org.apache.commons.collections.buffer

Class CircularFifoBuffer

public class CircularFifoBuffer extends BoundedFifoBuffer

CircularFifoBuffer is a first in first out buffer with a fixed size that replaces its oldest element if full.

The removal order of a CircularFifoBuffer 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, CircularFifoBuffer and CircularFifoBuffer 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 CircularFifoBuffer:

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

This buffer prevents null objects from being added.

This class is Serializable from Commons Collections 3.1.

Since: Commons Collections 3.0

Version: $Revision: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $

Author: Stefano Fornari Stephen Colebourne

Constructor Summary
CircularFifoBuffer()
Constructor that creates a buffer with the default size of 32.
CircularFifoBuffer(int size)
Constructor that creates a buffer with the specified size.
CircularFifoBuffer(Collection coll)
Constructor that creates a buffer from the specified collection.
Method Summary
booleanadd(Object element)
If the buffer is full, the least recently added element is discarded so that a new element can be inserted.

Constructor Detail

CircularFifoBuffer

public CircularFifoBuffer()
Constructor that creates a buffer with the default size of 32.

CircularFifoBuffer

public CircularFifoBuffer(int size)
Constructor that creates a buffer with the specified size.

Parameters: size the size of the buffer (cannot be changed)

Throws: IllegalArgumentException if the size is less than 1

CircularFifoBuffer

public CircularFifoBuffer(Collection coll)
Constructor that creates a buffer from the specified collection. The collection size also sets the buffer size

Parameters: coll the collection to copy into the buffer, may not be null

Throws: NullPointerException if the collection is null

Method Detail

add

public boolean add(Object element)
If the buffer is full, the least recently added element is discarded so that a new element can be inserted.

Parameters: element the element to add

Returns: true, always

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