From acfad4df4de30ba83d7c44c9e0d672723736b257 Mon Sep 17 00:00:00 2001
From: senft-lap <senftt@gmail.com>
Date: Tue, 20 Nov 2012 15:06:21 +0100
Subject: [PATCH] .receive() is now non-blocking, in order to terminate the
 listen thread

---
 ws2012/P2P/uebungen/4/src/peer/Node.java | 159 +++++++++++++----------
 1 file changed, 88 insertions(+), 71 deletions(-)

diff --git a/ws2012/P2P/uebungen/4/src/peer/Node.java b/ws2012/P2P/uebungen/4/src/peer/Node.java
index 55191212..4fc87ff2 100644
--- a/ws2012/P2P/uebungen/4/src/peer/Node.java
+++ b/ws2012/P2P/uebungen/4/src/peer/Node.java
@@ -26,13 +26,15 @@ public class Node {
 
 	private List<SocketAddress> neighbors = new ArrayList<SocketAddress>();
 
-	private Thread thread;
+	private volatile Thread thread;
 	private UDPListen udpListen;
 
 	public Node() {
 		try {
 			channel = DatagramChannel.open();
 			channel.socket().bind(null);
+			channel.configureBlocking(false);
+
 			buf = ByteBuffer.allocate(BUF_SIZE);
 
 			this.name = channel.socket().getLocalSocketAddress().toString();
@@ -189,86 +191,101 @@ public class Node {
 
 		public void run() {
 			StringBuilder sb_received;
+
 			while (running) {
 				SocketAddress receivedFrom = null;
 				buf.clear();
 
 				try {
 					receivedFrom = channel.receive(buf);
+
+					if (buf.remaining() != 512) {
+						buf.flip();
+
+						byte messageType = buf.get();
+
+						switch (messageType) {
+						case MessageType.INVITE:
+							LOGGER.info(name + " received invite from "
+									+ receivedFrom.toString());
+							neighbors.add(receivedFrom);
+							break;
+
+						case MessageType.LEAVE:
+							LOGGER.info(receivedFrom.toString()
+									+ " is leaving. Deleting...");
+							neighbors.remove(receivedFrom);
+							break;
+
+						case MessageType.NEW_NEIGHBOR_IPV4:
+							LOGGER.info(name + " received new IPV4 neighbor"
+									+ receivedFrom.toString() + ": "
+									+ new String(buf.array()));
+
+							byte[] byte_addr = new byte[7];
+
+							// Read 4 Bytes and 1 Int
+							for (int i = 0; i < 8; i = i + 2) {
+								byte_addr[i] = buf.get();
+								if (i < 7)
+									byte_addr[i + 1] = '.';
+							}
+
+							int port = buf.getInt();
+
+							neighbors.add(new InetSocketAddress(new String(
+									byte_addr), port));
+
+							// TODO: send PING to new neighbor and expect wait
+							// to
+							// get a
+							// PONG
+
+							break;
+						case MessageType.NEW_NEIGHBOR_IPV6:
+							LOGGER.info(name
+									+ " received new IPV6 neighbor from: "
+									+ receivedFrom.toString() + ": "
+									+ new String(buf.array()));
+
+							sb_received = new StringBuilder(512);
+							while (buf.hasRemaining()) {
+								sb_received.append((char) buf.get());
+							}
+
+							String str_received = sb_received.toString();
+
+							int startOfPort = str_received.lastIndexOf(":");
+
+							String new_hostname = str_received.substring(1,
+									startOfPort);
+							int new_port = Integer.valueOf(str_received
+									.substring(startOfPort + 1));
+
+							SocketAddress new_neighbor = new InetSocketAddress(
+									new_hostname, new_port);
+							neighbors.add(new_neighbor);
+
+							break;
+
+						default:
+							LOGGER.info(name
+									+ " received unknown command from "
+									+ receivedFrom.toString() + ": "
+									+ new String(buf.array()));
+						}
+					} else {
+						try {
+							Thread.sleep(10);
+						} catch (InterruptedException e) {
+							// TODO Auto-generated catch block
+							e.printStackTrace();
+						}
+					}
 				} catch (IOException e) {
 					e.printStackTrace();
 				}
 
-				buf.flip();
-
-				byte messageType = buf.get();
-
-				switch (messageType) {
-				case MessageType.INVITE:
-					LOGGER.info(name + " received invite from "
-							+ receivedFrom.toString());
-					neighbors.add(receivedFrom);
-					break;
-
-				case MessageType.LEAVE:
-					LOGGER.info(receivedFrom.toString()
-							+ " is leaving. Deleting...");
-					neighbors.remove(receivedFrom);
-					break;
-
-				case MessageType.NEW_NEIGHBOR_IPV4:
-					LOGGER.info(name + " received new IPV4 neighbor"
-							+ receivedFrom.toString() + ": "
-							+ new String(buf.array()));
-
-					byte[] byte_addr = new byte[7];
-
-					// Read 4 Bytes and 1 Int
-					for (int i = 0; i < 8; i = i + 2) {
-						byte_addr[i] = buf.get();
-						if (i < 7)
-							byte_addr[i + 1] = '.';
-					}
-
-					int port = buf.getInt();
-
-					neighbors.add(new InetSocketAddress(new String(byte_addr),
-							port));
-
-					// TODO: send PING to new neighbor and expect wait to get a
-					// PONG
-
-					break;
-				case MessageType.NEW_NEIGHBOR_IPV6:
-					LOGGER.info(name + " received new IPV6 neighbor from: "
-							+ receivedFrom.toString() + ": "
-							+ new String(buf.array()));
-
-					sb_received = new StringBuilder(512);
-					while (buf.hasRemaining()) {
-						sb_received.append((char) buf.get());
-					}
-
-					String str_received = sb_received.toString();
-
-					int startOfPort = str_received.lastIndexOf(":");
-
-					String new_hostname = str_received
-							.substring(1, startOfPort);
-					int new_port = Integer.valueOf(str_received
-							.substring(startOfPort + 1));
-
-					SocketAddress new_neighbor = new InetSocketAddress(
-							new_hostname, new_port);
-					neighbors.add(new_neighbor);
-
-					break;
-
-				default:
-					LOGGER.info(name + " received unknown command from "
-							+ receivedFrom.toString() + ": "
-							+ new String(buf.array()));
-				}
 			}
 		}