On 12/19/2011 1:14 PM, Peter Firmstone wrote:
Gregg Wonderly wrote:
On 12/18/2011 11:59 PM, Peter Firmstone wrote:
@Override
public boolean implies(Permission permission) {
if ( ! cl.isInstance(permission)) return false;
Permission [] p = perms.toArray(new Permission[0]); //perms.size()
may change
I not sure why you are using an empty Permission array here, and then looping
over it. Is this from some other testing?
Gregg
The collection is wrapped with a ConcurrentCollection's multi read, single
write wrapper, by passing a zero length array to the collection, it obtains a
read lock, the collection creates a new array, sized to suit the underlying
array, copy's the collection's contents into it and returns, releasing the
read lock, the operation is atomic.
If I did this, the call would acquire and release two read locks
consecutively, it wouldn't be atomic:
Permission[] p = perms.toArray(new Permission[perms.size()]);
It's there to avoid a cast:
Permission [] p = (Permission[]) perms.toArray();
Okay, that make sense from a logic perspective. It might be better to use the
second version just to remove the distraction of trying to understand how a zero
length array results in a non-zero length result.
Your call, I'm not sure it really matters.
Gregg
