Interface CircularQueue<E>



  • public interface CircularQueue<E>
    Definition of interface queue that maintains the queue size by removing elements from the head of the queue if the capacity is violated. This queue orders elements FIFO (first-in-first-out).
    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method and Description
      void addAll(java.util.Collection<? extends E> collection)
      Appends all of the elements in the specified collection to the end of this queue, in the order that they are returned by the specified collection's iterator.
      void clear()
      Removes all of the elements from this queue.
      boolean contains(E element)
      Returns true if this queue contains the specified element.
      boolean isEmpty()
      Returns true if this queue contains no elements.
      void offer(E element)
      Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions.
      E poll()
      Retrieves and removes the head of this queue, or returns null if this queue is empty.
      int size()
      Returns the number of elements in this queue.
      E[] toArray(E[] 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.
    • Method Detail

      • offer

        void offer(E element)
        Inserts the specified element into this queue if it is possible to do so immediately without violating capacity restrictions.

        Violating capacity restrictions will result in a removal of an element at the head of the queue to accommodate space in the queue for a newly added element.

        Parameters:
        element - to add
      • poll

        E poll()
        Retrieves and removes the head of this queue, or returns null if this queue is empty.
        Returns:
        the head of this queue, or null if this queue is empty
        See Also:
        Queue.poll()
      • addAll

        void addAll(java.util.Collection<? extends E> collection)
        Appends all of the elements in the specified collection to the end of this queue, in the order that they are returned by the specified collection's iterator. Attempts to addAll of a queue to itself result in IllegalArgumentException.
        Parameters:
        collection - the elements to be inserted into this queue
        See Also:
        Collection.addAll(Collection)
      • isEmpty

        boolean isEmpty()
        Returns true if this queue contains no elements.
        Returns:
        true if this queue contains no elements
        See Also:
        Collection.isEmpty()
      • size

        int size()
        Returns the number of elements in this queue.
        Returns:
        the number of elements in this queue
        See Also:
        Collection.size()
      • clear

        void clear()
        Removes all of the elements from this queue. The queue will be empty after this call returns.
        See Also:
        Collection.clear()
      • toArray

        E[] toArray(E[] 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.
        Parameters:
        a - The array into which the elements of the queue are to be stored.
        Returns:
        an array of the elements
        See Also:
        Collection.toArray(Object[])
      • contains

        boolean contains(E element)
        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==null ? e==null : o.equals(e)).
        Parameters:
        element - to look for in the queue
        Returns:
        true if this queue contains the specified element