com.aoindustries.util

Class BufferManager

java.lang.Object

com.aoindustries.util.BufferManager

public final class BufferManager
extends Object

BufferManager manages a reusable pool of byte[] and char[] buffers. This avoids the repetitive allocation of memory for an operation that only needs a temporary buffer. The buffers are stored as ThreadLocal to maximize cache locality.

Do not use if intra-thread security is more important than performance.

The buffers are not necessarily cleared between invocations so the results of previous operations may be available to additional callers. On the scale of security versus performance, this is biased toward performance. However, being thread local there remains some control over the visibility of the data.

Buffers must not be passed between threads, as each thread has an unlimited number of possible buffers. Giving a thread a buffer you didn't get from it could result in a memory leak.

TODO: Implement as concurrent queue/deque instead of thread locals?

Author:

AO Industries, Inc.

Field Summary

Fields

Modifier and Type	Field and Description
static int	BUFFER_SIZE The size of buffers that are returned.

Method Summary

Modifier and Type	Method and Description
static long	getByteBufferCreates()
static long	getByteBufferUses()
static byte[]	getBytes() Gets a byte[] of length BUFFER_SIZE that may be temporarily used for any purpose.
static long	getCharBufferCreates()
static long	getCharBufferUses()
static char[]	getChars() Gets a char[] of length BUFFER_SIZE that may be temporarily used for any purpose.
static void	release(byte[] buffer) Deprecated. May obtain greater performance by avoiding zero fill on non-sensitive data.
static void	release(byte[] buffer, boolean zeroFill) Releases a byte[] that was obtained by a call to getBytes.
static void	release(char[] buffer) Deprecated. May obtain greater performance by avoiding zero fill on non-sensitive data.
static void	release(char[] buffer, boolean zeroFill) Releases a char[] that was obtained by a call to getChars.

Methods inherited from class java.lang.Object

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

Field Detail

BUFFER_SIZE

public static final int BUFFER_SIZE

The size of buffers that are returned.

See Also:

Constant Field Values

Method Detail

getBytes

public static byte[] getBytes()

Gets a byte[] of length BUFFER_SIZE that may be temporarily used for any purpose. Once done with the buffer, releaseBuffer should be called, this is best accomplished in a finally block. The buffer is not necessarily zero-filled and may contain data from a previous use.

getChars

public static char[] getChars()

Gets a char[] of length BUFFER_SIZE that may be temporarily used for any purpose. Once done with the buffer, releaseBuffer should be called, this is best accomplished in a finally block. The buffer is not necessarily zero-filled and may contain data from a previous use.

release

@Deprecated
public static void release(byte[] buffer)

Deprecated. May obtain greater performance by avoiding zero fill on non-sensitive data.

release

public static void release(byte[] buffer,
                           boolean zeroFill)

Releases a byte[] that was obtained by a call to getBytes.

Parameters:

buffer - the byte[] to release

zeroFill - if the data in the buffer may be sensitive, it is best to zero-fill the buffer on release.

release

@Deprecated
public static void release(char[] buffer)

Deprecated. May obtain greater performance by avoiding zero fill on non-sensitive data.

release

public static void release(char[] buffer,
                           boolean zeroFill)

Releases a char[] that was obtained by a call to getChars.

Parameters:

buffer - the char[] to release

zeroFill - if the data in the buffer may be sensitive, it is best to zero-fill the buffer on release.

getByteBufferCreates

public static long getByteBufferCreates()

getByteBufferUses

public static long getByteBufferUses()

getCharBufferCreates

public static long getCharBufferCreates()

getCharBufferUses

public static long getCharBufferUses()