3).join("|", "^", "$");
 // (tuple(1, 1), tuple(2, 2), tuple(4, null))
 Seq.of(1, 2, 4).leftOuterJoin(Seq.of(1, 2, 3), (a, b) -> a == b);

+// (tuple(tuple(1, 0), NULL), tuple(tuple(2, 1), tuple(1, 0)))
+Seq.of(new Tuple2<Integer, Integer>(1, 0), new Tuple2<Integer, Integer>(2, 1)).leftOuterSelfJoin((t, u) -> t.v2 == u.v1)


For brevity's sake, we can replace the constructor call with the Tuple.tuple() convenience method and assume a static import, so:

Seq.of(tuple(1, 0), tuple(2, 1))...

lukaseder · 2017-03-05T09:38:34Z

src/main/java/org/jooq/lambda/Seq.java

     * Inner join 2 streams into one.
     * <p>
     * <code><pre>
     * // (tuple(1, 1), tuple(2, 2))
-     * Seq.of(1, 2, 3).innerJoin(Seq.of(1, 2), t -> Objects.equals(t.v1, t.v2))
+     * Seq.of(1, 2, 3).innerJoin(Seq.of(1, 2), (t, u) -> Objects.equals(t, u))


Thanks for these. Would you mind fixing these in a separate pull request, as they're not strictly related to this particular change...

lukaseder · 2017-03-05T09:40:36Z

src/main/java/org/jooq/lambda/Seq.java

+        return seq(list).flatMap(t -> seq(list)
+                                     .filter(u -> predicate.test(t, u))
+                                     .map(u -> tuple(t, u)));
+    }


Hmm, I wonder if we perhaps would be better off if this method delegates to the existing innerJoin() method, and we start optimising these joins in a different task...

Well I could just do this

default Seq<Tuple2<T, T>> innerSelfJoin(BiPredicate<? super T, ? super T> predicate) { // This algorithm isn't lazy and has substantial complexity for large argument streams! List<? extends T> list = toList(); return seq(list).innerJoin(seq(list), predicate); }

Even better

lukaseder · 2017-03-05T09:41:47Z

src/main/java/org/jooq/lambda/Seq.java

+                           .onEmpty(null)
+                           .map(u -> tuple(t, u)))
+                           .onClose(other::close);
+    }


Thanks for fixing the formatting. Perhaps, this could be done in a separate task as well. In particular, now, the onClose() method is not aligned correctly according to your fix's intention.

lukaseder · 2017-03-05T09:41:48Z

src/main/java/org/jooq/lambda/Seq.java

+                           .onEmpty(null)
+                           .map(u -> tuple(t, u)))
+                           .onClose(other::close);
+    }


Thanks for fixing the formatting. Perhaps, this could be done in a separate task as well. In particular, now, the onClose() method is not aligned correctly according to your fix's intention.

Spike2050 · 2017-03-05T10:47:35Z

I made another pull request with just the comments and idents

Spike2050 · 2017-03-05T19:03:17Z

I incorporated the discussed changes, you can check it again.

lukaseder · 2017-03-06T14:58:59Z

That looks great, thank you very much again for your contribution!

Spike2050 · 2017-03-06T18:37:25Z

Pleasure

When do you plan your next release?

lukaseder · 2017-03-06T18:42:47Z

I guess we have enough new things. Will look into it these days

Spike2050 · 2017-03-07T12:15:45Z

Ever thought about doing an official Snapshot/Nightly/Alpha?

I mean I did install a private one on my nexus, to test the selfjoins with my other projects, but an official one would be nice.

lukaseder · 2017-03-07T12:48:06Z

If there's something OOTB that does this on Github with absolutely no manual work involved, sure. Do you know any?

Spike2050 · 2017-03-07T13:17:20Z

Well I work with Jenkins, which does this for me, but I think Travis can do that too.

I found this link which descripes a Travis Setup to deploy to Maven, including SNAPSHOT-version. But as I see it you might need to hide your Travis configuration from public Github repo, because it would store your Maven repo login. It might be what you need.

billoneil · 2017-03-07T13:25:11Z

I don't know if its worth publishing snapshots to maven. If you really want to allow users to use unreleased versions, a very little effort solution could be jitpack. You grant them access to the repo. It clones the repo and builds the code from a tag / branch / git hash in a docker container on the fly and serves the produced Jar. It works with maven and gradle if you add them as a repository. https://jitpack.io/docs/#building-with-jitpack

…

On Tue, Mar 7, 2017 at 8:17 AM, Spike2050 ***@***.***> wrote: Well I work with Jenkins, which does this for me, but I think Travis can do that too. I found this link <https://coderwall.com/p/9b_lfq/deploying-maven-artifacts-from-travis> which descripes a Travis Setup to deploy to Maven, including SNAPSHOT-version. But as I see it you might need to hide your Travis configuration from public Github repo, because it would store your Maven repo login — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#292 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AE9tUg17iylBf6IcNIGY4XoNwYuOkfwtks5rjVjhgaJpZM4MTQbw> .

lukaseder · 2017-03-07T13:44:14Z

Hmm, yes, I could use the jOOQ CI server (Jenkins) to deploy nightlies to Maven Central... But that's already too much effort, given the relatively little progress this library makes between releases :)

And Jitpack sounds nice, but another infrastructure dependency to look after.

I'll wait with this, until more users request it (also for the other jOO* libraries).

Spike2050 · 2017-11-13T11:32:53Z

Hey lukaseder.

What ever came of the realease you were looking into?

Greets

lukaseder · 2017-11-13T12:04:59Z

I'm sorry - not sure if I understand, what are you asking me, @Spike2050 ?

bendem · 2017-11-15T08:52:08Z

When do you plan your next release?

I guess we have enough new things. Will look into it these days

I think he's speaking about the fact that the last release you did was more than a year ago and that there are a bunch of new stuff to release now (I'd totally be interested in a new release as well) :).

Spike2050 · 2017-11-16T14:01:22Z

I think he's speaking about the fact that the last release you did was more than a year ago and that there are a bunch of new stuff to release now (I'd totally be interested in a new release as well) :).

Well that :-)

Added crossSelfJoin, innerSelfJoin, leftOuterSelfJoin, rightOuterSelf…

35e51f4

…Join + Tests + Comments + Readme

lukaseder added P: Medium T: Enhancement labels Mar 5, 2017

lukaseder added this to the Version 0.9.13 milestone Mar 5, 2017

lukaseder requested changes Mar 5, 2017

View reviewed changes

Florian Grißmer added 2 commits March 5, 2017 19:43

Merge branch 'master' into selfjoins

ec9564a

Changes as discussed in #292

0e99c94

lukaseder merged commit 50469cf into jOOQ:master Mar 6, 2017

lukaseder added the R: Fixed label Mar 6, 2017

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Add support for self (left / right / inner / cross) join #292

Add support for self (left / right / inner / cross) join #292

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Add support for self (left / right / inner / cross) join #292

Add support for self (left / right / inner / cross) join #292

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