public class ObjectArrayFIFOQueue<K> extends AbstractPriorityQueue<K> implements Serializable
Instances of this class represent a FIFO queue using a backing
array in a circular way. The array is enlarged and shrunk as needed. You can use the trim()
method
to reduce its memory usage, if necessary.
This class provides additional methods that implement a deque (double-ended queue).
Modifier and Type | Field and Description |
---|---|
static int |
INITIAL_CAPACITY
The standard initial capacity of a queue.
|
Constructor and Description |
---|
ObjectArrayFIFOQueue()
Creates a new empty queue with standard initial capacity.
|
ObjectArrayFIFOQueue(int capacity)
Creates a new empty queue with given capacity.
|
Modifier and Type | Method and Description |
---|---|
void |
clear()
Removes all elements from this queue.
|
Comparator<? super K> |
comparator()
Returns
null (FIFO queues have no comparator). |
K |
dequeue()
Dequeues the first element from the queue.
|
K |
dequeueLast()
Dequeues the last element from the queue.
|
void |
enqueue(K x)
Enqueues a new element.
|
void |
enqueueFirst(K x)
Enqueues a new element as the first element (in dequeuing order) of the queue.
|
K |
first()
Returns the first element of the queue.
|
K |
last()
Returns the last element of the queue.
|
int |
size()
Returns the number of elements in this queue.
|
void |
trim()
Trims the queue to the smallest possible size.
|
changed, isEmpty
public static final int INITIAL_CAPACITY
public ObjectArrayFIFOQueue(int capacity)
capacity
- the initial capacity of this queue.public ObjectArrayFIFOQueue()
public Comparator<? super K> comparator()
null
(FIFO queues have no comparator).comparator
in interface PriorityQueue<K>
null
.public K dequeue()
PriorityQueue
dequeue
in interface PriorityQueue<K>
public K dequeueLast()
NoSuchElementException
- if the queue is empty.public void enqueue(K x)
PriorityQueue
enqueue
in interface PriorityQueue<K>
x
- the element to enqueue..public void enqueueFirst(K x)
public K first()
first
in interface PriorityQueue<K>
public K last()
last
in interface PriorityQueue<K>
last
in class AbstractPriorityQueue<K>
public void clear()
PriorityQueue
clear
in interface PriorityQueue<K>
public void trim()
public int size()
PriorityQueue
size
in interface PriorityQueue<K>