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POJava: Are concurrent reads and writes possible on a blocking SocketChannel via Object(In|Out)putStreams?
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  1. POJava: Are concurrent reads and writes possible on a blocking SocketChannel via Object(In|Out)putStreams?
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    copied!<p>I created an <code>ObjectInputSteam</code> and <code>ObjectOutputStream</code> on a blocking <code>SocketChannel</code> and am trying to read and write concurrently. My code is something like this:</p> <pre><code>socketChannel = SocketChannel.open(destNode); objectOutputStream = new ObjectOutputStream(Channels.newOutputStream(socketChannel)); objectInputStream = new ObjectInputStream(Channels.newInputStream(socketChannel)); Thread replyThread = new Thread("SendRunnable-ReplyThread") { @Override public void run() { try { byte reply = objectInputStream.readByte();//(A) //..process reply } catch (Throwable e) { logger.warn("Problem reading receive reply.", e); } } }; replyThread.start(); objectOutputStream.writeObject(someObject);//(B) //..more writing </code></pre> <p>Problem is the write at line (B) blocks until the read at line (A) completes (blocks on the object returned by <code>SelectableChannel#blockingLock()</code> ). But app logic dictates that the read will not complete until all the writes complete, so we have an effective deadlock.</p> <p><code>SocketChannel</code> javadocs say that concurrent reads and writes are supported.</p> <p>I experienced no such problem when I tried a regular Socket solution:</p> <pre><code>Socket socket = new Socket(); socket.connect(destNode); final OutputStream outputStream = socket.getOutputStream(); objectOutputStream = new ObjectOutputStream(outputStream); objectInputStream = new ObjectInputStream(socket.getInputStream()); </code></pre> <p>However, then I cannot take advantage of the performance benefits of <code>FileChannel#transferTo(...)</code></p>
 

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