public class ObjectHeapPriorityQueue<K> extends java.lang.Object implements PriorityQueue<K>, java.io.Serializable
Instances of this class represent a priority queue using a heap. The heap is
enlarged as needed, but it is never shrunk. Use the trim() method to
reduce its size, if necessary.
| Constructor and Description |
|---|
ObjectHeapPriorityQueue()
Creates a new empty queue using the natural order.
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ObjectHeapPriorityQueue(java.util.Collection<? extends K> collection)
Creates a queue using the elements in a collection using the natural order.
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ObjectHeapPriorityQueue(java.util.Collection<? extends K> collection,
java.util.Comparator<? super K> c)
Creates a queue using the elements in a collection using a given comparator.
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ObjectHeapPriorityQueue(java.util.Comparator<? super K> c)
Creates a new empty queue with a given comparator.
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ObjectHeapPriorityQueue(int capacity)
Creates a new empty queue with a given capacity and using the natural order.
|
ObjectHeapPriorityQueue(int capacity,
java.util.Comparator<? super K> c)
Creates a new empty queue with a given capacity and comparator.
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ObjectHeapPriorityQueue(K[] a)
Wraps a given array in a queue using the natural order.
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ObjectHeapPriorityQueue(K[] a,
java.util.Comparator<? super K> c)
Wraps a given array in a queue using a given comparator.
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ObjectHeapPriorityQueue(K[] a,
int size)
Wraps a given array in a queue using the natural order.
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ObjectHeapPriorityQueue(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 |
|---|---|
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 heap array so that it has exactly
size()
elements. |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitisEmpty, lastpublic ObjectHeapPriorityQueue(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 ObjectHeapPriorityQueue(int capacity)
capacity - the initial capacity of this queue.public ObjectHeapPriorityQueue(java.util.Comparator<? super K> c)
c - the comparator used in this queue, or null for the natural
order.public ObjectHeapPriorityQueue()
public ObjectHeapPriorityQueue(K[] a, int size, java.util.Comparator<? super K> c)
The queue returned by this method will be backed by the given array. The
first size element of the array will be rearranged so to form a heap
(this is more efficient than enqueing the elements of a one by one).
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 ObjectHeapPriorityQueue(K[] a, java.util.Comparator<? super K> c)
The queue returned by this method will be backed by the given array. The
elements of the array will be rearranged so to form a heap (this is more
efficient than enqueing the elements of a one by one).
a - an array.c - the comparator used in this queue, or null for the natural
order.public ObjectHeapPriorityQueue(K[] a, int size)
The queue returned by this method will be backed by the given array. The
first size element of the array will be rearranged so to form a heap
(this is more efficient than enqueing the elements of a one by one).
a - an array.size - the number of elements to be included in the queue.public ObjectHeapPriorityQueue(K[] a)
The queue returned by this method will be backed by the given array. The
elements of the array will be rearranged so to form a heap (this is more
efficient than enqueing the elements of a one by one).
a - an array.public ObjectHeapPriorityQueue(java.util.Collection<? extends K> collection, java.util.Comparator<? super K> c)
This constructor is more efficient than enqueing the elements of
collection one by one.
collection - a collection; its elements will be used to initialize the queue.c - the comparator used in this queue, or null for the natural
order.public ObjectHeapPriorityQueue(java.util.Collection<? extends K> collection)
This constructor is more efficient than enqueing the elements of
collection one by one.
collection - a collection; its elements will be used to initialize the queue.public void enqueue(K x)
PriorityQueueenqueue in interface PriorityQueue<K>x - the element to enqueue.public K dequeue()
PriorityQueuedequeue in interface PriorityQueue<K>public K first()
PriorityQueuefirst in interface PriorityQueue<K>public void changed()
PriorityQueueThis default implementation just throws an UnsupportedOperationException.
changed in interface PriorityQueue<K>public int size()
PriorityQueuesize in interface PriorityQueue<K>public void clear()
PriorityQueueclear in interface PriorityQueue<K>public void trim()
size()
elements.public java.util.Comparator<? super K> comparator()
PriorityQueuenull if it uses its elements' natural ordering.comparator in interface PriorityQueue<K>null if it uses its elements' natural ordering.