Package io.smallrye.mutiny.helpers.queues

Class MpscLinkedQueue<T>

  • Type Parameters:
    T - the contained value type
    All Implemented Interfaces:
    java.lang.Iterable<T>, java.util.Collection<T>, java.util.Queue<T>
    public final class MpscLinkedQueue<T>
extends java.lang.Object
implements java.util.Queue<T>
    A multi-producer single consumer unbounded queue. Code from RX Java 2.

    • Constructor Summary

      Constructors 
      Constructor Description
      MpscLinkedQueue()  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean add​(T t)  
      boolean addAll​(java.util.Collection<? extends T> c)  
      void clear()  
      boolean contains​(java.lang.Object o)  
      boolean containsAll​(java.util.Collection<?> c)  
      T element()  
      boolean isEmpty()

      java.util.Iterator<T> iterator()  
      boolean offer​(T e)

      T peek()  
      T poll()

      T remove()  
      boolean remove​(java.lang.Object o)  
      boolean removeAll​(java.util.Collection<?> c)  
      boolean retainAll​(java.util.Collection<?> c)  
      int size()  
      java.lang.Object[] toArray()  
      <T1> T1[] toArray​(T1[] a)  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

      • Methods inherited from interface java.util.Collection

        equals, hashCode, parallelStream, removeIf, spliterator, stream

      • Methods inherited from interface java.lang.Iterable

        forEach

    • Constructor Detail

      • MpscLinkedQueue

        public MpscLinkedQueue()

    • Method Detail

      • add

        public boolean add​(T t)
        Specified by:
        add in interface java.util.Collection<T>
        Specified by:
        add in interface java.util.Queue<T>

      • remove

        public boolean remove​(java.lang.Object o)
        Specified by:
        remove in interface java.util.Collection<T>

      • containsAll

        public boolean containsAll​(java.util.Collection<?> c)
        Specified by:
        containsAll in interface java.util.Collection<T>

      • addAll

        public boolean addAll​(java.util.Collection<? extends T> c)
        Specified by:
        addAll in interface java.util.Collection<T>

      • removeAll

        public boolean removeAll​(java.util.Collection<?> c)
        Specified by:
        removeAll in interface java.util.Collection<T>

      • retainAll

        public boolean retainAll​(java.util.Collection<?> c)
        Specified by:
        retainAll in interface java.util.Collection<T>

      • offer

        public boolean offer​(T e)

        IMPLEMENTATION NOTES:
        Offer is allowed from multiple threads.
        Offer allocates a new node and:

        1. Swaps it atomically with current producer node (only one producer 'wins')
        2. Sets the new node as the node following from the swapped producer node
        This works because each producer is guaranteed to 'plant' a new node and link the old node. No 2 producers can get the same producer node as part of XCHG guarantee.
        Specified by:
        offer in interface java.util.Queue<T>
        See Also:
        Queue.offer(Object)

      • remove

        public T remove()
        Specified by:
        remove in interface java.util.Queue<T>

      • poll

        public T poll()

        IMPLEMENTATION NOTES:
        Poll is allowed from a SINGLE thread.
        Poll reads the next node from the consumerNode and:

        1. If it is null, the queue is assumed empty (though it might not be).
        2. If it is not null set it as the consumer node and return it's now evacuated value.
        This means the consumerNode.value is always null, which is also the starting point for the queue. Because null values are not allowed to be offered this is the only node with it's value set to null at any one time.
        Specified by:
        poll in interface java.util.Queue<T>
        See Also:
        Queue.poll()

      • element

        public T element()
        Specified by:
        element in interface java.util.Queue<T>

      • peek

        public T peek()
        Specified by:
        peek in interface java.util.Queue<T>

      • clear

        public void clear()
        Specified by:
        clear in interface java.util.Collection<T>

      • size

        public int size()
        Specified by:
        size in interface java.util.Collection<T>

      • isEmpty

        public boolean isEmpty()

        IMPLEMENTATION NOTES:
        Queue is empty when producerNode is the same as consumerNode. An alternative implementation would be to observe the producerNode.value is null, which also means an empty queue because only the consumerNode.value is allowed to be null.

        Specified by:
        isEmpty in interface java.util.Collection<T>

      • contains

        public boolean contains​(java.lang.Object o)
        Specified by:
        contains in interface java.util.Collection<T>

      • iterator

        public java.util.Iterator<T> iterator()
        Specified by:
        iterator in interface java.util.Collection<T>
        Specified by:
        iterator in interface java.lang.Iterable<T>

      • toArray

        public java.lang.Object[] toArray()
        Specified by:
        toArray in interface java.util.Collection<T>

      • toArray

        public <T1> T1[] toArray​(T1[] a)
        Specified by:
        toArray in interface java.util.Collection<T>