Grails mapping sort on multiple fields :: Groovy sort on multiple map entries

Question

Stumped on this one. In Grails it seems one cannot define a default sort on multiple columns in domain mapping a la static mapping = { sort 'prop1 desc, prop2 asc' }, or { sort([prop1:'desc', prop2:'asc']) }. Only first column gets sorted, lame.

Similarly, when trying to Groovy sort a Grails findAllBy query on multiple columns, the second sort overrides the first.

def list = [[rowNum:2,position:3],[rowNum:1,position:2],[rowNum:3,position:1]]

list.sort{it.rowNum}.sort{it.position}

Obviously missing the boat on the latter case, the groovy sort. I have seen postings re: implementing comparable, but looking for something more concise if possible.

Solution 1

Here is a Groovy solution. Still essentially implementing a Comparator though.

list.sort { map1, map2 -> map1.rowNum <=> map2.rowNum ?: map1.position <=> map2.position }

Solution 2

Thanks to the link from GreenGiant, we see that the issue is closed as fixed as of version 2.3.

There is also example code:

static mapping =
    { sort([lastname:'asc', name:'asc']) }

It is working for me in 2.4.3

Comments

[virtualeyes]

just saw have not tested in console -- this will achieve same as HQL find("from SomeDomain as s order by rowNum asc, position desc")?

[virtualeyes]

Tasty ;--) confirmed it works; 1-liner is perfectly fine. Would be nice if we could do at mapping level in grails, but that may have to wait for 1.4 and new hibernate. Thanks Peter!

[wrschneider]

Combinatino of spaceship and Elvis operators makes it super-clean

[IgniteCoders]

@virtualeyes this doesn't sort like HQL, you need to find the collection by your self, and then use sort on it

[virtualeyes]

Thanks, I left Grails not long after posting (4 years ago), might help others though ;-)