Set the callback used to filter the objects in the underlying collection.
The callback should return true if an object should appear in the filtered collection.
If a null callback is set, then all underlynig objects will appear in the filtered collection.
This will refilter the collection.
| this |
a filter collection |
| callback |
function to call for each object |
| destroy_func |
called for user_data when it is no longer needed |
| user_data |
data to pass to the callback |