Question

I’m writing a bit of JNI code where a DLL running in the process space of various processes on the system needs to talk back to a java process. I’ve decided to use named pipes to do this (for various reasons) after weighing up shared mem/sockets/rpc etc. My question is, is there a nice way of handling named pipes in Java or should I write one?

Answer 1

Assuming that you’re running on Unix, can’t you just create the pipe with exec and then read and write with a File*Stream?

@Test public void pipe() throws IOException, InterruptedException {
    Runtime.getRuntime().exec("mkfifo mypipe");

    final String[] read = new String[1];
    Thread t = new Thread() {
        @Override
        public void run() {
            try {
                BufferedReader r = new BufferedReader(new FileReader("mypipe"));
                read[0] = r.readLine();
            } catch (IOException e) {
            }
        }
    };
    t.start();

    FileWriter w = new FileWriter("mypipe");
    w.write("hello\n");
    w.flush();
    t.join();

    assertEquals("hello", read[0]);
}