boolean function ( ) { return depth ( ) == 0 ; }
returns true if the queue is empty , otherwise false concode_field_sep AtomicReference<T>[] circularArray concode_elem_sep int maxSize concode_elem_sep AtomicLong currentIndex concode_field_sep int depth concode_elem_sep int getIndex concode_elem_sep T[] toArray concode_elem_sep int getCurrentIndex concode_elem_sep void push concode_elem_sep T peek