findDiffs.cfc

<cfscript>
// our pretend version of the pests that we input by a user
pests = [5,6,10];

rev = EntityLoadByPK("Revisions",1);

// get the id of all matching pests
ormPests = JavaCast("string[]",ormExecuteQuery("select Pest.Code from RevisionPests where Revision.Id=?",[rev.getId()]));
dbPests = ArrayNew(1);
for( i=1; i<=ArrayLen(ormPests); i++){
    ArrayAppend(dbPests,javaCast("string",ormPests[i]));
}

// find matching
matching = createObject("java", "java.util.HashSet").init(dbPests);
matching.retainAll(pests);

// what needs to be removed?
toRemove = createObject("java", "java.util.HashSet").init(dbPests);
toRemove.removeAll(matching);

// what needs to be added?
toAdd = createObject("java", "java.util.HashSet").init(pests);
toAdd.removeAll(matching);

WriteDump(toRemove.toArray());
WriteDump(toAdd.toArray());

</cfscript>