>From the top of my head (I'm in a bus atm), each session has its own chain of filter, thus its own instance. The variable is not shared, and the session is always handled by the same IoPricessor, so the same thread. That should be thread safe unless you start doing weird things with an executor. Le 16 août 2014 18:06, "Kai ZHANG" <[email protected]> a écrit :
> Hi, > > I am a beginer of Mina. I read the api doc located at: > > /http://mina.apache.org/mina-project/apidocs/org/apache/ > mina/core/session/IoSession.html/ > > It says that IoSession is thread-safe. > > But when I read the source of mina trunk branch. I found the > IoSession.write() method may be not thread-safe. The java source file is : > > /./core/src/main/java/org/apache/mina/session/AbstractIoSession.java/ > > Here is the method calling chain: > AbstractIoSession.write() > -> AbstractIoSession.doWriteWithFuture > -> AbstractIoSession.processMessageWriting() > -> AbstractIoFilter.messageWriting() > -> AbstractIoSession.callWriteNextFilter() > > The code which is thread-safe reside in > AbstractIoSession.callWriteNextFilter(), > here is the code: > > /** > * process session message received event using the filter > chain. To be called by the session {@link SelectorLoop} . > * > * @param message the received message > */ > @Override > public void callWriteNextFilter(WriteRequest message) { > if (IS_DEBUG) { > LOG.debug("calling next filter for writing for message > '{}' position : {}", message, writeChainPosition); > } > > /writeChainPosition--;/ > > if (writeChainPosition < 0 || chain.length == 0) { > // end of chain processing > enqueueWriteRequest(message); > } else { > chain[writeChainPosition].messageWriting(this, message, > this); > } > > /writeChainPosition++;/ > } > > Here the variable "writeChainPosition" is not thread-safe, If more than > one thread call IoSession.write() concurrently, the "writeChainPosition" > may have race condition. > > The result is some of the IoFilter may be skipped or called twice, and the > message data passed down the filter chain may be broken. > > Could you tell me if my understanding is correct? > > Is IoSession.write() method designed to be thread-safe or should I use a > lock for every concurrent IoSession.write() operation? > > > > >
