org.apache.commons.collections.buffer

Class BoundedFifoBuffer

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, 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: 405927 $ $Date: 2006-05-12 23:57:03 +0100 (Fri, 12 May 2006) $

Author: Avalon Berin Loritsch Paul Jack Stephen Colebourne Herve Quiroz

Constructor Summary
BoundedFifoBuffer()
Constructs a new BoundedFifoBuffer big enough to hold 32 elements.
BoundedFifoBuffer(int size)
Constructs a new BoundedFifoBuffer big enough to hold the specified number of elements.
BoundedFifoBuffer(Collection coll)
Constructs a new BoundedFifoBuffer big enough to hold all of the elements in the specified collection.
Method Summary
booleanadd(Object element)
Adds the given element to this buffer.
voidclear()
Clears this buffer.
Objectget()
Returns the least recently inserted element in this buffer.
booleanisEmpty()
Returns true if this buffer is empty; false otherwise.
booleanisFull()
Returns true if this collection is full and no new elements can be added.
Iteratoriterator()
Returns an iterator over this buffer's elements.
intmaxSize()
Gets the maximum size of the collection (the bound).
Objectremove()
Removes the least recently inserted element from this buffer.
intsize()
Returns the number of elements stored in the buffer.

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

add

public boolean add(Object element)
Adds the given element to this buffer.

Parameters: element the element to add

Returns: true, always

Throws: NullPointerException if the given element is null BufferOverflowException if this buffer is full

clear

public void clear()
Clears this buffer.

get

public Object get()
Returns the least recently inserted element in this buffer.

Returns: the least recently inserted element

Throws: BufferUnderflowException if the buffer is empty

isEmpty

public boolean isEmpty()
Returns true if this buffer is empty; false otherwise.

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.

Returns: true if the collection is full

iterator

public Iterator iterator()
Returns an iterator over this buffer's elements.

Returns: an iterator over this buffer's elements

maxSize

public int maxSize()
Gets the maximum size of the collection (the bound).

Returns: the maximum number of elements the collection can hold

remove

public Object remove()
Removes the least recently inserted element from this buffer.

Returns: the least recently inserted element

Throws: BufferUnderflowException if the buffer is empty

size

public int size()
Returns the number of elements stored in the buffer.

Returns: this buffer's size

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