org.onosproject.store.service

Interface DistributedQueue<E>

Type Parameters:

E - queue entry type

public interface DistributedQueue<E>

A distributed collection designed for holding elements prior to processing. A queue provides insertion, extraction and inspection operations. The extraction operation is designed to be non-blocking.

Method Summary

Modifier and Type	Method and Description
default boolean	isEmpty() Returns true if queue has elements in it.
E	peek() Returns an entry from the queue without removing it.
CompletableFuture<E>	pop() If the queue is non-empty, an entry will be removed from the queue and the returned future will be immediately completed with it.
void	push(E entry) Inserts an entry into the queue.
long	size() Returns total number of entries in the queue.

Method Detail

size

long size()

Returns total number of entries in the queue.

Returns:

queue size

isEmpty

default boolean isEmpty()

Returns true if queue has elements in it.

Returns:

true is queue has elements, false otherwise

push

void push(E entry)

Inserts an entry into the queue.

Parameters:

entry - entry to insert

pop

CompletableFuture<E> pop()

If the queue is non-empty, an entry will be removed from the queue and the returned future will be immediately completed with it. If queue is empty when this call is made, the returned future will be eventually completed when an entry is added to the queue.

Returns:

queue entry

peek

E peek()

Returns an entry from the queue without removing it. If the queue is empty returns null.

Returns:

queue entry or null if queue is empty