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

A bounded java.util.concurrent.blocking queue backed by an array. This queue orders elements FIFO (first-in-first-out). The head of the queue is that element that has been on the queue the longest time. The tail of the queue is that element that has been on the queue the shortest time. New elements are inserted at the tail of the queue, and the queue retrieval operations obtain elements at the head of the queue.

This is a classic "bounded buffer", in which a fixed-sized array holds elements inserted by producers and extracted by consumers. Once created, the capacity cannot be changed. Attempts to put an element into a full queue will result in the operation blocking; attempts to take an element from an empty queue will similarly block.

This class supports an optional fairness policy for ordering waiting producer and consumer threads. By default, this ordering is not guaranteed. However, a queue constructed with fairness set to true grants threads access in FIFO order. Fairness generally decreases throughput but reduces variability and avoids starvation.

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.

->array-blocking-queue clj

(->array-blocking-queue capacity)

(->array-blocking-queue capacity fair)

(->array-blocking-queue capacity fair c)

Constructor.

Creates an ArrayBlockingQueue with the given (fixed) capacity, the specified access policy and initially containing the elements of the given collection, added in traversal order of the collection's iterator.

capacity - the capacity of this queue - int fair - if true then queue accesses for threads blocked on insertion or removal, are processed in FIFO order; if false the access order is unspecified. - boolean c - the collection of elements to initially contain - java.util.Collection

throws: java.lang.IllegalArgumentException - if capacity is less than c.size(), or less than 1.

add clj

(add this e)

Inserts the specified element at the tail of this queue if it is possible to do so immediately without exceeding the queue's capacity, returning true upon success and throwing an IllegalStateException if this queue is full.

e - the element to add - E

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

throws: java.lang.IllegalStateException - if this queue is full

clear clj

(clear this)

Atomically removes all of the elements from this queue. The queue will be empty after this call returns.

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.UnsupportedOperationException - if addition of elements is not supported by the specified collection

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, waiting up to the specified wait time for space to become available if the queue is full.

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 if successful, or false if the specified waiting time elapses before space is available - boolean

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

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, waiting for space to become available if the queue is full.

e - the element to add - E

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

remaining-capacity clj

(remaining-capacity this)

Returns the number of additional elements that this queue can ideally (in the absence of memory or resource constraints) accept without blocking. This is always equal to the initial capacity of this queue less the current size of this queue.

Note that you cannot always tell if an attempt to insert an element will succeed by inspecting remainingCapacity because it may be the case that another thread is about to insert or remove an element.

returns: the remaining capacity - 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).

Removal of interior elements in circular array based queues is an intrinsically slow and disruptive operation, so should be undertaken only in exceptional circumstances, ideally only when the queue is known not to be accessible by other threads.

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.

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

to-array clj

(to-array this)

(to-array this a)

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

Suppose x is a queue known to contain only strings. The following code can be used to dump the queue into a newly allocated array of String:

String[] y = x.toArray(new String[0]);

Note that toArray(new Object[0]) is identical in function to toArray().

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 - T[]

returns: an array containing all of the elements in this queue - <T> T[]

throws: 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

to-string clj

(to-string this)

Description copied from class: AbstractCollection

returns: a string representation of this collection - java.lang.String