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authorPaul Buetow <paul@buetow.org>2025-06-06 08:02:52 +0300
committerPaul Buetow <paul@buetow.org>2025-06-06 08:02:52 +0300
commit1d99762c7965d351510cfb5e08eac25e48d96038 (patch)
treef469493e911878ab9055ccf0494211bf9015922d /src/main/java/protocols/implementations/VSExternalTimeSyncProtocol.java
parent4d35597bd92607c4d194686e20b125044506c79a (diff)
Modernize project structure, update Maven config, move sources, add logging config, update README and .gitignore
Diffstat (limited to 'src/main/java/protocols/implementations/VSExternalTimeSyncProtocol.java')
-rw-r--r--src/main/java/protocols/implementations/VSExternalTimeSyncProtocol.java118
1 files changed, 118 insertions, 0 deletions
diff --git a/src/main/java/protocols/implementations/VSExternalTimeSyncProtocol.java b/src/main/java/protocols/implementations/VSExternalTimeSyncProtocol.java
new file mode 100644
index 0000000..f044861
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+++ b/src/main/java/protocols/implementations/VSExternalTimeSyncProtocol.java
@@ -0,0 +1,118 @@
+package protocols.implementations;
+
+import core.VSMessage;
+import protocols.VSAbstractProtocol;
+
+/**
+ * The class VSExternalTimeSyncProtocol, an implementation of the external
+ * time synchronisation protocol.
+ *
+ * @author Paul C. Buetow
+ */
+public class VSExternalTimeSyncProtocol extends VSAbstractProtocol {
+ /** The request time. */
+ private long requestTime;
+
+ /** The server is waiting for response, if true. */
+ private boolean waitingForResponse;
+
+ /**
+ * Instantiates a new external time sync protocol object.
+ */
+ public VSExternalTimeSyncProtocol() {
+ super(VSAbstractProtocol.HAS_ON_CLIENT_START);
+ setClassname(getClass().toString());
+ }
+
+ /* (non-Javadoc)
+ * @see events.VSAbstractProtocol#onClientInit()
+ */
+ public void onClientInit() {
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#onClientReset()
+ */
+ public void onClientReset() {
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#onClientStart()
+ */
+ public void onClientStart() {
+ requestTime = process.getTime();
+ waitingForResponse = true;
+
+ /* Multicast message to all processes */
+ VSMessage message = new VSMessage();
+ message.setBoolean("isClientRequest", true);
+ sendMessage(message);
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#onClientRecv(core.VSMessage)
+ */
+ public void onClientRecv(VSMessage recvMessage) {
+ if (!recvMessage.getBoolean("isServerResponse"))
+ return;
+
+ if (waitingForResponse)
+ waitingForResponse = false;
+ else
+ return;
+
+ long recvTime = process.getTime();
+ long roundTripTime = recvTime - requestTime;
+ long serverTime = recvMessage.getLong("time");
+ long newTime = serverTime + (long) (roundTripTime / 2);
+
+ log("Server time: " + serverTime + "; RTT: " + roundTripTime + "; Old time: " + recvTime + "; New time: " + newTime + "; Offset: " + (newTime - recvTime));
+
+ process.setTime(newTime);
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#onClientSchedule()
+ */
+ public void onClientSchedule() {
+ }
+
+ /* (non-Javadoc)
+ * @see events.VSAbstractProtocol#onServerInit()
+ */
+ public void onServerInit() {
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#onServerReset()
+ */
+ public void onServerReset() {
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#onServerRecv(core.VSMessage)
+ */
+ public void onServerRecv(VSMessage recvMessage) {
+ if (!recvMessage.getBoolean("isClientRequest"))
+ return;
+
+ /* Multicast message to all processes */
+ VSMessage message = new VSMessage();
+ message.setLong("time", process.getTime());
+ message.setBoolean("isServerResponse", true);
+ sendMessage(message);
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#onServerSchedule()
+ */
+ public void onServerSchedule() {
+ }
+
+ /* (non-Javadoc)
+ * @see protocols.VSAbstractProtocol#toString()
+ */
+ public String toString() {
+ return super.toString();
+ }
+}