org.apache.commons.collections.buffer

## Class BoundedFifoBuffer

- java.lang.Object
- - java.util.AbstractCollection
  - - org.apache.commons.collections.buffer.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 Summary

    Constructors
    Constructor and Description
    `BoundedFifoBuffer()` Constructs a new `BoundedFifoBuffer` big enough to hold 32 elements.
    `BoundedFifoBuffer(Collection coll)` Constructs a new `BoundedFifoBuffer` big enough to hold all of the elements in the specified collection.
    `BoundedFifoBuffer(int size)` Constructs a new `BoundedFifoBuffer` big enough to hold the specified number of elements.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `add(Object element)` Adds the given element to this buffer.
    `void` | `clear()` Clears this buffer.
    `Object` | `get()` Returns the least recently inserted element in this buffer.
    `boolean` | `isEmpty()` Returns true if this buffer is empty; false otherwise.
    `boolean` | `isFull()` Returns true if this collection is full and no new elements can be added.
    `Iterator` | `iterator()` Returns an iterator over this buffer's elements.
    `int` | `maxSize()` Gets the maximum size of the collection (the bound).
    `Object` | `remove()` Removes the least recently inserted element from this buffer.
    `int` | `size()` Returns the number of elements stored in the buffer.

    - ### Methods inherited from class java.util.AbstractCollection

      `addAll, contains, containsAll, remove, removeAll, retainAll, toArray, toArray, toString`

    - ### Methods inherited from class java.lang.Object

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

    - ### Methods inherited from interface java.util.Collection

      `addAll, contains, containsAll, equals, hashCode, remove, removeAll, retainAll, toArray, toArray`

- - ### 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

    - #### clear

          public void clear()

      Clears this buffer.
      Specified by:
        `clear` in interface `Collection`
      Overrides:
        `clear` in class `AbstractCollection`

    - #### add

          public boolean add(Object element)

      Adds the given element to this buffer.
      Specified by:
        `add` in interface `Collection`
      Overrides:
        `add` in class `AbstractCollection`
      Parameters:
        `element` - the element to add
      Returns:
        true, always
      Throws:
        `NullPointerException` - if the given element is null
        `BufferOverflowException` - if this buffer is full

    - #### 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

    - #### iterator

          public Iterator iterator()

      Returns an iterator over this buffer's elements.
      Specified by:
        `iterator` in interface `Iterable`
      Specified by:
        `iterator` in interface `Collection`
      Specified by:
        `iterator` in class `AbstractCollection`
      Returns:
        an iterator over this buffer's elements

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