Queue.offer()
Adds an element to the tail of a queue.
Available since: Java 1.5
Syntax
boolean offer(E e)Parameters
| Parameter | Type | Description |
|---|---|---|
| e | E | The element to add. |
Return value
boolean`true` if the element was added; `false` if a bounded queue is full.
Examples
Adding to a queue:
void main() {
Queue<Integer> jobs = new ArrayDeque<>();
jobs.offer(10);
jobs.offer(20);
IO.println(jobs);
}Output:
[10, 20]Notes
For ordinary queues offer() and add() behave the same. The difference shows in bounded queues (for example ArrayBlockingQueue): add() throws IllegalStateException, while offer() returns false. ArrayDeque does not accept null.
See also
- Queue.poll() — Takes and removes the head of a queue.
- Queue.peek() — Returns the head of a queue without removing it.
- Queue — A queue: elements are added at the tail and taken from the head.
In the tutorial
- Queues and deques — Queues in Java: Queue and ArrayDeque, a stack built on Deque, the offer, poll and peek methods and the PriorityQueue.