Added in API level 1

DelayQueue

open class DelayQueue<E : Delayed!> : AbstractQueue<E>, BlockingQueue<E>
kotlin.Any
   ↳ java.util.AbstractCollection<E>
   ↳ java.util.AbstractQueue<E>
   ↳ java.util.concurrent.DelayQueue

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. The Iterator provided in method #iterator() is not guaranteed to traverse the elements of the DelayQueue in any particular order.

This class is a member of the Java Collections Framework.

Summary

Public constructors

Creates a new DelayQueue that is initially empty.

Creates a DelayQueue initially containing the elements of the given collection of Delayed instances.

Public methods
open Boolean
add(element: E)

Inserts the specified element into this delay queue.

open Unit

Atomically removes all of the elements from this delay queue.

open Int

open Int
drainTo(c: MutableCollection<in E>!, maxElements: Int)

open MutableIterator<E>

Returns an iterator over all the elements (both expired and unexpired) in this queue.

open Boolean
offer(e: E)

Inserts the specified element into this delay queue.

open Boolean
offer(e: E, timeout: Long, unit: TimeUnit!)

Inserts the specified element into this delay queue.

open E?

Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty.

open E?

Retrieves and removes the head of this queue, or returns null if this queue has no elements with an expired delay.

open E
poll(timeout: Long, unit: TimeUnit!)

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.

open Unit
put(e: E)

Inserts the specified element into this delay queue.

open Int

Always returns Integer.MAX_VALUE because a DelayQueue is not capacity constrained.

open Boolean
remove(element: E?)

Removes a single instance of the specified element from this queue, if it is present, whether or not it has expired.

open E

Retrieves and removes the head of this queue, waiting if necessary until an element with an expired delay is available on this queue.

open Array<Any!>

Returns an array containing all of the elements in this queue.

open Array<T>
toArray(a: Array<T>)

Returns an array containing all of the elements in this queue; the runtime type of the returned array is that of the specified array.

Inherited functions
Properties
open Int

Inherited properties

Public constructors

DelayQueue

Added in API level 1
DelayQueue()

Creates a new DelayQueue that is initially empty.

DelayQueue

Added in API level 1
DelayQueue(c: MutableCollection<out E>!)

Creates a DelayQueue initially containing the elements of the given collection of Delayed instances.

Parameters
c MutableCollection<out E>!: the collection of elements to initially contain
Exceptions
java.lang.NullPointerException if the specified collection or any of its elements are null

Public methods

add

Added in API level 1
open fun add(element: E): Boolean

Inserts the specified element into this delay queue.

Parameters
e the element to add
Return
Boolean true (as specified by Collection#add)
Exceptions
java.lang.UnsupportedOperationException if the add operation is not supported by this collection
java.lang.ClassCastException if the class of the specified element prevents it from being added to this queue
java.lang.NullPointerException if the specified element is null
java.lang.IllegalArgumentException if some property of the specified element prevents it from being added to this queue
java.lang.IllegalStateException if the element cannot be added at this time due to capacity restrictions

clear

Added in API level 1
open fun clear(): Unit

Atomically removes all of the elements from this delay queue. The queue will be empty after this call returns. Elements with an unexpired delay are not waited for; they are simply discarded from the queue.

Exceptions
java.lang.UnsupportedOperationException if the clear operation is not supported by this collection

drainTo

Added in API level 1
open fun drainTo(c: MutableCollection<in E>!): Int
Parameters
c MutableCollection<in E>!: the collection to transfer elements into
Return
Int the number of elements transferred
Exceptions
java.lang.UnsupportedOperationException if addition of elements is not supported by the specified collection
java.lang.ClassCastException if the class of an element of this queue prevents it from being added to the specified collection
java.lang.NullPointerException if the specified collection is null
java.lang.IllegalArgumentException if the specified collection is this queue, or some property of an element of this queue prevents it from being added to the specified collection

drainTo

Added in API level 1
open fun drainTo(
    c: MutableCollection<in E>!,
    maxElements: Int
): Int
Parameters
c MutableCollection<in E>!: the collection to transfer elements into
maxElements Int: the maximum number of elements to transfer
Return
Int the number of elements transferred
Exceptions
java.lang.UnsupportedOperationException if addition of elements is not supported by the specified collection
java.lang.ClassCastException if the class of an element of this queue prevents it from being added to the specified collection
java.lang.NullPointerException if the specified collection is null
java.lang.IllegalArgumentException if the specified collection is this queue, or some property of an element of this queue prevents it from being added to the specified collection

iterator

Added in API level 1
open fun iterator(): MutableIterator<E>

Returns an iterator over all the elements (both expired and unexpired) in this queue. The iterator does not return the elements in any particular order.

The returned iterator is weakly consistent.

Return
MutableIterator<E> an iterator over the elements in this queue

offer

Added in API level 1
open fun offer(e: E): Boolean

Inserts the specified element into this delay queue.

Parameters
e E: the element to add
Return
Boolean true
Exceptions
java.lang.ClassCastException if the class of the specified element prevents it from being added to this queue
java.lang.NullPointerException if the specified element is null
java.lang.IllegalArgumentException if some property of the specified element prevents it from being added to this queue

offer

Added in API level 1
open fun offer(
    e: E,
    timeout: Long,
    unit: TimeUnit!
): Boolean

Inserts the specified element into this delay queue. As the queue is unbounded this method will never block.

Parameters
e E: the element to add
timeout Long: This parameter is ignored as the method never blocks
unit TimeUnit!: This parameter is ignored as the method never blocks
Return
Boolean true
Exceptions
java.lang.InterruptedException if interrupted while waiting
java.lang.ClassCastException if the class of the specified element prevents it from being added to this queue
java.lang.NullPointerException if the specified element is null
java.lang.IllegalArgumentException if some property of the specified element prevents it from being added to this queue

peek

Added in API level 1
open fun peek(): E?

Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty. Unlike poll, if no expired elements are available in the queue, this method returns the element that will expire next, if one exists.

Return
E? the head of this queue, or null if this queue is empty

poll

Added in API level 1
open fun poll(): E?

Retrieves and removes the head of this queue, or returns null if this queue has no elements with an expired delay.

Return
E? the head of this queue, or null if this queue has no elements with an expired delay

poll

Added in API level 1
open fun poll(
    timeout: Long,
    unit: TimeUnit!
): E

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.

Parameters
timeout Long: how long to wait before giving up, in units of unit
unit TimeUnit!: a TimeUnit determining how to interpret the timeout parameter
Return
E the head of this queue, or null if the specified waiting time elapses before an element with an expired delay becomes available
Exceptions
java.lang.InterruptedException if interrupted while waiting

put

Added in API level 1
open fun put(e: E): Unit

Inserts the specified element into this delay queue. As the queue is unbounded this method will never block.

Parameters
e E: the element to add
Exceptions
java.lang.InterruptedException if interrupted while waiting
java.lang.ClassCastException if the class of the specified element prevents it from being added to this queue
java.lang.NullPointerException if the specified element is null
java.lang.IllegalArgumentException if some property of the specified element prevents it from being added to this queue

remainingCapacity

Added in API level 1
open fun remainingCapacity(): Int

Always returns Integer.MAX_VALUE because a DelayQueue is not capacity constrained.

Return
Int Integer.MAX_VALUE

remove

Added in API level 1
open fun remove(element: E?): Boolean

Removes a single instance of the specified element from this queue, if it is present, whether or not it has expired.

Parameters
o element to be removed from this queue, if present
Return
Boolean true if this queue changed as a result of the call
Exceptions
java.lang.ClassCastException if the class of the specified element is incompatible with this queue (optional)
java.lang.NullPointerException if the specified element is null (optional)
java.lang.UnsupportedOperationException if the remove operation is not supported by this collection

take

Added in API level 1
open fun take(): E

Retrieves and removes the head of this queue, waiting if necessary until an element with an expired delay is available on this queue.

Return
E the head of this queue
Exceptions
java.lang.InterruptedException if interrupted while waiting

toArray

Added in API level 1
open fun toArray(): Array<Any!>

Returns an array containing all of the elements in this queue. The returned array elements are in no particular order.

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.

Return
Array<Any!> an array containing all of the elements in this queue

toArray

Added in API level 1
open fun <T : Any!> toArray(a: Array<T>): Array<T>

Returns an array containing all of the elements in this queue; the runtime type of the returned array is that of the specified array. The returned array elements are in no particular order. If the queue fits in the specified array, it is returned therein. Otherwise, a new array is allocated with the runtime type of the specified array and the size of this queue.

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:

<code>Delayed[] a = q.toArray(new Delayed[0]);</code>
Note that toArray(new Object[0]) is identical in function to toArray().
Parameters
<T> the component type of the array to contain the collection
a Array<T>: 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
Return
Array<T> an array containing all of the elements in this queue
Exceptions
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 null

Properties

size

Added in API level 1
open val size: Int
Return
Int the number of elements in this collection