public class BoundedFifoBuffer extends java.util.AbstractCollection implements Buffer, BoundedCollection, java.io.Serializable
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.
Modifier and Type | Field and Description |
---|---|
private java.lang.Object[] |
elements
Underlying storage array
|
private int |
end
Index mod maxElements of the array position following the last buffer
element.
|
private boolean |
full
Flag to indicate if the buffer is currently full.
|
private int |
maxElements
Capacity of the buffer
|
private static long |
serialVersionUID
Serialization version
|
private int |
start
Array index of first (oldest) buffer element
|
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. |
Modifier and Type | Method and Description |
---|---|
boolean |
add(java.lang.Object element)
Adds the given element to this buffer.
|
void |
clear()
Clears this buffer.
|
private int |
decrement(int index)
Decrements the internal index.
|
java.lang.Object |
get()
Returns the least recently inserted element in this buffer.
|
private int |
increment(int index)
Increments the internal index.
|
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).
|
private void |
readObject(java.io.ObjectInputStream in)
Read the buffer in using a custom routine.
|
java.lang.Object |
remove()
Removes the least recently inserted element from this buffer.
|
int |
size()
Returns the number of elements stored in the buffer.
|
private void |
writeObject(java.io.ObjectOutputStream out)
Write the buffer out using a custom routine.
|
addAll, contains, containsAll, remove, removeAll, retainAll, toArray, toArray, toString
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
private static final long serialVersionUID
private transient java.lang.Object[] elements
private transient int start
private transient int end
private transient boolean full
private final int maxElements
public BoundedFifoBuffer()
BoundedFifoBuffer
big enough to hold
32 elements.public BoundedFifoBuffer(int size)
BoundedFifoBuffer
big enough to hold
the specified number of elements.size
- the maximum number of elements for this fifojava.lang.IllegalArgumentException
- if the size is less than 1public BoundedFifoBuffer(java.util.Collection coll)
BoundedFifoBuffer
big enough to hold all
of the elements in the specified collection. That collection's
elements will also be added to the buffer.coll
- the collection whose elements to add, may not be nulljava.lang.NullPointerException
- if the collection is nullprivate void writeObject(java.io.ObjectOutputStream out) throws java.io.IOException
out
- the output streamjava.io.IOException
private void readObject(java.io.ObjectInputStream in) throws java.io.IOException, java.lang.ClassNotFoundException
in
- the input streamjava.io.IOException
java.lang.ClassNotFoundException
public int size()
size
in interface java.util.Collection
size
in class java.util.AbstractCollection
public boolean isEmpty()
isEmpty
in interface java.util.Collection
isEmpty
in class java.util.AbstractCollection
public boolean isFull()
isFull
in interface BoundedCollection
true
if the collection is fullpublic int maxSize()
maxSize
in interface BoundedCollection
public void clear()
clear
in interface java.util.Collection
clear
in class java.util.AbstractCollection
public boolean add(java.lang.Object element)
add
in interface java.util.Collection
add
in class java.util.AbstractCollection
element
- the element to addjava.lang.NullPointerException
- if the given element is nullBufferOverflowException
- if this buffer is fullpublic java.lang.Object get()
get
in interface Buffer
BufferUnderflowException
- if the buffer is emptypublic java.lang.Object remove()
remove
in interface Buffer
BufferUnderflowException
- if the buffer is emptyprivate int increment(int index)
index
- the index to incrementprivate int decrement(int index)
index
- the index to decrementpublic java.util.Iterator iterator()
iterator
in interface java.lang.Iterable
iterator
in interface java.util.Collection
iterator
in class java.util.AbstractCollection