public class CachedBufferAllocator extends Object implements IoBufferAllocator
IoBufferAllocator
that caches the buffers which are likely to be reused during
auto-expansion of the buffers.
In SimpleBufferAllocator
, the underlying ByteBuffer
of the IoBuffer
is
reallocated on its capacity change, which means the newly allocated bigger ByteBuffer
replaces the old small ByteBuffer
. Consequently, the old ByteBuffer
is marked
for garbage collection.
It's not a problem in most cases as long as the capacity change doesn't happen frequently.
However, once it happens too often, it burdens the VM and the cost of filling the newly allocated
ByteBuffer
with NUL
surpass the cost of accessing the cache. In 2 dual-core
Opteron Italy 270 processors, CachedBufferAllocator
outperformed
SimpleBufferAllocator
in the following situation:
CachedBufferAllocator
uses ThreadLocal
to store the cached buffer, allocates
buffers whose capacity is power of 2 only and provides performance advantage if
IoBuffer.free()
is called properly.
Constructor and Description |
---|
CachedBufferAllocator()
Creates a new instance with the default parameters (#DEFAULT_MAX_POOL_SIZE and
#DEFAULT_MAX_CACHED_BUFFER_SIZE).
|
CachedBufferAllocator(int maxPoolSize,
int maxCachedBufferSize)
Creates a new instance.
|
Modifier and Type | Method and Description |
---|---|
IoBuffer |
allocate(int requestedCapacity,
boolean direct)
Returns the buffer which is capable of the specified size.
|
ByteBuffer |
allocateNioBuffer(int capacity,
boolean direct)
Returns the NIO buffer which is capable of the specified size.
|
void |
dispose()
Dispose of this allocator.
|
int |
getMaxCachedBufferSize()
Returns the maximum capacity of a cached buffer.
|
int |
getMaxPoolSize()
Returns the maximum number of buffers with the same capacity per thread.
|
IoBuffer |
wrap(ByteBuffer nioBuffer)
Wraps the specified NIO
ByteBuffer into MINA buffer. |
public CachedBufferAllocator()
public CachedBufferAllocator(int maxPoolSize, int maxCachedBufferSize)
maxPoolSize
- the maximum number of buffers with the same capacity per thread. 0
disables this limitation.maxCachedBufferSize
- the maximum capacity of a cached buffer. A buffer whose capacity is
bigger than this value is not pooled. 0 disables this limitation.public int getMaxPoolSize()
public int getMaxCachedBufferSize()
public IoBuffer allocate(int requestedCapacity, boolean direct)
IoBufferAllocator
allocate
in interface IoBufferAllocator
requestedCapacity
- the capacity of the bufferdirect
- true to get a direct buffer, false to get a heap buffer.public ByteBuffer allocateNioBuffer(int capacity, boolean direct)
IoBufferAllocator
allocateNioBuffer
in interface IoBufferAllocator
capacity
- the capacity of the bufferdirect
- true to get a direct buffer, false to get a heap buffer.public IoBuffer wrap(ByteBuffer nioBuffer)
IoBufferAllocator
ByteBuffer
into MINA buffer.wrap
in interface IoBufferAllocator
public void dispose()
IoBufferAllocator
dispose
in interface IoBufferAllocator
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