de.caff.util

Class RingBuffer<T>

java.lang.Object

de.caff.util.RingBuffer<T>

public class RingBuffer<T>
extends java.lang.Object

A byte buffer to which you can add data up to a maximum size.

If the buffer overflows you can only retrieve the latest getLimit() bytes.

Since:

August 10, 2022

Author:

Rammi

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static int	INITIAL_LIMIT Initial limit: 1 MiB.

Constructor Summary

Constructors

Constructor and Description
RingBuffer(int limit) Create a ring buffer with the given size.
RingBuffer(int limit, int initialLimit) Create a ring buffer with the given size.

Method Summary

Modifier and Type	Method and Description
void	append(T... items) Append the given items to the buffer.
void	append(T item) Append one item.
void	append(T[] items, int offset, int length) Append the given byte array part to this buffer.
void	clear() Clear all data.
int	getLimit() Get the limit of this ring buffer.
long	getNumberOfCollectedItems() Get the total number of items appended to this buffer.
boolean	isEmpty() Is this ring buffer empty?
int	size() Get the number of valid bytes cached in this buffer.
Indexable<T>	toIndexable() Get a stable byte indexable from this buffer.
java.util.List<T>	toList() Create a list with the items in this buffer.
Indexable<T>	view() Get an indexable view of this ring buffer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INITIAL_LIMIT

static final int INITIAL_LIMIT

Initial limit: 1 MiB.

See Also:

Constant Field Values

Constructor Detail

RingBuffer

public RingBuffer(int limit)

Create a ring buffer with the given size.

Parameters:

limit - size limit of this buffer

RingBuffer

RingBuffer(int limit,
           int initialLimit)

Create a ring buffer with the given size. This allows to set the initial limit for testing.

Parameters:

limit - size limit of this buffer

initialLimit - initial limit

Method Detail

getLimit

public int getLimit()

Get the limit of this ring buffer.

Returns:

buffer limit

size

public int size()

Get the number of valid bytes cached in this buffer.

Returns:

number of bytes cached

isEmpty

public boolean isEmpty()

Is this ring buffer empty?

Returns:

true if the buffer is empty
false if not

append

public void append(T item)

Append one item.

Parameters:

item - item to append

append

@SafeVarargs
public final void append(@NotNull
                                      T... items)

Append the given items to the buffer.

Parameters:

items - items to append

append

public void append(@NotNull
                   T[] items,
                   int offset,
                   int length)

Append the given byte array part to this buffer.

Parameters:

items - items to append

offset - start offset of the bytes to append

length - number of bytes to append

Throws:

java.lang.IndexOutOfBoundsException - if the parameters define a part which is at least partially outside the bytes

toList

@NotNull
public java.util.List<T> toList()

Create a list with the items in this buffer.

Returns:

list of size size() containing the buffered items

view

@NotNull
public Indexable<T> view()

Get an indexable view of this ring buffer.

This is more efficient than copying all bytes in toList(), especially if only a few items of a larger content are of interest. But the price is high: any change to this buffer can break the returned view. So this is best used on a finished buffer.

Returns:

indexable view of this buffer

See Also:

toIndexable(), toList()

toIndexable

@NotNull
public Indexable<T> toIndexable()

Get a stable byte indexable from this buffer.

Compared to view() the returned indexable is decoupled from this buffer, with the price of a copy of the bytes. Compared to the result of

 ByteIndexable.viewArray(ringBuffer.toByteArray())
 

this method provides an already frozen byte indexable.

Returns:

stable frozen byte indexable

See Also:

toList(), view()

clear

public void clear()

Clear all data. This will clear everything but the total number of bytes handled by this buffer.

getNumberOfCollectedItems

public long getNumberOfCollectedItems()

Get the total number of items appended to this buffer.

Returns:

total number of appended items