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java.lang.Objectjava.util.AbstractCollection<E>
java.util.AbstractQueue<E>
org.jboss.util.concurrent.DelayQueue<E>
E
- the type of elements held in this collectionpublic class DelayQueue<E extends java.util.concurrent.Delayed>
An unbounded blocking queue of Delayed elements, in which an element can only be taken when its delay has expired. The head of the queue is that Delayed element whose delay expired furthest in the past. If no delay has expired there is no head and poll will return null. Expiration occurs when an element's getDelay(TimeUnit.NANOSECONDS) method returns a value less than or equal to zero. Even though unexpired elements cannot be removed using take or poll, they are otherwise treated as normal elements. For example, the size method returns the count of both expired and unexpired elements. This queue does not permit null elements.
This class and its iterator implement all of the
optional methods of the Collection
and Iterator
interfaces.
This class is a member of the Java Collections Framework.
Constructor Summary | |
---|---|
DelayQueue()
Creates a new DelayQueue that is initially empty. |
|
DelayQueue(java.util.Collection<? extends E> c)
Creates a DelayQueue initially containing the elements of the given collection of Delayed instances. |
Method Summary | ||
---|---|---|
boolean |
add(E e)
Inserts the specified element into this delay queue. |
|
void |
clear()
Atomically removes all of the elements from this delay queue. |
|
int |
drainTo(java.util.Collection<? super E> c)
|
|
int |
drainTo(java.util.Collection<? super E> c,
int maxElements)
|
|
java.util.Iterator<E> |
iterator()
Returns an iterator over all the elements (both expired and unexpired) in this queue. |
|
boolean |
offer(E e)
Inserts the specified element into this delay queue. |
|
boolean |
offer(E e,
long timeout,
java.util.concurrent.TimeUnit unit)
Inserts the specified element into this delay queue. |
|
E |
peek()
Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty. |
|
E |
poll()
Retrieves and removes the head of this queue, or returns null if this queue has no elements with an expired delay. |
|
E |
poll(long timeout,
java.util.concurrent.TimeUnit unit)
Retrieves and removes the head of this queue, waiting if necessary until an element with an expired delay is available on this queue, or the specified wait time expires. |
|
void |
put(E e)
Inserts the specified element into this delay queue. |
|
int |
remainingCapacity()
Always returns Integer.MAX_VALUE because a DelayQueue is not capacity constrained. |
|
boolean |
remove(java.lang.Object o)
Removes a single instance of the specified element from this queue, if it is present, whether or not it has expired. |
|
int |
size()
|
|
E |
take()
Retrieves and removes the head of this queue, waiting if necessary until an element with an expired delay is available on this queue. |
|
java.lang.Object[] |
toArray()
Returns an array containing all of the elements in this queue. |
|
|
toArray(T[] a)
Returns an array containing all of the elements in this queue; the runtime type of the returned array is that of the specified array. |
Methods inherited from class java.util.AbstractQueue |
---|
addAll, element, remove |
Methods inherited from class java.util.AbstractCollection |
---|
contains, containsAll, isEmpty, removeAll, retainAll, toString |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface java.util.Queue |
---|
element, remove |
Methods inherited from interface java.util.Collection |
---|
addAll, contains, containsAll, equals, hashCode, isEmpty, removeAll, retainAll |
Constructor Detail |
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public DelayQueue()
public DelayQueue(java.util.Collection<? extends E> c)
Delayed
instances.
c
- the collection of elements to initially contain
java.lang.NullPointerException
- if the specified collection or any
of its elements are nullMethod Detail |
---|
public boolean add(E e)
add
in interface java.util.Collection<E extends java.util.concurrent.Delayed>
add
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
add
in class java.util.AbstractQueue<E extends java.util.concurrent.Delayed>
e
- the element to add
Collection.add(E)
)
java.lang.NullPointerException
- if the specified element is nullpublic boolean offer(E e)
offer
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
offer
in interface java.util.Queue<E extends java.util.concurrent.Delayed>
e
- the element to add
java.lang.NullPointerException
- if the specified element is nullpublic void put(E e)
put
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
e
- the element to add
java.lang.NullPointerException
public boolean offer(E e, long timeout, java.util.concurrent.TimeUnit unit)
offer
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
e
- the element to addtimeout
- This parameter is ignored as the method never blocksunit
- This parameter is ignored as the method never blocks
java.lang.NullPointerException
public E poll()
poll
in interface java.util.Queue<E extends java.util.concurrent.Delayed>
public E take() throws java.lang.InterruptedException
take
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
java.lang.InterruptedException
public E poll(long timeout, java.util.concurrent.TimeUnit unit) throws java.lang.InterruptedException
poll
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
java.lang.InterruptedException
public E peek()
peek
in interface java.util.Queue<E extends java.util.concurrent.Delayed>
public int size()
size
in interface java.util.Collection<E extends java.util.concurrent.Delayed>
size
in class java.util.AbstractCollection<E extends java.util.concurrent.Delayed>
public int drainTo(java.util.Collection<? super E> c)
drainTo
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
java.lang.UnsupportedOperationException
java.lang.ClassCastException
java.lang.NullPointerException
java.lang.IllegalArgumentException
public int drainTo(java.util.Collection<? super E> c, int maxElements)
drainTo
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
java.lang.UnsupportedOperationException
java.lang.ClassCastException
java.lang.NullPointerException
java.lang.IllegalArgumentException
public void clear()
clear
in interface java.util.Collection<E extends java.util.concurrent.Delayed>
clear
in class java.util.AbstractQueue<E extends java.util.concurrent.Delayed>
public int remainingCapacity()
remainingCapacity
in interface java.util.concurrent.BlockingQueue<E extends java.util.concurrent.Delayed>
public java.lang.Object[] toArray()
The returned array will be "safe" in that no references to it are maintained by this queue. (In other words, this method must allocate a new array). The caller is thus free to modify the returned array.
This method acts as bridge between array-based and collection-based APIs.
toArray
in interface java.util.Collection<E extends java.util.concurrent.Delayed>
toArray
in class java.util.AbstractCollection<E extends java.util.concurrent.Delayed>
public <T> T[] toArray(T[] a)
If this queue fits in the specified array with room to spare (i.e., the array has more elements than this queue), the element in the array immediately following the end of the queue is set to null.
Like the toArray()
method, this method acts as bridge between
array-based and collection-based APIs. Further, this method allows
precise control over the runtime type of the output array, and may,
under certain circumstances, be used to save allocation costs.
The following code can be used to dump a delay queue into a newly allocated array of Delayed:
Delayed[] a = q.toArray(new Delayed[0]);Note that toArray(new Object[0]) is identical in function to toArray().
toArray
in interface java.util.Collection<E extends java.util.concurrent.Delayed>
toArray
in class java.util.AbstractCollection<E extends java.util.concurrent.Delayed>
a
- the array into which the elements of the queue are to
be stored, if it is big enough; otherwise, a new array of the
same runtime type is allocated for this purpose
java.lang.ArrayStoreException
- if the runtime type of the specified array
is not a supertype of the runtime type of every element in
this queue
java.lang.NullPointerException
- if the specified array is nullpublic boolean remove(java.lang.Object o)
remove
in interface java.util.Collection<E extends java.util.concurrent.Delayed>
remove
in class java.util.AbstractCollection<E extends java.util.concurrent.Delayed>
public java.util.Iterator<E> iterator()
ConcurrentModificationException
, and
guarantees to traverse elements as they existed upon
construction of the iterator, and may (but is not guaranteed
to) reflect any modifications subsequent to construction.
iterator
in interface java.lang.Iterable<E extends java.util.concurrent.Delayed>
iterator
in interface java.util.Collection<E extends java.util.concurrent.Delayed>
iterator
in class java.util.AbstractCollection<E extends java.util.concurrent.Delayed>
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