java.lang.Object | |
↳ | org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor |
Known Direct Subclasses |
Generic implementation of IOReactor
that can run multiple
BaseIOReactor
instance in separate worker threads and distribute
newly created I/O session equally across those I/O reactors for a more
optimal resource utilization and a better I/O performance. Usually it is
recommended to have one worker I/O reactor per physical CPU core.
Important note about exception handling
Protocol specific exceptions as well as those I/O exceptions thrown in the course of interaction with the session's channel are to be expected are to be dealt with by specific protocol handlers. These exceptions may result in termination of an individual session but should not affect the I/O reactor and all other active sessions. There are situations, however, when the I/O reactor itself encounters an internal problem such as an I/O exception in the underlying NIO classes or an unhandled runtime exception. Those types of exceptions are usually fatal and will cause the I/O reactor to shut down automatically.
There is a possibility to override this behavior and prevent I/O reactors
from shutting down automatically in case of a runtime exception or an I/O
exception in internal classes. This can be accomplished by providing a custom
implementation of the IOReactorExceptionHandler
interface.
If an I/O reactor is unable to automatically recover from an I/O or a runtime
exception it will enter the shutdown mode. First off, it cancel all pending
new session requests. Then it will attempt to close all active I/O sessions
gracefully giving them some time to flush pending output data and terminate
cleanly. Lastly, it will forcibly shut down those I/O sessions that still
remain active after the grace period. This is a fairly complex process, where
many things can fail at the same time and many different exceptions can be
thrown in the course of the shutdown process. The I/O reactor will record all
exceptions thrown during the shutdown process, including the original one
that actually caused the shutdown in the first place, in an audit log. One
can obtain the audit log using getAuditLog()
, examine exceptions
thrown by the I/O reactor prior and in the course of the reactor shutdown
and decide whether it is safe to restart the I/O reactor.
The following parameters can be used to customize the behavior of this class:
Fields | |||||||||||
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auditLog | |||||||||||
exceptionHandler | |||||||||||
interestOpsQueueing | |||||||||||
params | |||||||||||
selectTimeout | |||||||||||
selector | |||||||||||
status |
Public Constructors | |||||||||||
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Creates an instance of AbstractMultiworkerIOReactor.
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Public Methods | |||||||||||
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Activates the main I/O reactor as well as all worker I/O reactors.
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Returns the audit log containing exceptions thrown by the I/O reactor
prior and in the course of the reactor shutdown.
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Returns the current status of the reactor.
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Sets exception handler for this I/O reactor.
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Initiates shutdown of the reactor and blocks approximately for the given
period of time in milliseconds waiting for the reactor to terminate all
active connections, to shut down itself and to release system resources
it currently holds.
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Initiates shutdown of the reactor and blocks for a default period of
time waiting for the reactor to terminate all active connections, to shut
down itself and to release system resources it currently holds.
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Protected Methods | |||||||||||
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Assigns the given channel entry to one of the worker I/O reactors.
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Adds the given
Throwable object with the given time stamp
to the audit log. | |||||||||||
Adds the given
Throwable object to the audit log. | |||||||||||
Blocks for the given period of time in milliseconds awaiting
the completion of the reactor shutdown.
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Triggered to cancel pending session requests.
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Activates the shutdown sequence for this reactor.
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Prepares the given Socket by resetting some of its properties.
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Triggered to process I/O events registered by the main Selector.
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Registers the given channel with the main Selector.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
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From interface
org.apache.http.nio.reactor.IOReactor
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Creates an instance of AbstractMultiworkerIOReactor.
workerCount | number of worker I/O reactors. |
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threadFactory | the factory to create threads.
Can be null . |
params | HTTP parameters. |
IOReactorException | in case if a non-recoverable I/O error. |
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Activates the main I/O reactor as well as all worker I/O reactors.
The I/O main reactor will start reacting to I/O events and triggering
notification methods. The worker I/O reactor in their turn will start
reacting to I/O events and dispatch I/O event notifications to the given
IOEventDispatch
interface.
This method will enter the infinite I/O select loop on the Selector instance associated with this I/O reactor and used to manage creation of new I/O channels. Once a new I/O channel has been created the processing of I/O events on that channel will be delegated to one of the worker I/O reactors.
The method will remain blocked unto the I/O reactor is shut down or the execution thread is interrupted.
eventDispatch | the I/O event dispatch. |
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InterruptedIOException | if the dispatch thread is interrupted. |
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IOReactorException | in case if a non-recoverable I/O error. |
Returns the audit log containing exceptions thrown by the I/O reactor prior and in the course of the reactor shutdown.
Returns the current status of the reactor.
Sets exception handler for this I/O reactor.
exceptionHandler | the exception handler. |
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Initiates shutdown of the reactor and blocks approximately for the given period of time in milliseconds waiting for the reactor to terminate all active connections, to shut down itself and to release system resources it currently holds.
waitMs | wait time in milliseconds. |
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IOException |
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Initiates shutdown of the reactor and blocks for a default period of time waiting for the reactor to terminate all active connections, to shut down itself and to release system resources it currently holds. It is up to individual implementations to decide for how long this method can remain blocked.
IOException |
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Assigns the given channel entry to one of the worker I/O reactors.
entry | the channel entry. |
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Adds the given Throwable
object with the given time stamp
to the audit log.
ex | the exception thrown by the I/O reactor. |
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timestamp | the time stamp of the exception. Can be
null in which case the current date / time will be used.
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Adds the given Throwable
object to the audit log.
ex | the exception thrown by the I/O reactor. |
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Blocks for the given period of time in milliseconds awaiting
the completion of the reactor shutdown. If the value of
timeout
is set to 0
this method blocks
indefinitely.
timeout | the maximum wait time. |
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InterruptedException | if interrupted. |
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Triggered to cancel pending session requests.
Super-classes can implement this method to react to the event.
IOReactorException | in case if a non-recoverable I/O error. |
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Activates the shutdown sequence for this reactor. This method will cancel all pending session requests, close out all active I/O channels, make an attempt to terminate all worker I/O reactors gracefully, and finally force-terminate those I/O reactors that failed to terminate after the specified grace period.
InterruptedIOException | if the shutdown sequence has been interrupted. |
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Prepares the given Socket by resetting some of its properties.
socket | the socket |
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IOException | in case of an I/O error. |
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Triggered to process I/O events registered by the main Selector.
Super-classes can implement this method to react to the event.
count | event count. |
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IOReactorException | in case if a non-recoverable I/O error. |
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Registers the given channel with the main Selector.
channel | the channel. |
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ops | interest ops. |
ClosedChannelException | if the channel has been already closed. |
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