public class UnboundedFifoBuffer extends java.util.AbstractCollection implements Buffer, java.io.Serializable
Buffer
that can grow to any size.
According to performance testing, it exhibits a constant access time, but it
also outperforms ArrayList when used for the same purpose.
The removal order of an UnboundedFifoBuffer
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 remove()
and get()
operations perform in constant time.
The add(Object)
operation performs in amortized 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 UnboundedFifoBuffer
:
Buffer fifo = BufferUtils.synchronizedBuffer(new UnboundedFifoBuffer());
This buffer prevents null objects from being added.
This class is Serializable from Commons Collections 3.1.
Modifier and Type | Field and Description |
---|---|
protected java.lang.Object[] |
buffer
The array of objects in the buffer.
|
protected int |
head
The current head index.
|
private static long |
serialVersionUID
Serialization vesrion
|
protected int |
tail
The current tail index.
|
Constructor and Description |
---|
UnboundedFifoBuffer()
Constructs an UnboundedFifoBuffer with the default number of elements.
|
UnboundedFifoBuffer(int initialSize)
Constructs an UnboundedFifoBuffer with the specified number of elements.
|
Modifier and Type | Method and Description |
---|---|
boolean |
add(java.lang.Object obj)
Adds the given element to this buffer.
|
private int |
decrement(int index)
Decrements the internal index.
|
java.lang.Object |
get()
Returns the next object in the buffer.
|
private int |
increment(int index)
Increments the internal index.
|
boolean |
isEmpty()
Returns true if this buffer is empty; false otherwise.
|
java.util.Iterator |
iterator()
Returns an iterator over this buffer's elements.
|
private void |
readObject(java.io.ObjectInputStream in)
Read the buffer in using a custom routine.
|
java.lang.Object |
remove()
Removes the next object from the 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, clear, contains, containsAll, remove, removeAll, retainAll, toArray, toArray, toString
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
private static final long serialVersionUID
protected transient java.lang.Object[] buffer
protected transient int head
protected transient int tail
public UnboundedFifoBuffer()
new UnboundedFifoBuffer(32);
public UnboundedFifoBuffer(int initialSize)
initialSize
- the initial size of the bufferjava.lang.IllegalArgumentException
- if the size is less than 1private 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 add(java.lang.Object obj)
add
in interface java.util.Collection
add
in class java.util.AbstractCollection
obj
- the element to addjava.lang.NullPointerException
- if the given element is nullpublic java.lang.Object get()
get
in interface Buffer
BufferUnderflowException
- if this buffer is emptypublic java.lang.Object remove()
remove
in interface Buffer
BufferUnderflowException
- if this 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