jdk.util.concurrent.LinkedTransferQueue — clojure-interop/java.util.concurrent 1.0.5

An unbounded TransferQueue based on linked nodes. This queue orders elements FIFO (first-in-first-out) with respect to any given producer. The head of the queue is that element that has been on the queue the longest time for some producer. The tail of the queue is that element that has been on the queue the shortest time for some producer.

Beware that, unlike in most collections, the size method is NOT a constant-time operation. Because of the asynchronous nature of these queues, determining the current number of elements requires a traversal of the elements, and so may report inaccurate results if this collection is modified during traversal. Additionally, the bulk operations addAll, removeAll, retainAll, containsAll, equals, and toArray are not guaranteed to be performed atomically. For example, an iterator operating concurrently with an addAll operation might view only some of the added elements.

This class and its iterator implement all of the optional methods of the Collection and Iterator interfaces.

Memory consistency effects: As with other concurrent collections, actions in a thread prior to placing an object into a LinkedTransferQueue happen-before actions subsequent to the access or removal of that element from the LinkedTransferQueue in another thread.

This class is a member of the

Java Collections Framework.

->linked-transfer-queue clj

(->linked-transfer-queue)

(->linked-transfer-queue c)

Constructor.

Creates a LinkedTransferQueue initially containing the elements of the given collection, added in traversal order of the collection's iterator.

c - the collection of elements to initially contain - java.util.Collection

throws: java.lang.NullPointerException - if the specified collection or any of its elements are null

add clj

(add this e)

Inserts the specified element at the tail of this queue. As the queue is unbounded, this method will never throw IllegalStateException or return false.

e - the element to add - E

returns: true (as specified by Collection.add(E)) - boolean

throws: java.lang.NullPointerException - if the specified element is null

contains clj

(contains this o)

Returns true if this queue contains the specified element. More formally, returns true if and only if this queue contains at least one element e such that o.equals(e).

o - object to be checked for containment in this queue - java.lang.Object

returns: true if this queue contains the specified element - boolean

drain-to clj

(drain-to this c)

(drain-to this c max-elements)

Description copied from interface: BlockingQueue

c - the collection to transfer elements into - java.util.Collection max-elements - the maximum number of elements to transfer - int

returns: the number of elements transferred - int

throws: java.lang.NullPointerException - if the specified collection is null

empty? clj

(empty? this)

Returns true if this queue contains no elements.

returns: true if this queue contains no elements - boolean

get-waiting-consumer-count clj

(get-waiting-consumer-count this)

Description copied from interface: TransferQueue

returns: the number of consumers waiting to receive elements - int

has-waiting-consumer? clj

(has-waiting-consumer? this)

Description copied from interface: TransferQueue

returns: true if there is at least one waiting consumer - boolean

iterator clj

(iterator this)

Returns an iterator over the elements in this queue in proper sequence. The elements will be returned in order from first (head) to last (tail).

The returned iterator is weakly consistent.

returns: an iterator over the elements in this queue in proper sequence - java.util.Iterator<E>

offer clj

(offer this e)

(offer this e timeout unit)

Inserts the specified element at the tail of this queue. As the queue is unbounded, this method will never block or return false.

e - the element to add - E timeout - how long to wait before giving up, in units of unit - long unit - a TimeUnit determining how to interpret the timeout parameter - java.util.concurrent.TimeUnit

returns: true (as specified by BlockingQueue.offer) - boolean

throws: java.lang.NullPointerException - if the specified element is null

peek clj

(peek this)

Description copied from interface: Queue

returns: the head of this queue, or null if this queue is empty - E

poll clj

(poll this)

(poll this timeout unit)

Description copied from interface: BlockingQueue

timeout - how long to wait before giving up, in units of unit - long unit - a TimeUnit determining how to interpret the timeout parameter - java.util.concurrent.TimeUnit

returns: the head of this queue, or null if the specified waiting time elapses before an element is available - E

throws: java.lang.InterruptedException - if interrupted while waiting

put clj

(put this e)

Inserts the specified element at the tail of this queue. As the queue is unbounded, this method will never block.

e - the element to add - E

throws: java.lang.NullPointerException - if the specified element is null

remaining-capacity clj

(remaining-capacity this)

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

returns: Integer.MAX_VALUE (as specified by BlockingQueue.remainingCapacity) - int

remove clj

(remove this o)

Removes a single instance of the specified element from this queue, if it is present. More formally, removes an element e such that o.equals(e), if this queue contains one or more such elements. Returns true if this queue contained the specified element (or equivalently, if this queue changed as a result of the call).

o - element to be removed from this queue, if present - java.lang.Object

returns: true if this queue changed as a result of the call - boolean

size clj

(size this)

Returns the number of elements in this queue. If this queue contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Beware that, unlike in most collections, this method is NOT a constant-time operation. Because of the asynchronous nature of these queues, determining the current number of elements requires an O(n) traversal.

returns: the number of elements in this queue - int

spliterator clj

(spliterator this)

Returns a Spliterator over the elements in this queue.

The returned spliterator is weakly consistent.

The Spliterator reports Spliterator.CONCURRENT, Spliterator.ORDERED, and Spliterator.NONNULL.

returns: a Spliterator over the elements in this queue - java.util.Spliterator<E>

take clj

(take this)

Description copied from interface: BlockingQueue

returns: the head of this queue - E

throws: java.lang.InterruptedException - if interrupted while waiting

transfer clj

(transfer this e)

Transfers the element to a consumer, waiting if necessary to do so.

More precisely, transfers the specified element immediately if there exists a consumer already waiting to receive it (in take() or timed poll), else inserts the specified element at the tail of this queue and waits until the element is received by a consumer.

e - the element to transfer - E

throws: java.lang.NullPointerException - if the specified element is null

try-transfer clj

(try-transfer this e)

(try-transfer this e timeout unit)

Transfers the element to a consumer if it is possible to do so before the timeout elapses.

More precisely, transfers the specified element immediately if there exists a consumer already waiting to receive it (in take() or timed poll), else inserts the specified element at the tail of this queue and waits until the element is received by a consumer, returning false if the specified wait time elapses before the element can be transferred.

e - the element to transfer - E timeout - how long to wait before giving up, in units of unit - long unit - a TimeUnit determining how to interpret the timeout parameter - java.util.concurrent.TimeUnit

returns: true if successful, or false if the specified waiting time elapses before completion, in which case the element is not left enqueued - boolean

throws: java.lang.NullPointerException - if the specified element is null