Package org.jboss.netty.handler.ssl

Class SslBufferPool

java.lang.Object

org.jboss.netty.handler.ssl.SslBufferPool

public class SslBufferPool
extends Object

A ByteBuffer pool dedicated for SslHandler performance improvement.

In most cases, you won't need to create a new pool instance because SslHandler has a default pool instance internally.

The reason why SslHandler requires a buffer pool is because the current SSLEngine implementation always requires a 17KiB buffer for every 'wrap' and 'unwrap' operation. In most cases, the actual size of the required buffer is much smaller than that, and therefore allocating a 17KiB buffer for every 'wrap' and 'unwrap' operation wastes a lot of memory bandwidth, resulting in the application performance degradation.

Field Summary

Fields

Modifier and Type	Field	Description
private final boolean	allocateDirect
private static final int	DEFAULT_POOL_SIZE
private static final int	MAX_PACKET_SIZE_ALIGNED
private final int	maxBufferCount
private final AtomicInteger	numAllocations	The number of buffers allocated so far.
private final BlockingQueue<ByteBuffer>	pool
private final ByteBuffer	preallocated

Constructor Summary

Constructors

Constructor	Description
SslBufferPool()	Creates a new buffer pool whose size is 19267584, which can hold 1024 buffers.
SslBufferPool(boolean preallocate, boolean allocateDirect)	Creates a new buffer pool whose size is 19267584, which can hold 1024 buffers.
SslBufferPool(int maxPoolSize)	Creates a new buffer pool.
SslBufferPool(int maxPoolSize, boolean preallocate, boolean allocateDirect)	Creates a new buffer pool.

Method Summary

Modifier and Type	Method	Description
ByteBuffer	acquireBuffer()	Acquire a new ByteBuffer out of the SslBufferPool
private ByteBuffer	allocate(int capacity)
int	getMaxPoolSize()	Returns the maximum size of this pool in byte unit.
int	getUnacquiredPoolSize()	Returns the number of bytes which were allocated but have not been acquired yet.
void	releaseBuffer(ByteBuffer buffer)	Release a previous acquired ByteBuffer

Methods inherited from class java.lang.Object

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

Field Details

MAX_PACKET_SIZE_ALIGNED

private static final int MAX_PACKET_SIZE_ALIGNED

See Also:

• Constant Field Values

DEFAULT_POOL_SIZE

private static final int DEFAULT_POOL_SIZE

See Also:

• Constant Field Values

preallocated

private final ByteBuffer preallocated

pool

private final BlockingQueue<ByteBuffer> pool

maxBufferCount

private final int maxBufferCount

allocateDirect

private final boolean allocateDirect

numAllocations

private final AtomicInteger numAllocations

The number of buffers allocated so far. Used only when preallocated is null.

Constructor Details

SslBufferPool

public SslBufferPool()

Creates a new buffer pool whose size is 19267584, which can hold 1024 buffers.

SslBufferPool

public SslBufferPool(boolean preallocate,
 boolean allocateDirect)

Creates a new buffer pool whose size is 19267584, which can hold 1024 buffers.

Parameters:

preallocate - true if and only if the buffers in this pool has to be pre-allocated at construction time

allocateDirect - true if and only if this pool has to allocate direct buffers.

SslBufferPool

public SslBufferPool(int maxPoolSize)

Creates a new buffer pool.

Parameters:

maxPoolSize - the maximum number of bytes that this pool can hold

SslBufferPool

public SslBufferPool(int maxPoolSize,
 boolean preallocate,
 boolean allocateDirect)

Creates a new buffer pool.

Parameters:

maxPoolSize - the maximum number of bytes that this pool can hold

preallocate - true if and only if the buffers in this pool has to be pre-allocated at construction time

allocateDirect - true if and only if this pool has to allocate direct buffers.

Method Details

getMaxPoolSize

public int getMaxPoolSize()

Returns the maximum size of this pool in byte unit. The returned value can be somewhat different from what was specified in the constructor.

getUnacquiredPoolSize

public int getUnacquiredPoolSize()

Returns the number of bytes which were allocated but have not been acquired yet. You can estimate how optimal the specified maximum pool size is from this value. If it keeps returning 0, it means the pool is getting exhausted. If it keeps returns a unnecessarily big value, it means the pool is wasting the heap space.

acquireBuffer

public ByteBuffer acquireBuffer()

Acquire a new ByteBuffer out of the SslBufferPool

releaseBuffer

public void releaseBuffer(ByteBuffer buffer)

Release a previous acquired ByteBuffer

allocate

private ByteBuffer allocate(int capacity)