| /* |
| * Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| /* |
| * |
| * |
| * An "echo" service designed to be used with inetd. It can be configured in |
| * inetd.conf to be used by any of the following types of services :- |
| * |
| * stream tcp nowait |
| * stream tcp6 nowait |
| * stream tcp wait |
| * stream tcp6 wait |
| * dgram udp wait |
| * dgram udp6 wait |
| * |
| * If configured as a "tcp nowait" service then inetd will launch a |
| * VM to run the EchoService each time that a client connects to |
| * the TCP port. The EchoService simply echos any messages it |
| * receives from the client and shuts if the client closes the |
| * connection. |
| * |
| * If configured as a "tcp wait" service then inetd will launch a VM |
| * to run the EchoService when a client connects to the port. When |
| * launched the EchoService takes over the listener socket. It |
| * terminates when all clients have disconnected and the service |
| * is idle for a few seconds. |
| * |
| * If configured as a "udp wait" service then a VM will be launched for |
| * each UDP packet to the configured port. System.inheritedChannel() |
| * will return a DatagramChannel. The echo service here will terminate after |
| * echoing the UDP packet back to the client. |
| * |
| * The service closes the inherited network channel when complete. To |
| * facilate testing that the channel is closed the "tcp nowait" service |
| * can close the connection after a given number of bytes. |
| */ |
| import java.nio.*; |
| import java.nio.channels.*; |
| import java.io.IOException; |
| import java.net.*; |
| |
| public class EchoService { |
| |
| private static void doIt(SocketChannel sc, int closeAfter, int delay) throws IOException { |
| ByteBuffer bb = ByteBuffer.allocate(1024); |
| int total = 0; |
| for (;;) { |
| bb.clear(); |
| int n = sc.read(bb); |
| if (n < 0) { |
| break; |
| } |
| total += n; |
| |
| // echo |
| bb.flip(); |
| sc.write(bb); |
| |
| // close after X bytes? |
| if (closeAfter > 0 && total >= closeAfter) { |
| break; |
| } |
| } |
| |
| sc.close(); |
| if (delay > 0) { |
| try { |
| Thread.currentThread().sleep(delay); |
| } catch (InterruptedException x) { } |
| } |
| } |
| |
| private static void doIt(DatagramChannel dc) throws IOException { |
| ByteBuffer bb = ByteBuffer.allocate(1024); |
| SocketAddress sa = dc.receive(bb); |
| bb.flip(); |
| dc.send(bb, sa); |
| dc.close(); |
| } |
| |
| |
| // A worker thread to service a single connection |
| // The class maintains a count of the number of worker threads so |
| // can the service can terminate then all clients disconnect. |
| |
| static class Worker implements Runnable { |
| private static int count = 0; |
| private static Object lock = new Object(); |
| |
| public static int count() { |
| synchronized (lock) { |
| return count; |
| } |
| } |
| |
| private SocketChannel sc; |
| |
| Worker(SocketChannel sc) { |
| this.sc = sc; |
| synchronized (lock) { |
| count++; |
| } |
| } |
| |
| public void run() { |
| try { |
| doIt(sc, -1, -1); |
| } catch (IOException x) { |
| } finally { |
| synchronized (lock) { |
| count--; |
| } |
| } |
| |
| } |
| } |
| |
| public static void main(String args[]) throws IOException { |
| Channel c = System.inheritedChannel(); |
| if (c == null) { |
| return; |
| } |
| |
| // tcp nowait |
| if (c instanceof SocketChannel) { |
| int closeAfter = 0; |
| int delay = 0; |
| if (args.length > 0) { |
| closeAfter = Integer.parseInt(args[0]); |
| } |
| if (args.length > 1) { |
| delay = Integer.parseInt(args[1]); |
| } |
| doIt((SocketChannel)c, closeAfter, delay); |
| } |
| |
| // tcp wait - in this case we take over the listener socket |
| // In this test case we create a thread to service each connection |
| // and terminate after all clients are gone. |
| // |
| if (c instanceof ServerSocketChannel) { |
| ServerSocketChannel ssc = (ServerSocketChannel)c; |
| |
| ssc.configureBlocking(false); |
| Selector sel = ssc.provider().openSelector(); |
| SelectionKey sk = ssc.register(sel, SelectionKey.OP_ACCEPT); |
| SocketChannel sc; |
| int count = 0; |
| for (;;) { |
| sel.select(5000); |
| if (sk.isAcceptable() && ((sc = ssc.accept()) != null)) { |
| Worker w = new Worker(sc); |
| (new Thread(w)).start(); |
| } else { |
| // if all clients have disconnected then we die as well. |
| if (Worker.count() == 0) { |
| break; |
| } |
| } |
| } |
| ssc.close(); |
| } |
| |
| // udp wait |
| if (c instanceof DatagramChannel) { |
| doIt((DatagramChannel)c); |
| } |
| |
| // linger? |
| if (args.length > 0) { |
| int delay = Integer.parseInt(args[0]); |
| try { |
| Thread.currentThread().sleep(delay); |
| } catch (InterruptedException x) { } |
| } |
| |
| } |
| |
| } |