Can I append a closure to another in Groovy?

I have two very similar methods in Grails, something like "calculate statistics by os" and "calculate statistics by browser" - effectively both prepare some things, then run a similar query on the DB, then do things with the results. The only part where the methods differ is the query they run in the middle of my method -

def summary = c.list {
    eq('browser', Browser.get(1)) // OR eq('os', OS.get(1))
    between('date', dates.start, dates.end)
}

It occurred to me that the ideal way to refactor it would be to pass in the first line of the closure as a method parameter. Like

doStats (Closure query) {
    ...
    def summary = c.list {
        query
        between('date', dates.start, dates.end)
    }
}

I tried this but "query" gets ignored. I tried query() instead but then the query clause is executed where defined, so this doesn't work either. I suppose I could just pass the whole closure as a parameter but that seems wrong - the query might also get more complicated in future.

Anyone have any better ideas?

Solution

You're using the criteria DSL which might be different than plain groovy closures.

To do what you're asking, you can use the method described here -

http://mrhaki.blogspot.com/2010/06/grails-goodness-refactoring-criteria.html

and put your query in to private method.

The more elegant solution for this is to use named queries in grails -

http://grails.org/doc/latest/ref/Domain%20Classes/namedQueries.html

Look at the

  recentPublicationsWithBookInTitle {
       // calls to other named queries…
       recentPublications()
       publicationsWithBookInTitle()
  }

example -