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| java.util.PriorityQueue
| PriorityQueue | | public class PriorityQueue extends AbstractQueue implements Serializable(Code) | | PriorityQueue holds elements on a priority heap, which orders elements
according to the comparator specified at construction or their natural order.
If the queue uses natural order, any element that is not comparable is not
permitted to insert to the queue.
The least element of the specified ordering is stored at the head of the
queue and the greatest element is stored at the tail of the queue.
PriorityQueue is not synchronized. If multiple threads will access it
concurrently, use the PriorityBlockingQueue.
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| Constructor Summary | |
| public | PriorityQueue()
Constructs a priority queue with the capacity of 11 and natural ordering. | | public | PriorityQueue(int initialCapacity)
Constructs a priority queue with specified capacity and natural ordering. | | public | PriorityQueue(int initialCapacity, Comparator<? super E> comparator)
Constructs a priority queue with specified capacity and comparator.
Parameters:
initialCapacity - the specified capacity.
Parameters:
comparator - the specified comparator. | | public | PriorityQueue(Collection<? extends E> c)
Constructs a priority queue that contains the elements of a collection.
The constructed priority queue has the initial capacity of 110% the
collection. | | public | PriorityQueue(PriorityQueue<? extends E> c)
Constructs a priority queue that contains the elements of another
priority queue. | | public | PriorityQueue(SortedSet<? extends E> c)
Constructs a priority queue that contains the elements of a sorted set.
The constructed priority queue has the initial capacity of 110% the
sorted set. |
| Method Summary | |
| public boolean | add(E o)
Adds the specified object to the priority queue.
Parameters:
o - the object to be added. | | public void | clear()
Removes all the elements of the priority queue. | | public Comparator<? super E> | comparator()
Gets the comparator of the priority queue.
the comparator of the priority queue. | | public Iterator<E> | iterator()
Gets the iterator of the priority queue, which will not return elements
in any specified ordering. | | public boolean | offer(E o)
Inserts the element to the priority queue. | | public E | peek()
Gets but not removes the head of the queue.
the head of the queue. | | public E | poll()
Gets and removes the head of the queue.
the head of the queue. | | public boolean | remove(Object o)
Removes the specified object of the priority queue.
Parameters:
o - the object to be removed. | | public int | size()
Gets the size of the priority queue. |
| PriorityQueue | | public PriorityQueue()(Code) | | Constructs a priority queue with the capacity of 11 and natural ordering.
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| PriorityQueue | | public PriorityQueue(int initialCapacity)(Code) | | Constructs a priority queue with specified capacity and natural ordering.
Parameters:
initialCapacity - the specified capacity.
throws:
IllegalArgumentException - if the initialCapacity is less than 1 |
| PriorityQueue | | public PriorityQueue(int initialCapacity, Comparator<? super E> comparator)(Code) | | Constructs a priority queue with specified capacity and comparator.
Parameters:
initialCapacity - the specified capacity.
Parameters:
comparator - the specified comparator. If it is null, the naturalordering will be used.
throws:
IllegalArgumentException - if the initialCapacity is less than 1 |
| PriorityQueue | | public PriorityQueue(Collection<? extends E> c)(Code) | | Constructs a priority queue that contains the elements of a collection.
The constructed priority queue has the initial capacity of 110% the
collection. And the priority queue uses natural ordering to order its
elements.
Parameters:
c - the collection whose elements will be added to the priorityqueue to be constructed.
throws:
ClassCastException - if any of the elements in the collection isnot comparable.
throws:
NullPointerExcepiton - if any of the elements in the collection isnull. |
| PriorityQueue | | public PriorityQueue(PriorityQueue<? extends E> c)(Code) | | Constructs a priority queue that contains the elements of another
priority queue. The constructed priority queue has the initial capacity
of 110% the latter one. And the two priority queue has the same
comparator.
Parameters:
c - the priority queue whose elements will be added to the priorityqueue to be constructed. |
| PriorityQueue | | public PriorityQueue(SortedSet<? extends E> c)(Code) | | Constructs a priority queue that contains the elements of a sorted set.
The constructed priority queue has the initial capacity of 110% the
sorted set. And the priority queue has the same comparator of the sorted
set.
Parameters:
c - the sorted set whose elements will be added to the priorityqueue to be constructed. |
| add | | public boolean add(E o)(Code) | | Adds the specified object to the priority queue.
Parameters:
o - the object to be added. true.
throws:
ClassCastException - if the element cannot be compared with theelements in the priority queue using the ordering of the priorityqueue.
throws:
NullPointerExcepiton - if the element is null. |
| clear | | public void clear()(Code) | | Removes all the elements of the priority queue.
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| comparator | | public Comparator<? super E> comparator()(Code) | | Gets the comparator of the priority queue.
the comparator of the priority queue. Null if the naturalordering is used. |
| iterator | | public Iterator<E> iterator()(Code) | | Gets the iterator of the priority queue, which will not return elements
in any specified ordering.
the iterator of the priority queue. |
| offer | | public boolean offer(E o)(Code) | | Inserts the element to the priority queue.
true
throws:
ClassCastException - if the element cannot be compared with theelements in the priority queue using the ordering of the priorityqueue.
throws:
NullPointerExcepiton - if the element is null. |
| peek | | public E peek()(Code) | | Gets but not removes the head of the queue.
the head of the queue. Null if the queue is empty. |
| poll | | public E poll()(Code) | | Gets and removes the head of the queue.
the head of the queue. Null if the queue is empty. |
| remove | | public boolean remove(Object o)(Code) | | Removes the specified object of the priority queue.
Parameters:
o - the object to be removed. true if the object is in the priority queue, false if the objectis not in the priority queue. |
| size | | public int size()(Code) | | Gets the size of the priority queue. If the size of the queue is greater
than the Integer.MAX, then it returns Integer.MAX.
the size of the priority queue. |
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