1 files changed, 126 insertions, 0 deletions
diff --git a/sources/protocols/BerkelyTimeProtocol.java b/sources/protocols/BerkelyTimeProtocol.java
new file mode 100644
index 0000000..ea81cba
--- /dev/null
+++ b/sources/protocols/BerkelyTimeProtocol.java
@@ -0,0 +1,126 @@
+package protocols;
+
+import prefs.VSPrefs;
+import core.VSMessage;
+
+import java.util.HashMap;
+
+public class BerkelyTimeProtocol extends VSProtocol {
+    /* Berkely Server variables */
+
+    /* Integer: Process ID, Long: Local time of the process */
+    private HashMap<Integer,Long> processTimes = new HashMap<Integer,Long>();
+    /* Integer: Process ID, Long: Time of receiving the response from the process */
+    private HashMap<Integer,Long> recvTimes = new HashMap<Integer,Long>();
+    /* Integer: Process ID, Long: Calculated process times (using the RTT) */
+    private HashMap<Integer,Long> realTimesRTT = new HashMap<Integer,Long>();
+    /* Time the request/response has started */
+    private long requestTime;
+
+    /* Berkely Client vairables */
+
+    protected void onInit() {
+        setProtocolClassname(getClass().toString());
+
+        /* Those prefs are editable through the VSProtocol VSEditor GUI. t_min and t_max in milliseconds  */
+        setInteger("numProcesses", getNumProcesses()-1);
+    }
+
+    protected void onClientReset() {
+        processTimes.clear();
+        recvTimes.clear();
+        realTimesRTT.clear();
+    }
+
+    protected void onClientStart() {
+        requestTime = process.getTime();
+        VSMessage message = new VSMessage(getProtocolClassname());
+        message.setBoolean("isRequest", true);
+        sendMessage(message);
+    }
+
+    protected void onClientRecv(VSMessage recvMessage) {
+        /* Ignore all protocol messages which are not a response message, e.g. itself */
+        if (!recvMessage.getBoolean("isResponse"))
+            return;
+
+        Integer processID = new Integer(recvMessage.getInteger("processID"));
+        Long time = new Long(recvMessage.getLong("time"));
+
+        processTimes.put(processID, time);
+        recvTimes.put(processID, new Long(process.getTime()));
+
+        /* All processes have comitted the response */
+        if (processTimes.size() == getInteger("numProcesses")) {
+            long avgTime = calculateAverageTime();
+            /* Set the local's process time to the new avg reference time */
+            process.setTime(avgTime);
+            /* Tell all other processes what to do in order to justify their times */
+            sendJustifyRequests(avgTime);
+			/* Start "clean" next time */
+			onClientReset();
+        }
+    }
+
+    /**
+     * Calculate the new average time
+     */
+    private long calculateAverageTime() {
+        long sum = 0;
+        for (Integer processID : processTimes.keySet()) {
+            Long localTime = processTimes.get(processID);
+            Long recvTime = recvTimes.get(processID);
+            long rtt = recvTime.longValue() - requestTime;
+            long realProcessTime = localTime + (long) (rtt / 2);
+            realTimesRTT.put(processID, new Long(realProcessTime));
+            sum += realProcessTime;
+        }
+        /* Include the time of the local process */
+        sum += process.getTime();
+        return (long) sum / (1 + getInteger("numProcesses"));
+    }
+
+    /**
+     * Sends to all clients a value to justify their local clocks
+     */
+    private void sendJustifyRequests(long avgTime) {
+        for (Integer processID : processTimes.keySet()) {
+            long realProcessTime = realTimesRTT.get(processID).longValue();
+            long diff = avgTime - realProcessTime;
+            VSMessage message = new VSMessage(getProtocolClassname());
+            message.setBoolean("isJustify", true);
+            message.setLong("timeDiff", diff);
+            message.setInteger("receiverProcessID", processID);
+			sendMessage(message);
+        }
+    }
+
+    protected void onServerReset() {
+    }
+
+    protected void onServerRecv(VSMessage recvMessage) {
+        if (recvMessage.getBoolean("isRequest")) {
+            VSMessage message = new VSMessage(getProtocolClassname());
+            message.setInteger("processID", process.getProcessID());
+            message.setLong("time", process.getTime());
+            message.setBoolean("isResponse", true);
+			sendMessage(message);
+
+        } else if (recvMessage.getBoolean("isJustify")) {
+            /* Check if it's "my" justify message */
+            if (recvMessage.getInteger("receiverProcessID") != process.getProcessID()) 
+                return;
+
+            long timeDiff = recvMessage.getLong("timeDiff");
+            long recvTime = process.getTime();
+            long newTime = process.getTime() + timeDiff;
+			logg("Neue Zeit: " + newTime);
+
+            process.setTime(newTime);
+        }
+    }
+
+    public String toString() {
+        return super.toString();
+    }
+}