public class ObjectArrayPriorityQueue<K> extends java.lang.Object implements PriorityQueue<K>, java.io.Serializable
Instances of this class represent a priority queue using a backing
array—all operations are performed directly on the array. The array is
enlarged as needed, but it is never shrunk. Use the trim()
method
to reduce its size, if necessary.
Constructor and Description |
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ObjectArrayPriorityQueue()
Creates a new empty queue using the natural order.
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ObjectArrayPriorityQueue(java.util.Comparator<? super K> c)
Creates a new empty queue with a given comparator.
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ObjectArrayPriorityQueue(int capacity)
Creates a new empty queue with a given capacity and using the natural order.
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ObjectArrayPriorityQueue(int capacity,
java.util.Comparator<? super K> c)
Creates a new empty queue with a given capacity and comparator.
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ObjectArrayPriorityQueue(K[] a)
Wraps a given array in a queue using the natural order.
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ObjectArrayPriorityQueue(K[] a,
java.util.Comparator<? super K> c)
Wraps a given array in a queue using a given comparator.
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ObjectArrayPriorityQueue(K[] a,
int size)
Wraps a given array in a queue using the natural order.
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ObjectArrayPriorityQueue(K[] a,
int size,
java.util.Comparator<? super K> c)
Wraps a given array in a queue using a given comparator.
|
Modifier and Type | Method and Description |
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void |
changed()
Notifies the queue that the first element has changed (optional operation).
|
void |
clear()
Removes all elements from this queue.
|
java.util.Comparator<? super K> |
comparator()
Returns the comparator associated with this queue, or
null if it uses its elements' natural ordering. |
K |
dequeue()
Dequeues the first element from the queue.
|
void |
enqueue(K x)
Enqueues a new element.
|
K |
first()
Returns the first element of the queue.
|
int |
size()
Returns the number of elements in this queue.
|
void |
trim()
Trims the underlying array so that it has exactly
size() elements. |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
isEmpty, last
public ObjectArrayPriorityQueue(int capacity, java.util.Comparator<? super K> c)
capacity
- the initial capacity of this queue.c
- the comparator used in this queue, or null
for the natural order.public ObjectArrayPriorityQueue(int capacity)
capacity
- the initial capacity of this queue.public ObjectArrayPriorityQueue(java.util.Comparator<? super K> c)
c
- the comparator used in this queue, or null
for the natural order.public ObjectArrayPriorityQueue()
public ObjectArrayPriorityQueue(K[] a, int size, java.util.Comparator<? super K> c)
The queue returned by this method will be backed by the given array.
a
- an array.size
- the number of elements to be included in the queue.c
- the comparator used in this queue, or null
for the natural order.public ObjectArrayPriorityQueue(K[] a, java.util.Comparator<? super K> c)
The queue returned by this method will be backed by the given array.
a
- an array.c
- the comparator used in this queue, or null
for the natural order.public ObjectArrayPriorityQueue(K[] a, int size)
The queue returned by this method will be backed by the given array.
a
- an array.size
- the number of elements to be included in the queue.public ObjectArrayPriorityQueue(K[] a)
The queue returned by this method will be backed by the given array.
a
- an array.public void enqueue(K x)
PriorityQueue
enqueue
in interface PriorityQueue<K>
x
- the element to enqueue.public K dequeue()
PriorityQueue
dequeue
in interface PriorityQueue<K>
public K first()
PriorityQueue
first
in interface PriorityQueue<K>
public void changed()
PriorityQueue
This default implementation just throws an UnsupportedOperationException
.
changed
in interface PriorityQueue<K>
public int size()
PriorityQueue
size
in interface PriorityQueue<K>
public void clear()
PriorityQueue
clear
in interface PriorityQueue<K>
public void trim()
size()
elements.public java.util.Comparator<? super K> comparator()
PriorityQueue
null
if it uses its elements' natural ordering.comparator
in interface PriorityQueue<K>
null
if it uses its elements' natural ordering.