This commit introduces a new API for ByteBuf allocation which fixes
issue #643 along with refactoring of ByteBuf for simplicity and better
performance. (see #62)
A user can configure the ByteBufAllocator of a Channel via
ChannelOption.ALLOCATOR or ChannelConfig.get/setAllocator(). The
default allocator is currently UnpooledByteBufAllocator.HEAP_BY_DEFAULT.
To allocate a buffer, do not use Unpooled anymore. do the following:
ctx.alloc().buffer(...); // allocator chooses the buffer type.
ctx.alloc().heapBuffer(...);
ctx.alloc().directBuffer(...);
To deallocate a buffer, use the unsafe free() operation:
((UnsafeByteBuf) buf).free();
The following is the list of the relevant changes:
- Add ChannelInboundHandler.freeInboundBuffer() and
ChannelOutboundHandler.freeOutboundBuffer() to let a user free the
buffer he or she allocated. ChannelHandler adapter classes implement
is already, so most users won't need to call free() by themselves.
freeIn/OutboundBuffer() methods are invoked when a Channel is closed
and deregistered.
- All ByteBuf by contract must implement UnsafeByteBuf. To access an
unsafe operation: ((UnsafeByteBuf) buf).internalNioBuffer()
- Replace WrappedByteBuf and ByteBuf.Unsafe with UnsafeByteBuf to
simplify overall class hierarchy and to avoid unnecesary instantiation
of Unsafe instances on an unsafe operation.
- Remove buffer reference counting which is confusing
- Instantiate SwappedByteBuf lazily to avoid instantiation cost
- Rename ChannelFutureFactory to ChannelPropertyAccess and move common
methods between Channel and ChannelHandlerContext there. Also made it
package-private to hide it from a user.
- Remove unused unsafe operations such as newBuffer()
- Add DetectionUtil.canFreeDirectBuffer() so that an allocator decides
which buffer type to use safely
First cut at implementing a generic abstraction layer for pluggable
metrics providers. This first cut is closely modeled after Yammer
Metrics. It remains to be seen if it is indeed flexibel enough to
support other providers.
Provide a default implementation of this new abstraction layer
based on Yammer Metrics.
Support pluggable Monitoring Providers using Java 6's ServiceLoader.
Use this new abstraction layer to provide stats on (a) number of
Timeouts executed per second and (b) distribution of absolute
deviation between scheduled and actual Timeout execution time in
HashedWheelTimer.
* Interface ValueDistributionMonitor, a monitor for histograms.
* Interface EventRateMonitor, a monitor for measuring the rate per time
unit of specific events.
* Interface ValueMonitor, a monitor for tracking an arbitrary datum's
current value
* Interface CounterMonitor, a monitor for incrementing/decrementing a
long value
* Interface MonitorRegistry, a registry for monitors that serves as the
interface between Netty and concrete metrics providers as e.g. Yammer
Metrics.
* Interface MonitorRegistryFactory, to be implemented by metrics
providers.
* Document how to use Netty's new monitoring support in javadocs for
package io.netty.monitor.
