Sort a list based on URL parameter (or sort nested domain model in query) - list

Question

I'm sure there is a way to do this, but I'm really stuck on this one.
I have a domain model that connects to entities Foo and Bar in a many-to-many-relationship. Now when I want to list all Foos to a certain Bar, I do the query and get a lot of FooBar objects. I iterate through these objects and add all Foos to a list.
Like so:
def fooBarRelations = FooBar.findAllByBar bar
def fooList = []
fooBarRelations.each { fooList.add it.foo }
How can I sort the fooList based upon the parameters a g:sortableColumn adds to the url namely sort (the field to sort) and order.
I know you can pass the parameters to the query directly but I think this is not possible in my case?
So how can I either
Make one query without list iterating so I can pass in the sorting parameters OR
Sort my custom list based upon the sorting parameters?
Addition 1 (03/25/2012)
If I could to this ...
def fooBarRelations = FooBar.findAllByBar bar, [sort: 'foo.' + params.sort, order: params.order]
... the problem would be solved. But passing this to the query does not have any effect on the output. Is there any way I can sort a query by a sub-property?

Answer 1

If you really can't sort within the query itself. Then you need a list of lists.
List<List<Fields>> mylist;// where List<Fields> is a lists of the fields.
Then use a Comparator to sort your List> by the desired filed. Say your desired field is at index 3:
new Compare(List<Fields> L1, List<Fields> L2){
if(L1.get(3)>L2.get(3))
return -1;//etc.
UPATE BASED ON COMMENT:
say your entity is as follows
public class Entity{
String name, address, school;
Integer bankaccount;
//etc...
}
Then
public class WhereISort{
List<Entity> myList;
String mysorter;//mysorter can be declared here as static final
public WhereISort(){//maybe pass list in here or whatever
}
public Response myWebService(params..., String sorter){
mysorter=sorter;//mysorter can be declared here as static final
Collections.sort(myList, new Comparator() {
public int compare(Entity e1, Entity e2) {
if(mysorter.equalsIgnoreCase("name")){
return e1.getName().compareToIgnoreCase(e1.getName());
}else if(mysorter.equalsIgnoreCase("bankaccount")){
//your code here, etc.
}
}
});
}
}
Of course, the main point is using "mysorter" and the inner class "Comparator" to sort