This class provides skeletal implementations of some
Queue
operations. The implementations in this class are appropriate when the base implementation does
not allow
null
elements. Methods
add
,
remove
, and
element
are based on
offer
,
poll
, and
peek
, respectively, but throw exceptions instead of indicating failure via
false
or
null
returns.
A Queue
implementation that extends this class must minimally define a method Queue.offer(E)
which does not permit insertion of null
elements, along with methods Queue.peek()
, Queue.poll()
, Collection.size()
, and Collection.iterator()
. Typically, additional methods will be overridden as well. If these requirements cannot be met, consider instead subclassing AbstractCollection
.
This class is a member of the Java Collections Framework .