Resizable-array implementation of the
Deque interface. Array
deques have no capacity restrictions; they grow as necessary to support
usage. They are not thread-safe; in the absence of external
synchronization, they do not support concurrent access by multiple threads.
Null elements are prohibited. This class is likely to be faster than
Stack when used as a stack, and faster than
when used as a queue.
ArrayDeque operations run in amortized constant time.
and the bulk operations, all of which run in linear time.
The iterators returned by this class's
method are fail-fast: If the deque is modified at any time after
the iterator is created, in any way except through the iterator's own
remove method, the iterator will generally throw a
ConcurrentModificationException. Thus, in the face of concurrent
modification, the iterator fails quickly and cleanly, rather than risking
arbitrary, non-deterministic behavior at an undetermined time in the
Note that the fail-fast behavior of an iterator cannot be guaranteed
as it is, generally speaking, impossible to make any hard guarantees in the
presence of unsynchronized concurrent modification. Fail-fast iterators
ConcurrentModificationException on a best-effort basis.
Therefore, it would be wrong to write a program that depended on this
exception for its correctness: the fail-fast behavior of iterators
should be used only to detect bugs.
Public Constructor Summary
Constructs an empty array deque with an initial capacity sufficient to hold 16 elements.
Constructs an empty array deque with an initial capacity sufficient to hold the specified number of elements.
Public Method Summary
Inserts the specified element at the end of this deque.