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Diffstat (limited to 'src/main/java/examples/CreateSimpleRaftSimulation.java')
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diff --git a/src/main/java/examples/CreateSimpleRaftSimulation.java b/src/main/java/examples/CreateSimpleRaftSimulation.java new file mode 100644 index 0000000..278824d --- /dev/null +++ b/src/main/java/examples/CreateSimpleRaftSimulation.java @@ -0,0 +1,122 @@ +package examples; + +import simulator.*; +import core.*; +import prefs.*; +import events.*; +import events.internal.*; +import events.implementations.*; +import serialize.VSSerialize; +import java.io.*; + +/** + * Creates a simple working Raft simulation. + * The key insight: Raft protocol uses HAS_ON_SERVER_START, so servers + * automatically start when activated. We just need to activate them! + */ +public class CreateSimpleRaftSimulation { + + private static final String RAFT_PROTOCOL = "protocols.implementations.VSRaftProtocol"; + + public static void main(String[] args) throws Exception { + // Initialize + VSDefaultPrefs prefs = new VSDefaultPrefs(); + prefs.fillWithDefaults(); + VSRegisteredEvents.init(prefs); + + // Create frame and simulator + VSSimulatorFrame frame = new VSSimulatorFrame(prefs, null); + VSSimulator simulator = new VSSimulator(prefs, frame); + frame.addSimulator(simulator); + + // Access visualization via reflection + java.lang.reflect.Field vizField = VSSimulator.class.getDeclaredField("simulatorVisualization"); + vizField.setAccessible(true); + VSSimulatorVisualization viz = (VSSimulatorVisualization) vizField.get(simulator); + + // Add more processes - we want 5 total (3 servers, 2 clients) + while (viz.getNumProcesses() < 5) { + java.lang.reflect.Method addProcessMethod = VSSimulatorVisualization.class.getDeclaredMethod("addProcess"); + addProcessMethod.setAccessible(true); + addProcessMethod.invoke(viz); + } + + VSTaskManager taskManager = viz.getTaskManager(); + + // Activate Raft SERVERS on processes 0, 1, 2 + // Since Raft uses HAS_ON_SERVER_START, onServerStart() will be called automatically! + System.out.println("Creating Raft server activations..."); + for (int i = 0; i < 3; i++) { + VSProtocolEvent serverEvent = new VSProtocolEvent(); + serverEvent.setProtocolClassname(RAFT_PROTOCOL); + serverEvent.isClientProtocol(false); // Server mode + serverEvent.isProtocolActivation(true); // Activation + + // Activate at time 0 + VSTask task = new VSTask(0, viz.getProcess(i), serverEvent, false); + taskManager.addTask(task); + System.out.println(" - Server " + i + " will activate at time 0"); + } + + // Activate Raft CLIENTS on processes 3, 4 + // Clients will react to server heartbeats and start sending requests + System.out.println("\nCreating Raft client activations..."); + for (int i = 3; i < 5; i++) { + VSProtocolEvent clientEvent = new VSProtocolEvent(); + clientEvent.setProtocolClassname(RAFT_PROTOCOL); + clientEvent.isClientProtocol(true); // Client mode + clientEvent.isProtocolActivation(true); // Activation + + // Activate clients a bit later so servers have time to elect leader + VSTask task = new VSTask(300 + (i-3)*100, viz.getProcess(i), clientEvent, false); + taskManager.addTask(task); + System.out.println(" - Client " + (i-3) + " will activate at time " + (300 + (i-3)*100)); + } + + // Add crash/recovery to demonstrate leader re-election + System.out.println("\nAdding failure scenarios..."); + + // Crash server 0 at time 1000 + VSProcessCrashEvent crash = new VSProcessCrashEvent(); + VSTask crashTask = new VSTask(1000, viz.getProcess(0), crash, false); + taskManager.addTask(crashTask); + System.out.println(" - Server 0 will crash at time 1000"); + + // Recover server 0 at time 1500 + VSProcessRecoverEvent recover = new VSProcessRecoverEvent(); + VSTask recoverTask = new VSTask(1500, viz.getProcess(0), recover, false); + taskManager.addTask(recoverTask); + System.out.println(" - Server 0 will recover at time 1500"); + + // Save simulation + File outputFile = new File("saved-simulations/raft-simple.dat"); + outputFile.getParentFile().mkdirs(); + + VSSerialize serialize = new VSSerialize(); + serialize.saveSimulator(outputFile.getAbsolutePath(), simulator); + + frame.dispose(); + + System.out.println("\n==========================================="); + System.out.println("Simple Raft simulation saved successfully!"); + System.out.println("==========================================="); + System.out.println("\nFile: " + outputFile.getAbsolutePath()); + System.out.println("\nWhat happens in this simulation:"); + System.out.println("1. Time 0: Three Raft servers start and begin leader election"); + System.out.println("2. Time ~150-300: One server becomes leader (watch for election messages)"); + System.out.println("3. Time 300: First client activates and starts sending requests"); + System.out.println("4. Time 400: Second client activates and starts sending requests"); + System.out.println("5. Time 1000: Server 0 crashes, triggering new leader election"); + System.out.println("6. Time 1500: Server 0 recovers and rejoins as follower"); + System.out.println("\nTo run the simulation:"); + System.out.println("1. java -jar target/ds-sim-1.0.1-SNAPSHOT.jar"); + System.out.println("2. File -> Open -> saved-simulations/raft-simple.dat"); + System.out.println("3. Click 'Run' and watch the Raft consensus in action!"); + System.out.println("\nLook for:"); + System.out.println("- REQUEST_VOTE and VOTE_RESPONSE messages during elections"); + System.out.println("- APPEND_ENTRIES messages (heartbeats) from leader"); + System.out.println("- CLIENT_REQUEST messages and their processing"); + + System.exit(0); + } +}
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