'Bounded Retransmission Protocol' Blob

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diff --git a/assignments/assignment2/Bounded Retransmission Protocol Tester/Source/basiclearner/ExampleSUL.java b/assignments/assignment2/Bounded Retransmission Protocol Tester/Source/basiclearner/ExampleSUL.java
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+++ b/assignments/assignment2/Bounded Retransmission Protocol Tester/Source/basiclearner/ExampleSUL.java
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+package basiclearner;
+
+import de.learnlib.api.SUL;
+import de.learnlib.api.SULException;
+
+/**
+ * Example of a three-state system, hard-coded.
+ * 
+ * @author Ramon Janssen
+ */
+public class ExampleSUL implements SUL<String, String> {
+	private enum State{s0,s1,s2};
+	private State currentState;
+	private static boolean VERBOSE = false;
+	
+	@Override
+	public void pre() {
+		// add any code here that should be run at the beginning of every 'session',
+		// i.e. put the system in its initial state
+		if (VERBOSE) {
+			System.out.println("Starting SUL");
+		}
+		currentState = State.s0;
+	}
+	
+	@Override
+	public void post() {
+		// add any code here that should be run at the end of every 'session'
+		if (VERBOSE) {
+			System.out.println("Shutting down SUL");
+		}
+	}
+
+	@Override
+	public String step(String input) throws SULException {
+		State previousState = this.currentState;
+		String output = makeTransition(input);
+		State nextState = this.currentState; 
+		if (VERBOSE) {
+			System.out.println(previousState + " --" + input + "/" + output + "-> " + nextState);
+		}
+		return output;
+	}
+	
+	/**
+	 * The behaviour of the SUL. It takes one input, and returns an output. It now
+	 * contains a hardcoded state-machine (so the result is easy to check). To learn
+	 * an external program/system, connect this method to the SUL (e.g. via sockets
+	 * or stdin/stdout) and make it perform an actual input, and retrieve an actual
+	 * output.
+	 * @param input
+	 * @return
+	 */
+	public String makeTransition(String input) {
+		switch (currentState) {
+		case s0:
+			switch(input) {
+			case "a":
+				currentState = State.s1;
+				return "x";
+			case "b":
+				currentState = State.s2;
+				return "y";
+			case "c":
+				return "z";
+			}
+		case s1:
+			switch(input) {
+			case "a":
+				return "z";
+			case "b":
+				currentState = State.s2;
+				return "y";
+			case "c":
+				return "z";
+			}
+		case s2:
+			switch(input) {
+			case "a":
+				return "z";
+			case "b":
+				currentState = State.s0;
+				return "y";
+			case "c":
+				return "z";
+			}
+		}
+		throw new SULException(new IllegalArgumentException("Argument '" + input + "' was not handled"));
+	}
+}