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org.apache.commons.collections.buffer

Class CircularFifoBuffer

AbstractCollection
|
+--org.apache.commons.collections.buffer.BoundedFifoBuffer
   |
   +--org.apache.commons.collections.buffer.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(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 CircularFifoBuffer:

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

This buffer prevents null objects from being added.

Since:
Commons Collections 3.0
Authors:
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

boolean

add(Object element)

If the buffer is full, the least recently added element is discarded so that a new element can be inserted.

Constructor Details

CircularFifoBuffer

public CircularFifoBuffer()

Constructor that creates a buffer with the default size of 32.


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:
- if the collection is null

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:
- if the size is less than 1

Method Details

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