Package org.apache.commons.collections.buffer

Class BoundedFifoBuffer

  • All Implemented Interfaces:
    Serializable, Iterable, Collection, BoundedCollection, Buffer
    Direct Known Subclasses:
    CircularFifoBuffer
    public class BoundedFifoBuffer
extends AbstractCollection
implements Buffer, BoundedCollection, Serializable
    The BoundedFifoBuffer is a very efficient implementation of Buffer that is of a fixed size.

    The removal order of a BoundedFifoBuffer is based on the insertion order; elements are removed in the same order in which they were added. The iteration order is the same as the removal order.

    The add(Object), remove() and get() operations all perform in constant time. All other operations perform in linear time or worse.

    Note that this implementation is not synchronized. The following can be used to provide synchronized access to your BoundedFifoBuffer: 

       Buffer fifo = BufferUtils.synchronizedBuffer(new BoundedFifoBuffer());

    This buffer prevents null objects from being added.

    This class is Serializable from Commons Collections 3.1.

    Since:
    Commons Collections 3.0 (previously in main package v2.1)
    Version:
    $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
    Author:
    Avalon, Berin Loritsch, Paul Jack, Stephen Colebourne, Herve Quiroz
    See Also:
    Serialized Form

    • Constructor Detail

      • BoundedFifoBuffer

        public BoundedFifoBuffer()
        Constructs a new BoundedFifoBuffer big enough to hold 32 elements.

      • BoundedFifoBuffer

        public BoundedFifoBuffer​(int size)
        Constructs a new BoundedFifoBuffer big enough to hold the specified number of elements.
        Parameters:
        size - the maximum number of elements for this fifo
        Throws:
        IllegalArgumentException - if the size is less than 1

      • BoundedFifoBuffer

        public BoundedFifoBuffer​(Collection coll)
        Constructs a new BoundedFifoBuffer big enough to hold all of the elements in the specified collection. That collection's elements will also be added to the buffer.
        Parameters:
        coll - the collection whose elements to add, may not be null
        Throws:
        NullPointerException - if the collection is null

    • Method Detail

      • size

        public int size()
        Returns the number of elements stored in the buffer.
        Specified by:
        size in interface Collection
        Specified by:
        size in class AbstractCollection
        Returns:
        this buffer's size

      • isEmpty

        public boolean isEmpty()
        Returns true if this buffer is empty; false otherwise.
        Specified by:
        isEmpty in interface Collection
        Overrides:
        isEmpty in class AbstractCollection
        Returns:
        true if this buffer is empty

      • isFull

        public boolean isFull()
        Returns true if this collection is full and no new elements can be added.
        Specified by:
        isFull in interface BoundedCollection
        Returns:
        true if the collection is full

      • maxSize

        public int maxSize()
        Gets the maximum size of the collection (the bound).
        Specified by:
        maxSize in interface BoundedCollection
        Returns:
        the maximum number of elements the collection can hold

      • get

        public Object get()
        Returns the least recently inserted element in this buffer.
        Specified by:
        get in interface Buffer
        Returns:
        the least recently inserted element
        Throws:
        BufferUnderflowException - if the buffer is empty

      • remove

        public Object remove()
        Removes the least recently inserted element from this buffer.
        Specified by:
        remove in interface Buffer
        Returns:
        the least recently inserted element
        Throws:
        BufferUnderflowException - if the buffer is empty