Class OrderedMemoryAwareThreadPoolExecutor
- All Implemented Interfaces:
Executor
,ExecutorService
- Direct Known Subclasses:
OrderedDownstreamThreadPoolExecutor
MemoryAwareThreadPoolExecutor
which makes sure the events from the
same Channel
are executed sequentially.
NOTE: This thread pool inherits most characteristics of its super
type, so please make sure to refer to MemoryAwareThreadPoolExecutor
to understand how it works basically.
Event execution order
For example, let's say there are two executor threads that handle the events from the two channels:-------------------------------------> Timeline ------------------------------------> Thread X: --- Channel A (Event A1) --. .-- Channel B (Event B2) --- Channel B (Event B3) ---> \ / X / \ Thread Y: --- Channel B (Event B1) --' '-- Channel A (Event A2) --- Channel A (Event A3) --->As you see, the events from different channels are independent from each other. That is, an event of Channel B will not be blocked by an event of Channel A and vice versa, unless the thread pool is exhausted.
Also, it is guaranteed that the invocation will be made sequentially for the
events from the same channel. For example, the event A2 is never executed
before the event A1 is finished. (Although not recommended, if you want the
events from the same channel to be executed simultaneously, please use
MemoryAwareThreadPoolExecutor
instead.)
However, it is not guaranteed that the invocation will be made by the same thread for the same channel. The events from the same channel can be executed by different threads. For example, the Event A2 is executed by the thread Y while the event A1 was executed by the thread X.
Using a different key other than Channel
to maintain event order
OrderedMemoryAwareThreadPoolExecutor
uses a Channel
as a key
that is used for maintaining the event execution order, as explained in the
previous section. Alternatively, you can extend it to change its behavior.
For example, you can change the key to the remote IP of the peer:
public class RemoteAddressBasedOMATPE extendsPlease be very careful of memory leak of the child executor map. You must callOrderedMemoryAwareThreadPoolExecutor
{ ... Constructors ...@Override
protected ConcurrentMap<Object, Executor> newChildExecutorMap() { // The default implementation returns a special ConcurrentMap that // uses identity comparison only (seeIdentityHashMap
). // Because SocketAddress does not work with identity comparison, // we need to employ more generic implementation. return new ConcurrentHashMap<Object, Executor> } protected Object getChildExecutorKey(ChannelEvent
e) { // Use the IP of the remote peer as a key. return ((InetSocketAddress) e.getChannel().getRemoteAddress()).getAddress(); } // Make public so that you can call from anywhere. public boolean removeChildExecutor(Object key) { super.removeChildExecutor(key); } }
removeChildExecutor(Object)
when the life cycle of the key
ends (e.g. all connections from the same IP were closed.) Also, please
keep in mind that the key can appear again after calling removeChildExecutor(Object)
(e.g. a new connection could come in from the same old IP after removal.)
If in doubt, prune the old unused or stall keys from the child executor map
periodically:
RemoteAddressBasedOMATPE executor = ...; on every 3 seconds: for (Iterator<Object> i = executor.getChildExecutorKeySet().iterator; i.hasNext();) { InetAddress ip = (InetAddress) i.next(); if (there is no active connection from 'ip' now invalid input: '&'invalid input: '&' there has been no incoming connection from 'ip' for last 10 minutes) { i.remove(); } }If the expected maximum number of keys is small and deterministic, you could use a weak key map such as ConcurrentWeakHashMap or synchronized
WeakHashMap
instead of managing the life cycle of the
keys by yourself.-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected final class
Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor
ThreadPoolExecutor.AbortPolicy, ThreadPoolExecutor.CallerRunsPolicy, ThreadPoolExecutor.DiscardOldestPolicy, ThreadPoolExecutor.DiscardPolicy
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionOrderedMemoryAwareThreadPoolExecutor
(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize) Creates a new instance.OrderedMemoryAwareThreadPoolExecutor
(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize, long keepAliveTime, TimeUnit unit) Creates a new instance.OrderedMemoryAwareThreadPoolExecutor
(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize, long keepAliveTime, TimeUnit unit, ThreadFactory threadFactory) Creates a new instance.OrderedMemoryAwareThreadPoolExecutor
(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize, long keepAliveTime, TimeUnit unit, ObjectSizeEstimator objectSizeEstimator, ThreadFactory threadFactory) Creates a new instance. -
Method Summary
Modifier and TypeMethodDescriptionprotected void
Executes the specified task concurrently while maintaining the event order.protected Executor
protected Object
protected ConcurrentMap
<Object, Executor> (package private) void
onAfterExecute
(Runnable r, Throwable t) protected boolean
protected boolean
shouldCount
(Runnable task) Returnstrue
if and only if the specifiedtask
should be counted to limit the global and per-channel memory consumption.Methods inherited from class org.jboss.netty.handler.execution.MemoryAwareThreadPoolExecutor
beforeExecute, decreaseCounter, doUnorderedExecute, execute, getMaxChannelMemorySize, getMaxTotalMemorySize, getNotifyChannelFuturesOnShutdown, getObjectSizeEstimator, increaseCounter, remove, setMaxChannelMemorySize, setNotifyChannelFuturesOnShutdown, setObjectSizeEstimator, shutdownNow, shutdownNow, terminated
Methods inherited from class java.util.concurrent.ThreadPoolExecutor
afterExecute, allowCoreThreadTimeOut, allowsCoreThreadTimeOut, awaitTermination, finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getQueue, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, setCorePoolSize, setKeepAliveTime, setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, shutdown, toString
Methods inherited from class java.util.concurrent.AbstractExecutorService
invokeAll, invokeAll, invokeAny, invokeAny, newTaskFor, newTaskFor, submit, submit, submit
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Field Details
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childExecutors
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Constructor Details
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OrderedMemoryAwareThreadPoolExecutor
public OrderedMemoryAwareThreadPoolExecutor(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize) Creates a new instance.- Parameters:
corePoolSize
- the maximum number of active threadsmaxChannelMemorySize
- the maximum total size of the queued events per channel. Specify0
to disable.maxTotalMemorySize
- the maximum total size of the queued events for this pool Specify0
to disable.
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OrderedMemoryAwareThreadPoolExecutor
public OrderedMemoryAwareThreadPoolExecutor(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize, long keepAliveTime, TimeUnit unit) Creates a new instance.- Parameters:
corePoolSize
- the maximum number of active threadsmaxChannelMemorySize
- the maximum total size of the queued events per channel. Specify0
to disable.maxTotalMemorySize
- the maximum total size of the queued events for this pool Specify0
to disable.keepAliveTime
- the amount of time for an inactive thread to shut itself downunit
- theTimeUnit
ofkeepAliveTime
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OrderedMemoryAwareThreadPoolExecutor
public OrderedMemoryAwareThreadPoolExecutor(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize, long keepAliveTime, TimeUnit unit, ThreadFactory threadFactory) Creates a new instance.- Parameters:
corePoolSize
- the maximum number of active threadsmaxChannelMemorySize
- the maximum total size of the queued events per channel. Specify0
to disable.maxTotalMemorySize
- the maximum total size of the queued events for this pool Specify0
to disable.keepAliveTime
- the amount of time for an inactive thread to shut itself downunit
- theTimeUnit
ofkeepAliveTime
threadFactory
- theThreadFactory
of this pool
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OrderedMemoryAwareThreadPoolExecutor
public OrderedMemoryAwareThreadPoolExecutor(int corePoolSize, long maxChannelMemorySize, long maxTotalMemorySize, long keepAliveTime, TimeUnit unit, ObjectSizeEstimator objectSizeEstimator, ThreadFactory threadFactory) Creates a new instance.- Parameters:
corePoolSize
- the maximum number of active threadsmaxChannelMemorySize
- the maximum total size of the queued events per channel. Specify0
to disable.maxTotalMemorySize
- the maximum total size of the queued events for this pool Specify0
to disable.keepAliveTime
- the amount of time for an inactive thread to shut itself downunit
- theTimeUnit
ofkeepAliveTime
objectSizeEstimator
- theObjectSizeEstimator
of this poolthreadFactory
- theThreadFactory
of this pool
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Method Details
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newChildExecutorMap
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getChildExecutorKey
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getChildExecutorKeySet
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removeChildExecutor
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doExecute
Executes the specified task concurrently while maintaining the event order.- Overrides:
doExecute
in classMemoryAwareThreadPoolExecutor
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getChildExecutor
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shouldCount
Description copied from class:MemoryAwareThreadPoolExecutor
Returnstrue
if and only if the specifiedtask
should be counted to limit the global and per-channel memory consumption. To override this method, you must callsuper.shouldCount()
to make sure important tasks are not counted.- Overrides:
shouldCount
in classMemoryAwareThreadPoolExecutor
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onAfterExecute
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