An unbounded blocking queue of
Delayed elements, in which an element can only be taken
when its delay has expired. The head of the queue is that
Delayed element whose delay expired furthest in the
past. If no delay has expired there is no head and
null. Expiration occurs when an element's
getDelay(TimeUnit.NANOSECONDS) method returns a value less
than or equal to zero. Even though unexpired elements cannot be
poll, they are otherwise
treated as normal elements. For example, the
returns the count of both expired and unexpired elements.
This queue does not permit null elements.
This class and its iterator implement all of the
optional methods of the
Iterator interfaces. The Iterator provided in method
iterator() is not guaranteed to traverse the elements of
the DelayQueue in any particular order.
This class is a member of the Java Collections Framework.
|the type of elements held in this collection|