Package org.apache.zookeeper.util

Class CircularBlockingQueue<E>

  • All Implemented Interfaces:
    java.lang.Iterable<E>, java.util.Collection<E>, java.util.concurrent.BlockingQueue<E>, java.util.Queue<E>
    public class CircularBlockingQueue<E>
extends java.lang.Object
implements java.util.concurrent.BlockingQueue<E>
    A bounded 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. If the queue is full, the head of the queue (the oldest element) will be removed to make room for the newest element.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean add​(E e)  
      boolean addAll​(java.util.Collection<? extends E> arg0)  
      void clear()  
      boolean contains​(java.lang.Object o)  
      boolean containsAll​(java.util.Collection<?> arg0)  
      int drainTo​(java.util.Collection<? super E> c)  
      int drainTo​(java.util.Collection<? super E> c, int maxElements)  
      E element()  
      long getDroppedCount()
      Returns the number of elements that were dropped from the queue because the queue was full when a new element was offered.
      boolean isEmpty()  
      java.util.Iterator<E> iterator()  
      boolean offer​(E e)
      This method differs from BlockingQueue.offer(Object) in that it will remove the oldest queued element (the element at the front of the queue) in order to make room for any new elements if the queue is full.
      boolean offer​(E e, long timeout, java.util.concurrent.TimeUnit unit)  
      E peek()  
      E poll()  
      E poll​(long timeout, java.util.concurrent.TimeUnit unit)  
      void put​(E e)  
      int remainingCapacity()  
      E remove()  
      boolean remove​(java.lang.Object o)  
      boolean removeAll​(java.util.Collection<?> arg0)  
      boolean retainAll​(java.util.Collection<?> arg0)  
      int size()  
      E take()  
      java.lang.Object[] toArray()  
      <T> T[] toArray​(T[] arg0)  

      • 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, toArray

      • Methods inherited from interface java.lang.Iterable

        forEach

    • Constructor Detail

      • CircularBlockingQueue

        public CircularBlockingQueue​(int queueSize)

    • Method Detail

      • offer

        public boolean offer​(E e)
        This method differs from BlockingQueue.offer(Object) in that it will remove the oldest queued element (the element at the front of the queue) in order to make room for any new elements if the queue is full.
        Specified by:
        offer in interface java.util.concurrent.BlockingQueue<E>
        Specified by:
        offer in interface java.util.Queue<E>
        Parameters:
        e - the element to add
        Returns:
        true since it will make room for any new elements if required

      • poll

        public E poll​(long timeout,
              java.util.concurrent.TimeUnit unit)
       throws java.lang.InterruptedException
        Specified by:
        poll in interface java.util.concurrent.BlockingQueue<E>
        Throws:
        java.lang.InterruptedException

      • take

        public E take()
       throws java.lang.InterruptedException
        Specified by:
        take in interface java.util.concurrent.BlockingQueue<E>
        Throws:
        java.lang.InterruptedException

      • isEmpty

        public boolean isEmpty()
        Specified by:
        isEmpty in interface java.util.Collection<E>

      • size

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

      • getDroppedCount

        public long getDroppedCount()
        Returns the number of elements that were dropped from the queue because the queue was full when a new element was offered.
        Returns:
        The number of elements dropped (lost) from the queue

      • drainTo

        public int drainTo​(java.util.Collection<? super E> c)
        Specified by:
        drainTo in interface java.util.concurrent.BlockingQueue<E>

      • poll

        public E poll()
        Specified by:
        poll in interface java.util.Queue<E>

      • element

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

      • peek

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

      • remove

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

      • addAll

        public boolean addAll​(java.util.Collection<? extends E> arg0)
        Specified by:
        addAll in interface java.util.Collection<E>

      • clear

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

      • containsAll

        public boolean containsAll​(java.util.Collection<?> arg0)
        Specified by:
        containsAll in interface java.util.Collection<E>

      • iterator

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

      • removeAll

        public boolean removeAll​(java.util.Collection<?> arg0)
        Specified by:
        removeAll in interface java.util.Collection<E>

      • retainAll

        public boolean retainAll​(java.util.Collection<?> arg0)
        Specified by:
        retainAll in interface java.util.Collection<E>

      • toArray

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

      • toArray

        public <T> T[] toArray​(T[] arg0)
        Specified by:
        toArray in interface java.util.Collection<E>

      • add

        public boolean add​(E e)
        Specified by:
        add in interface java.util.concurrent.BlockingQueue<E>
        Specified by:
        add in interface java.util.Collection<E>
        Specified by:
        add in interface java.util.Queue<E>

      • contains

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

      • drainTo

        public int drainTo​(java.util.Collection<? super E> c,
                   int maxElements)
        Specified by:
        drainTo in interface java.util.concurrent.BlockingQueue<E>

      • offer

        public boolean offer​(E e,
                     long timeout,
                     java.util.concurrent.TimeUnit unit)
              throws java.lang.InterruptedException
        Specified by:
        offer in interface java.util.concurrent.BlockingQueue<E>
        Throws:
        java.lang.InterruptedException

      • put

        public void put​(E e)
         throws java.lang.InterruptedException
        Specified by:
        put in interface java.util.concurrent.BlockingQueue<E>
        Throws:
        java.lang.InterruptedException

      • remainingCapacity

        public int remainingCapacity()
        Specified by:
        remainingCapacity in interface java.util.concurrent.BlockingQueue<E>

      • remove

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