org.apache.commons.collections.buffer

Class BoundedFifoBuffer

java.lang.Object

java.util.AbstractCollection

org.apache.commons.collections.buffer.BoundedFifoBuffer

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable, java.util.Collection, BoundedCollection, Buffer

Direct Known Subclasses:

CircularFifoBuffer

public class BoundedFifoBuffer
extends java.util.AbstractCollection
implements Buffer, BoundedCollection, java.io.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)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
BoundedFifoBuffer() Constructs a new BoundedFifoBuffer big enough to hold 32 elements.
BoundedFifoBuffer(java.util.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

Modifier and Type	Method and Description
boolean	add(java.lang.Object element) Adds the given element to this buffer.
void	clear() Clears this buffer.
java.lang.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.
java.util.Iterator	iterator() Returns an iterator over this buffer's elements.
int	maxSize() Gets the maximum size of the collection (the bound).
java.lang.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

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

addAll, contains, containsAll, equals, hashCode, parallelStream, remove, removeAll, removeIf, retainAll, spliterator, stream, toArray, toArray

Methods inherited from interface java.lang.Iterable

forEach

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:

java.lang.IllegalArgumentException - if the size is less than 1

BoundedFifoBuffer

public BoundedFifoBuffer(java.util.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:

java.lang.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 java.util.Collection

Specified by:

size in class java.util.AbstractCollection

Returns:

this buffer's size

isEmpty

public boolean isEmpty()

Returns true if this buffer is empty; false otherwise.

Specified by:

isEmpty in interface java.util.Collection

Overrides:

isEmpty in class java.util.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 java.util.Collection

Overrides:

clear in class java.util.AbstractCollection

add

public boolean add(java.lang.Object element)

Adds the given element to this buffer.

Specified by:

add in interface java.util.Collection

Overrides:

add in class java.util.AbstractCollection

Parameters:

element - the element to add

Returns:

true, always

Throws:

java.lang.NullPointerException - if the given element is null

BufferOverflowException - if this buffer is full

get

public java.lang.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 java.lang.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 java.util.Iterator iterator()

Returns an iterator over this buffer's elements.

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Specified by:

iterator in class java.util.AbstractCollection

Returns:

an iterator over this buffer's elements