org.apache.commons.collections.buffer

Class BoundedFifoBuffer

Implemented Interfaces:
BoundedCollection, Buffer, Collection, Serializable
Known Direct Subclasses:
CircularFifoBuffer

public class BoundedFifoBuffer
extends AbstractCollection
implements Buffer, BoundedCollection, Serializable

The BoundedFifoBuffer is a very efficient implementation of Buffer that does not alter the size of the buffer at runtime.

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.

Version:
$Revision: 1.8 $ $Date: 2004/06/02 23:12:44 $
Authors:
Avalon
Berin Loritsch
Paul Jack
Stephen Colebourne
Herve Quiroz
Since:
Commons Collections 3.0 (previously in main package v2.1)

Constructor Summary

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

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.

Constructor Details

BoundedFifoBuffer

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

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

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

Method Details

add

public boolean add(Object element)
Adds the given element to this buffer.
Parameters:
element - the element to add
Returns:
true, always

clear

public void clear()
Clears this buffer.

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

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.
Specified by:
isFull in interface BoundedCollection
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).
Specified by:
maxSize in interface BoundedCollection
Returns:
the maximum number of elements the collection can hold

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

size

public int size()
Returns the number of elements stored in the buffer.
Returns:
this buffer's size

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