Many fixes, some are still only in temporary phase, according to what Arbel told me to do so far.

voting-booth/src/main/java/meerkat/voting/controller/SystemMessages.java

@@ -0,0 +1,84 @@
+package meerkat.voting.controller;
+
+import com.google.protobuf.ByteString;
+import meerkat.protobuf.Voting.*;
+
+/**
+ * Created by hai on 18/05/16.
+ */
+final public class SystemMessages {
+
+    private SystemMessages() {
+        // This is a static class. No instantiation of this is needed.
+    }
+
+    public static UIElement getWaitForCommitMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Please wait while committing to ballot"))
+                .build();
+    }
+
+    public static UIElement getWaitForAuditMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Please wait while auditing your ballot"))
+                .build();
+    }
+
+    public static UIElement getWaitForCastMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Please wait while finalizing your ballot for voting"))
+                .build();
+    }
+
+    public static UIElement getFatalForceRestartMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Fatal error: Internal controller queue received unrecognized command. Force restarting the voting process."))
+                .build();
+    }
+
+    public static UIElement getRestartVotingButton() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Restart voting"))
+                .build();
+    }
+
+    public static UIElement getUnrecognizedFinalizeResponseMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Could not understand response for Cast or Audit. Force restarting."))
+                .build();
+    }
+
+    public static UIElement getUnsuccessfulChannelChoiceMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Choice of channel was unsuccessful. Force restarting."))
+                .build();
+    }
+
+    public static UIElement getOutputDeviceFailureMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Ballot output device failure. Force restarting."))
+                .build();
+    }
+
+    public static UIElement getUnsuccessfulVotingMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Voting was unsuccessful. Force restarting."))
+                .build();
+    }
+
+    public static UIElement getSomethingWrongMessage() {
+        return UIElement.newBuilder()
+                .setType(UIElementDataType.TEXT)
+                .setData(ByteString.copyFromUtf8("Something was terribly wrong. Force restarting."))
+                .build();
+    }
+}

voting-booth/src/main/java/meerkat/voting/controller/VotingBoothController.java

@@ -8,12 +8,13 @@ import meerkat.voting.output.BallotOutputDevice;
 import meerkat.voting.storage.StorageManager;
 
 import java.util.ArrayList;
+import java.util.List;
 
 
 /**
  * An interface for the controller component of the voting booth
  */
-public interface VotingBoothController {
+public interface VotingBoothController extends Runnable{
 
     /**
      * initialize by setting all the different components of the Voting Booth to be recognized by this controller
@@ -31,8 +32,7 @@ public interface VotingBoothController {
      * set the voting questions
      * @param questions
      */
-    public void setBallotChannelChoiceQuestions(BallotQuestion[] questions);
+    public void setBallotChannelChoiceQuestions(List<BallotQuestion> questions);
-    public void setBallotChannelChoiceQuestions(ArrayList<BallotQuestion> questions);
 
     /**
      * Set the channel question-selector (the component which matches the ballot questions to each user)
@@ -44,18 +44,12 @@ public interface VotingBoothController {
      * set the voting race questions
      * @param questions
      */
-    public void setBallotRaceQuestions(BallotQuestion[] questions);
+    public void setBallotRaceQuestions(List<BallotQuestion> questions);
-    public void setBallotRaceQuestions(ArrayList<BallotQuestion> questions);
-
-        /**
-         * a synchronous function. Starts running the controller component, and basically run the whole system for voting
-         */
-    public void run ();
 
     /**
      * an asynchronous call from Admin Console (If there is such one implemented) to shut down the system
      */
-    public void shutDown();
+    public void callShutDown();
 
 
 }

voting-booth/src/main/java/meerkat/voting/controller/VotingBoothImpl.java

@@ -12,20 +12,20 @@ import meerkat.voting.ui.VotingBoothUI;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.LinkedBlockingQueue;
 
 /**
  * Created by hai on 28/03/16.
  */
-public class VotingBoothImpl implements VotingBoothController, Runnable {
+public class VotingBoothImpl implements VotingBoothController {
 
     private BallotOutputDevice outputDevice;
     private VotingBoothEncryptor encryptor;
     private VotingBoothUI ui;
     private StorageManager storageManager;
-    private BallotQuestion[] questionsForChoosingChannel;
+    private List<BallotQuestion> questionsForChoosingChannel;
-    private BallotQuestion[] questions;
+    private List<BallotQuestion> questions;
     private QuestionSelector questionSelector;
 
     private LinkedBlockingQueue<ControllerCommand> queue;
@@ -33,38 +33,18 @@ public class VotingBoothImpl implements VotingBoothController, Runnable {
     private Logger logger;
 
     private ControllerState state;
-    private boolean shutDownHasBeenCalled;
+    private volatile boolean shutDownHasBeenCalled;
 
     protected final int MAX_REQUEST_IDENTIFIER = 100000;
     private static int requestCounter = 0;
 
-    private UIElement waitForCommitMessage;
-    private UIElement waitForAuditMessage;
-    private UIElement waitForCastMessage;
-
-
 
     public VotingBoothImpl () {
         logger = LoggerFactory.getLogger(VotingBoothImpl.class);
         logger.info("A VotingBoothImpl is constructed");
         shutDownHasBeenCalled = false;
         queue = new LinkedBlockingQueue<>();
-
+        state = new ControllerState();
-        waitForCommitMessage = UIElement.newBuilder()
-                .setType(UIElementDataType.TEXT)
-                .setData(ByteString.copyFromUtf8("Please wait while committing to ballot"))
-                .build();
-        waitForAuditMessage = UIElement.newBuilder()
-                .setType(UIElementDataType.TEXT)
-                .setData(ByteString.copyFromUtf8("Please wait while auditing your ballot"))
-                .build();
-        waitForCastMessage = UIElement.newBuilder()
-                .setType(UIElementDataType.TEXT)
-                .setData(ByteString.copyFromUtf8("Please wait while finalizing your ballot for voting"))
-                .build();
-
-        state = new VotingBoothImpl.ControllerState();
-
     }
 
     @Override
@@ -80,42 +60,22 @@ public class VotingBoothImpl implements VotingBoothController, Runnable {
     }
 
     @Override
-    public void setBallotChannelChoiceQuestions(BallotQuestion[] questions) {
+    public void setBallotChannelChoiceQuestions(List<BallotQuestion> questions) {
         logger.info("setting questions");
         this.questionsForChoosingChannel = questions;
     }
 
-    @Override
-    public void setBallotChannelChoiceQuestions(ArrayList<BallotQuestion> questions) {
-        BallotQuestion[] bqArr = new BallotQuestion[questions.size()];
-        for (int i = 0; i < bqArr.length; ++i) {
-            bqArr[i] = questions.get(i);
-        }
-        setBallotChannelChoiceQuestions(bqArr);
-    }
-
     @Override
     public void setChannelQuestionSelector(QuestionSelector selector) {
         this.questionSelector = selector;
     }
 
     @Override
-    public void setBallotRaceQuestions(BallotQuestion[] questions) {
+    public void setBallotRaceQuestions(List<BallotQuestion> questions) {
         logger.info("setting questions");
         this.questions = questions;
     }
 
-    @Override
-    public void setBallotRaceQuestions(ArrayList<BallotQuestion> questions) {
-        // TODO: why does the toArray method not work??
-        //BallotQuestion[] bqArr = (BallotQuestion[])(questions.toArray());
-        BallotQuestion[] bqArr = new BallotQuestion[questions.size()];
-        for (int i = 0; i < bqArr.length; ++i) {
-            bqArr[i] = questions.get(i);
-        }
-        setBallotRaceQuestions(bqArr);
-    }
-
     @Override
     public void run() {
         logger.info("run command has been called");
@@ -124,17 +84,6 @@ public class VotingBoothImpl implements VotingBoothController, Runnable {
 
     }
 
-    @Override
-    public void shutDown() {
-        logger.info("shutDown command has been called");
-        synchronized (this) {
-            shutDownHasBeenCalled = true;
-        }
-
-    }
-
-
-
     private void runVotingFlow () {
         logger.info("entered the voting flow");
 
@@ -151,64 +100,70 @@ public class VotingBoothImpl implements VotingBoothController, Runnable {
         }
     }
 
-    private void doShutDown () {
+    @Override
-        logger.info("running shutDown");
+    public void callShutDown() {
+        logger.info("callShutDown command has been called");
+        shutDownHasBeenCalled = true;
+        queue.clear();
+        queue.add(new ShutDownCommand());
     }
 
     private void handleSingleTask (ControllerCommand task) {
-        if (task instanceof RestartVotingCommand) {
+        if (task.getBallotSerialNumber() != state.currentBallotSerialNumber && !(task instanceof RestartVotingCommand)) {
-            doRestartVoting ();
+            // probably an old command relating to some old ballot serial number. Simply log it and ignore it.
-            return;
-        }
-        if (task.getBallotSerialNumber() != state.currentBallotSerialNumber) {
             String errorMessage = "handleSingleTask: received a task too old. " +
                     task.getBallotSerialNumber() + " " + state.currentBallotSerialNumber;
-            logger.warn (errorMessage);
+            logger.debug(errorMessage);
             return;
         }
 
-        if (task instanceof CastCommand) {
+        if (task instanceof RestartVotingCommand) {
-            doCast();
+            doRestartVoting ();
-            return;
+        }
+        else if (task instanceof CastCommand) {
+            doFinalize(false);
         }
         else if (task instanceof AuditCommand) {
-            doAudit();
+            doFinalize(true);
-            return;
         }
         else if (task instanceof ChannelChoiceCommand) {
             doChooseChannel();
-            return;
         }
         else if (task instanceof ChannelDeterminedCommand) {
             doSetChannelAndAskQuestions ((ChannelDeterminedCommand)task);
-            return;
         }
         else if (task instanceof EncryptAndCommitBallotCommand) {
             doCommit ((EncryptAndCommitBallotCommand)task);
-            return;
+        }
+        else if (task instanceof ReportErrorCommand) {
+            doReportErrorAndForceRestart((ReportErrorCommand)task);
+        }
+        else if (task instanceof ShutDownCommand) {
+            // wasShutDownCalled is now true. Do nothing.
+            // The program will not access the command queue anymore, and will exit normally
+            if (!wasShutDownCalled()) {
+                logger.warn("Received a ShutDownCommand command. At this point shutDownHasBeenCalled flag should have been True, but it's not...");
+                shutDownHasBeenCalled = true;
+            }
         }
         else {
-            String errorMessage = "handleSingleTask: unknown type of ControllerCommand received: " +
+            logger.error("handleSingleTask: unknown type of ControllerCommand received: " + task.getClass().getName());
-                    task.getClass().getName();
+            doReportErrorAndForceRestart(SystemMessages.getSomethingWrongMessage());
-            logger.error(errorMessage);
-            throw new RuntimeException(errorMessage);
         }
     }
 
-    /*
+    private boolean wasShutDownCalled () {
-    Map<string, funcImpl> taskHandlers = new Map<>() {
-CaskTask.getClass().getName() : doCast(),
-ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
-}
-
-
-
-     */
-
-    private synchronized boolean wasShutDownCalled () {
         return shutDownHasBeenCalled;
     }
 
+    private void doShutDown () {
+        logger.info("running callShutDown");
+        state.clearPlaintext();
+        state.clearCiphertext();
+        state.stateIdentifier = VBState.SHUT_DOWN;
+        //TODO: add commands to actually shut down the machine
+    }
+
     private void doRestartVoting () {
         queue.clear();
         state.clearPlaintext();
@@ -216,7 +171,22 @@ ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
         state.stateIdentifier = VBState.NEW_VOTER;
         state.currentBallotSerialNumber += 1;
 
-        ui.startNewVoterSession(new NewVoterCallback(generateRequestIdentifier(), state.currentBallotSerialNumber , this.queue));
+        ui.startNewVoterSession(new NewVoterCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
+    }
+
+    private void doReportErrorAndForceRestart(ReportErrorCommand task) {
+        doReportErrorAndForceRestart(task.getErrorMessage());
+    }
+
+    private void doReportErrorAndForceRestart(UIElement errorMessage) {
+        queue.clear();
+        state.clearPlaintext();
+        state.clearCiphertext();
+        state.stateIdentifier = VBState.FATAL_ERROR_FORCE_NEW_VOTER;
+        state.currentBallotSerialNumber += 1;
+        ui.showErrorMessageWithButtons(errorMessage,
+                new UIElement[]{SystemMessages.getRestartVotingButton()},
+                new ErrorMessageRestartCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
     }
 
     private void doChooseChannel () {
@@ -227,7 +197,7 @@ ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
                     new ChannelChoiceCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
         }
         else {
-            logger.warn("doChooseChannel: current state is " + state.stateIdentifier);
+            logger.debug("doChooseChannel: current state is " + state.stateIdentifier);
             // ignore this request
         }
     }
@@ -236,15 +206,14 @@ ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
         if (state.stateIdentifier == VBState.CHOOSE_CHANNEL) {
             logger.debug("doing set channel and ask questions");
             state.stateIdentifier = VBState.ANSWER_QUESTIONS;
-            BallotAnswer[] channelChoiceAnswers = task.channelChoiceAnswers;
+            List<BallotAnswer> channelChoiceAnswers = task.channelChoiceAnswers;
             state.channelIdentifier = questionSelector.getChannelIdentifier(channelChoiceAnswers);
             state.channelSpecificQuestions = questionSelector.selectQuestionsForVoter(channelChoiceAnswers);
-            state.stateIdentifier = VBState.ANSWER_QUESTIONS;
             ui.askVoterQuestions(state.channelSpecificQuestions,
                     new VotingCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
         }
         else {
-            logger.warn("doSetChannelAndAskQuestions: current state is " + state.stateIdentifier);
+            logger.debug("doSetChannelAndAskQuestions: current state is " + state.stateIdentifier);
             // ignore this request
         }
     }
@@ -254,10 +223,8 @@ ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
         if (state.stateIdentifier == VBState.ANSWER_QUESTIONS) {
             logger.debug("doing commit");
             state.stateIdentifier = VBState.COMMITTING_TO_BALLOT;
-            VotingBoothEncryptor.EncryptionAndSecrets encryptionAndSecrets = encryptor.encrypt(state.plaintextBallot);
+            setBallotData (task);
-            state.encryptedBallot = encryptionAndSecrets.getEncryptedBallot();
+            ui.notifyVoterToWaitForFinish(SystemMessages.getWaitForCommitMessage(),
-            state.secrets = encryptionAndSecrets.getSecrets();
-            ui.notifyVoterToWaitForFinish(waitForCommitMessage,
                     new WaitForFinishCallback(generateRequestIdentifier(),
                             state.currentBallotSerialNumber,
                             this.queue));
@@ -266,38 +233,38 @@ ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
                     new OutputDeviceCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
         }
         else {
-            logger.warn("doCommit: current state is " + state.stateIdentifier);
+            logger.debug("doCommit: current state is " + state.stateIdentifier);
             // ignore this request
         }
     }
 
-
+    private void setBallotData (EncryptAndCommitBallotCommand task) {
-    private void doAudit () {
+        state.plaintextBallot = PlaintextBallot.newBuilder()
-        if (state.stateIdentifier == VBState.CAST_OR_AUDIT) {
+                .setSerialNumber(task.getBallotSerialNumber())
-            logger.debug("doing audit");
+                .addAllAnswers(task.getVotingAnswers())
-            state.stateIdentifier = VBState.FINALIZING;
+                .build();
-            outputDevice.audit(state.secrets,
+        VotingBoothEncryptor.EncryptionAndSecrets encryptionAndSecrets = encryptor.encrypt(state.plaintextBallot);
-                    new OutputDeviceCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
+        state.encryptedBallot = encryptionAndSecrets.getEncryptedBallot();
-            ui.notifyVoterToWaitForFinish(waitForAuditMessage,
+        state.secrets = encryptionAndSecrets.getSecrets();
-                    new WaitForFinishCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
-        }
-        else {
-            logger.warn("doAudit: current state is " + state.stateIdentifier);
-            // ignore this request
-        }
     }
 
-    private void doCast () {
+    private void doFinalize (boolean auditRequested) {
         if (state.stateIdentifier == VBState.CAST_OR_AUDIT) {
-            logger.debug("casting ballot");
+            logger.debug("finalizing");
             state.stateIdentifier = VBState.FINALIZING;
-            outputDevice.castBallot(
+            ui.notifyVoterToWaitForFinish(SystemMessages.getWaitForAuditMessage(),
-                    new OutputDeviceCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
-            ui.notifyVoterToWaitForFinish(waitForCastMessage,
                     new WaitForFinishCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
+            if (auditRequested) {
+                outputDevice.audit(state.secrets,
+                        new OutputDeviceCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
+            }
+            else {
+                outputDevice.castBallot(
+                        new OutputDeviceCallback(generateRequestIdentifier(), state.currentBallotSerialNumber, this.queue));
+            }
         }
         else {
-            logger.warn("doCast: current state is " + state.stateIdentifier);
+            logger.debug("doFinalize: current state is " + state.stateIdentifier);
             // ignore this request
         }
     }
@@ -312,14 +279,16 @@ ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
         ANSWER_QUESTIONS,
         COMMITTING_TO_BALLOT,
         CAST_OR_AUDIT,
-        FINALIZING
+        FINALIZING,
+        FATAL_ERROR_FORCE_NEW_VOTER,
+        SHUT_DOWN
     }
 
 
     private class ControllerState {
-        public VotingBoothImpl.VBState stateIdentifier;
+        public VBState stateIdentifier;
         public int channelIdentifier;
-        public BallotQuestion[] channelSpecificQuestions;
+        public List<BallotQuestion> channelSpecificQuestions;
         public PlaintextBallot plaintextBallot;
         public EncryptedBallot encryptedBallot;
         public BallotSecrets secrets;
@@ -338,12 +307,10 @@ ChannelChoiceCommand.getClass().getName() : doChooseChannel(),
 
 
         public void clearPlaintext () {
-            //TODO: Do we need safe erasure?
             plaintextBallot = null;
         }
 
         public void clearCiphertext () {
-            //TODO: Do we need safe erasure?
             encryptedBallot = null;
             secrets = null;
         }

voting-booth/src/main/java/meerkat/voting/controller/callbacks/CastOrAuditCallback.java

@@ -1,6 +1,6 @@
 package meerkat.voting.controller.callbacks;
 
-
+import meerkat.voting.controller.SystemMessages;
 import meerkat.voting.controller.commands.*;
 import meerkat.voting.controller.commands.ControllerCommand;
 import meerkat.voting.controller.commands.RestartVotingCommand;
@@ -10,7 +10,7 @@ import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.LinkedBlockingQueue;
 
-public class CastOrAuditCallback extends ControllerCallback {
+public class CastOrAuditCallback extends ControllerCallback<FinalizeBallotChoice> {
     protected final static Logger logger = LoggerFactory.getLogger(CastOrAuditCallback.class);
 
     public CastOrAuditCallback(int requestId,
@@ -20,18 +20,18 @@ public class CastOrAuditCallback extends ControllerCallback {
     }
 
     @Override
-    public void onSuccess(Object result) {
+    public void onSuccess(FinalizeBallotChoice result) {
-        assert (result instanceof FinalizeBallotChoice);
-
         if (result == FinalizeBallotChoice.CAST) {
-            controllerQueue.add(new CastCommand(getRequestIdentifier(), getBallotSerialNumber()));
+            enqueueCommand(new CastCommand(getRequestIdentifier(), getBallotSerialNumber()));
         }
         else if (result == FinalizeBallotChoice.AUDIT) {
-            controllerQueue.add(new AuditCommand(getRequestIdentifier(), getBallotSerialNumber()));
+            enqueueCommand(new AuditCommand(getRequestIdentifier(), getBallotSerialNumber()));
         }
         else {
             logger.error("CastOrAuditCallback got an unrecognized response: " + result);
-            controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+            enqueueCommand(new ReportErrorCommand(getRequestIdentifier(),
+                    getBallotSerialNumber(),
+                    SystemMessages.getUnrecognizedFinalizeResponseMessage()));
         }
 
     }
@@ -39,7 +39,9 @@ public class CastOrAuditCallback extends ControllerCallback {
     @Override
     public void onFailure(Throwable t) {
         logger.error("CastOrAuditCallback got a failure: " + t);
-        controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+        enqueueCommand(new ReportErrorCommand(getRequestIdentifier(),
+                getBallotSerialNumber(),
+                SystemMessages.getUnrecognizedFinalizeResponseMessage()));
     }
 }
 

voting-booth/src/main/java/meerkat/voting/controller/callbacks/ChannelChoiceCallback.java

@@ -1,18 +1,18 @@
 package meerkat.voting.controller.callbacks;
 
-import meerkat.protobuf.Voting;
+import meerkat.protobuf.Voting.*;
-import meerkat.voting.controller.commands.ChannelDeterminedCommand;
+import meerkat.voting.controller.SystemMessages;
-import meerkat.voting.controller.commands.ControllerCommand;
+import meerkat.voting.controller.commands.*;
-import meerkat.voting.controller.commands.RestartVotingCommand;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.List;
 import java.util.concurrent.LinkedBlockingQueue;
 
 /**
  * Created by hai on 11/04/16.
  */
-public class ChannelChoiceCallback extends ControllerCallback {
+public class ChannelChoiceCallback extends ControllerCallback<List<BallotAnswer>> {
     protected final static Logger logger = LoggerFactory.getLogger(ChannelChoiceCallback.class);
 
     public ChannelChoiceCallback(int requestId,
@@ -22,22 +22,22 @@ public class ChannelChoiceCallback extends ControllerCallback {
     }
 
     @Override
-    public void onSuccess(Object result) {
+    public void onSuccess(List<BallotAnswer> result) {
-        assert (result instanceof Voting.BallotAnswer[]);
+        if (result.size() != 0) {
-        if (((Voting.BallotAnswer[])result).length != 0) {
             logger.debug("callback for channel choice returned success");
-            controllerQueue.add(
+            enqueueCommand(new ChannelDeterminedCommand(getRequestIdentifier(), getBallotSerialNumber(), result));
-                    new ChannelDeterminedCommand(getRequestIdentifier(), getBallotSerialNumber(), (Voting.BallotAnswer[]) result));
         }
         else {
             logger.debug("ChannelChoiceCallback got a cancellation response: " + result);
-            controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+            enqueueCommand(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
         }
     }
 
     @Override
     public void onFailure(Throwable t) {
         logger.error("channel choice initiated a failure: " + t);
-        controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+        enqueueCommand(new ReportErrorCommand(getRequestIdentifier(),
+                getBallotSerialNumber(),
+                SystemMessages.getUnsuccessfulChannelChoiceMessage()));
     }
 }

voting-booth/src/main/java/meerkat/voting/controller/callbacks/ControllerCallback.java

@@ -1,14 +1,18 @@
 package meerkat.voting.controller.callbacks;
 
+/**
+ * Created by hai on 18/05/16.
+ */
 import com.google.common.util.concurrent.FutureCallback;
 import meerkat.voting.controller.commands.ControllerCommand;
 
 import java.util.concurrent.LinkedBlockingQueue;
 
-public abstract class ControllerCallback implements FutureCallback {
+public abstract class ControllerCallback<T> implements FutureCallback<T> {
+
     private final int requestIdentifier;
     private final long ballotSerialNumber;
-    protected LinkedBlockingQueue<ControllerCommand> controllerQueue;
+    private LinkedBlockingQueue<ControllerCommand> controllerQueue;
 
     protected ControllerCallback (int requestId,
                                   long ballotSerialNumber,
@@ -21,7 +25,13 @@ public abstract class ControllerCallback implements FutureCallback {
     protected int getRequestIdentifier () {
         return requestIdentifier;
     }
+
     protected long getBallotSerialNumber () {
         return ballotSerialNumber;
     }
+
+    protected void enqueueCommand (ControllerCommand command) {
+        controllerQueue.add(command);
+    }
+
 }

voting-booth/src/main/java/meerkat/voting/controller/callbacks/ErrorMessageRestartCallback.java

@@ -0,0 +1,29 @@
+package meerkat.voting.controller.callbacks;
+
+import meerkat.voting.controller.commands.ControllerCommand;
+import meerkat.voting.controller.commands.RestartVotingCommand;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.concurrent.LinkedBlockingQueue;
+
+public class ErrorMessageRestartCallback extends ControllerCallback<Integer> {
+    protected final static Logger logger = LoggerFactory.getLogger(ErrorMessageRestartCallback.class);
+
+    public ErrorMessageRestartCallback(int requestId,
+                                       long ballotSerialNumber,
+                                       LinkedBlockingQueue<ControllerCommand> controllerQueue) {
+        super(requestId, ballotSerialNumber, controllerQueue);
+    }
+
+    @Override
+    public void onSuccess(Integer result) {
+        enqueueCommand(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+    }
+
+    @Override
+    public void onFailure(Throwable t) {
+        logger.error("Error message execution initiated a failure: " + t);
+        enqueueCommand(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+    }
+}

voting-booth/src/main/java/meerkat/voting/controller/callbacks/HaltCallback.java

@@ -1,32 +0,0 @@
-package meerkat.voting.controller.callbacks;
-
-import meerkat.voting.controller.commands.ControllerCommand;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.util.concurrent.LinkedBlockingQueue;
-
-/**
- * Created by hai on 21/04/16.
- */
-public class HaltCallback extends ControllerCallback{
-    protected final static Logger logger = LoggerFactory.getLogger(HaltCallback.class);
-
-    public HaltCallback(int requestId,
-                        long ballotSerialNumber,
-                        LinkedBlockingQueue<ControllerCommand> controllerQueue) {
-        super(requestId, ballotSerialNumber, controllerQueue);
-    }
-
-
-    @Override
-    public void onSuccess(Object result) {
-        throw new UnsupportedOperationException("HaltCallback: onSuccess: There cannot be a successful return for this task. Returned value is " + result);
-    }
-
-    @Override
-    public void onFailure(Throwable t) {
-        logger.error("Halting initiated a failure: " + t);
-    }
-
-}

voting-booth/src/main/java/meerkat/voting/controller/callbacks/NewVoterCallback.java

@@ -8,7 +8,7 @@ import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.LinkedBlockingQueue;
 
-public class NewVoterCallback extends ControllerCallback {
+public class NewVoterCallback extends ControllerCallback<Void> {
     protected final static Logger logger = LoggerFactory.getLogger(NewVoterCallback.class);
 
     public NewVoterCallback(int requestId,
@@ -18,15 +18,14 @@ public class NewVoterCallback extends ControllerCallback {
     }
 
     @Override
-    public void onSuccess(Object v) {
+    public void onSuccess(Void v) {
         logger.debug("callback for new voting returned success");
-        assert v==null;
+        enqueueCommand(new ChannelChoiceCommand(getRequestIdentifier(), getBallotSerialNumber()));
-        controllerQueue.add(new ChannelChoiceCommand(getRequestIdentifier(), getBallotSerialNumber()));
     }
 
     @Override
     public void onFailure(Throwable t) {
         logger.error("New voting session got a failure: " + t);
-        controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+        enqueueCommand(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
     }
 }

voting-booth/src/main/java/meerkat/voting/controller/callbacks/OutputDeviceCallback.java

@@ -1,13 +1,15 @@
 package meerkat.voting.controller.callbacks;
 
+import meerkat.voting.controller.SystemMessages;
 import meerkat.voting.controller.commands.ControllerCommand;
+import meerkat.voting.controller.commands.ReportErrorCommand;
 import meerkat.voting.controller.commands.RestartVotingCommand;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.LinkedBlockingQueue;
 
-public class OutputDeviceCallback extends ControllerCallback {
+public class OutputDeviceCallback extends ControllerCallback<Void> {
     protected final static Logger logger = LoggerFactory.getLogger(OutputDeviceCallback.class);
 
     public OutputDeviceCallback(int requestId,
@@ -17,13 +19,14 @@ public class OutputDeviceCallback extends ControllerCallback {
     }
 
     @Override
-    public void onSuccess(Object v) {
+    public void onSuccess(Void v) {
-        assert v instanceof Void;
     }
 
     @Override
     public void onFailure(Throwable t) {
         logger.error("WaitForFinishCallback got a failure: " + t);
-        controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+        enqueueCommand(new ReportErrorCommand(getRequestIdentifier(),
+                getBallotSerialNumber(),
+                SystemMessages.getOutputDeviceFailureMessage()));
     }
 }

voting-booth/src/main/java/meerkat/voting/controller/callbacks/VotingCallback.java

@@ -1,15 +1,18 @@
 package meerkat.voting.controller.callbacks;
 
-import meerkat.protobuf.Voting;
+import meerkat.protobuf.Voting.*;
+import meerkat.voting.controller.SystemMessages;
 import meerkat.voting.controller.commands.ControllerCommand;
 import meerkat.voting.controller.commands.EncryptAndCommitBallotCommand;
+import meerkat.voting.controller.commands.ReportErrorCommand;
 import meerkat.voting.controller.commands.RestartVotingCommand;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.List;
 import java.util.concurrent.LinkedBlockingQueue;
 
-public class VotingCallback extends ControllerCallback {
+public class VotingCallback extends ControllerCallback<List<BallotAnswer>> {
     protected final static Logger logger = LoggerFactory.getLogger(VotingCallback.class);
 
     public VotingCallback(int requestId,
@@ -19,22 +22,22 @@ public class VotingCallback extends ControllerCallback {
     }
 
     @Override
-    public void onSuccess(Object result) {
+    public void onSuccess(List<BallotAnswer> result) {
-        assert result instanceof Voting.BallotAnswer[];
+        if (result.size() != 0) {
-        if (((Voting.BallotAnswer[])result).length != 0) {
             logger.debug("callback for voting returned success");
-            controllerQueue.add(
+            enqueueCommand(new EncryptAndCommitBallotCommand(getRequestIdentifier(), getBallotSerialNumber(), result));
-                    new EncryptAndCommitBallotCommand(getRequestIdentifier(), getBallotSerialNumber(), (Voting.BallotAnswer[]) result));
         }
         else {
             logger.debug("VotingCallback got a cancellation response: " + result);
-            controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+            enqueueCommand(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
         }
     }
 
     @Override
     public void onFailure(Throwable t) {
         logger.error("voting initiated a failure: " + t);
-        controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+        enqueueCommand(new ReportErrorCommand(getRequestIdentifier(),
+                getBallotSerialNumber(),
+                SystemMessages.getUnsuccessfulVotingMessage()));
     }
 }

voting-booth/src/main/java/meerkat/voting/controller/callbacks/WaitForFinishCallback.java

@@ -1,13 +1,15 @@
 package meerkat.voting.controller.callbacks;
 
+import meerkat.voting.controller.SystemMessages;
 import meerkat.voting.controller.commands.ControllerCommand;
+import meerkat.voting.controller.commands.ReportErrorCommand;
 import meerkat.voting.controller.commands.RestartVotingCommand;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.concurrent.LinkedBlockingQueue;
 
-public class WaitForFinishCallback extends ControllerCallback {
+public class WaitForFinishCallback extends ControllerCallback<Void> {
     protected final static Logger logger = LoggerFactory.getLogger(WaitForFinishCallback.class);
 
     public WaitForFinishCallback(int requestId,
@@ -17,13 +19,14 @@ public class WaitForFinishCallback extends ControllerCallback {
     }
 
     @Override
-    public void onSuccess(Object v) {
+    public void onSuccess(Void v) {
-        assert v instanceof Void;
     }
 
     @Override
     public void onFailure(Throwable t) {
         logger.error("WaitForFinishCallback got a failure: " + t);
-        controllerQueue.add(new RestartVotingCommand(getRequestIdentifier(), getBallotSerialNumber()));
+        enqueueCommand(new ReportErrorCommand(getRequestIdentifier(),
+                getBallotSerialNumber(),
+                SystemMessages.getSomethingWrongMessage()));
     }
 }

voting-booth/src/main/java/meerkat/voting/controller/commands/ChannelDeterminedCommand.java

@@ -1,14 +1,15 @@
 package meerkat.voting.controller.commands;
 
-import meerkat.protobuf.Voting;
+import meerkat.protobuf.Voting.*;
+import java.util.List;
 
 /**
  * Created by hai on 11/04/16.
  */
 public class ChannelDeterminedCommand extends ControllerCommand {
-    public Voting.BallotAnswer[] channelChoiceAnswers;
+    public List<BallotAnswer> channelChoiceAnswers;
 
-    public ChannelDeterminedCommand(int requestIdentifier, long ballotSerialNumber, Voting.BallotAnswer[] answers) {
+    public ChannelDeterminedCommand(int requestIdentifier, long ballotSerialNumber, List<BallotAnswer> answers) {
         super(requestIdentifier, ballotSerialNumber);
         channelChoiceAnswers = answers;
     }

voting-booth/src/main/java/meerkat/voting/controller/commands/EncryptAndCommitBallotCommand.java

@@ -1,12 +1,18 @@
 package meerkat.voting.controller.commands;
 
-import meerkat.protobuf.Voting;
+import meerkat.protobuf.Voting.*;
+
+import java.util.List;
 
 public class EncryptAndCommitBallotCommand extends ControllerCommand {
-    public Voting.BallotAnswer[] votingAnswers;
+    private final List<BallotAnswer> votingAnswers;
 
-    public EncryptAndCommitBallotCommand(int requestIdentifier, long ballotSerialNumber, Voting.BallotAnswer[] answers) {
+    public EncryptAndCommitBallotCommand(int requestIdentifier, long ballotSerialNumber, List<BallotAnswer> answers) {
         super(requestIdentifier, ballotSerialNumber);
         votingAnswers = answers;
     }
+
+    public List<BallotAnswer> getVotingAnswers() {
+        return votingAnswers;
+    }
 }

voting-booth/src/main/java/meerkat/voting/controller/commands/ReportErrorCommand.java

@@ -0,0 +1,16 @@
+package meerkat.voting.controller.commands;
+
+import meerkat.protobuf.Voting.*;
+
+public class ReportErrorCommand extends ControllerCommand {
+    private final UIElement errorMessage;
+
+    public ReportErrorCommand(int requestIdentifier, long ballotSerialNumber, UIElement errorMessage) {
+        super(requestIdentifier, ballotSerialNumber);
+        this.errorMessage = errorMessage;
+    }
+
+    public UIElement getErrorMessage() {
+        return errorMessage;
+    }
+}

voting-booth/src/main/java/meerkat/voting/controller/commands/ShutDownCommand.java

@@ -0,0 +1,10 @@
+package meerkat.voting.controller.commands;
+
+/**
+ * Created by hai on 11/04/16.
+ */
+public class ShutDownCommand extends ControllerCommand {
+    public ShutDownCommand() {
+        super(0, 0);
+    }
+}

voting-booth/src/main/java/meerkat/voting/controller/selector/QuestionSelector.java

@@ -1,20 +1,18 @@
 package meerkat.voting.controller.selector;
 
 import meerkat.protobuf.Voting.*;
+import java.util.List;
 
 /**
  * Created by hai on 02/05/16.
  */
-public abstract class QuestionSelector {
+public interface QuestionSelector {
 
-    protected Object selectionData;
+    public void setAllBallotQuestions (List<BallotQuestion> allBallotQuestions);
-    protected BallotQuestion[] allBallotQuestions;
 
-    public QuestionSelector(Object selectionData, BallotQuestion[] allBallotQuestions) {
+    public void setSelectionData(SelectionData data);
-        this.selectionData = selectionData;
-        this.allBallotQuestions = allBallotQuestions;
-    }
 
-    public abstract int getChannelIdentifier (BallotAnswer[] channelChoiceAnswers);
+    public int getChannelIdentifier (List<BallotAnswer> channelChoiceAnswers);
-    public abstract BallotQuestion[] selectQuestionsForVoter (BallotAnswer[] channelChoiceAnswers);
+
+    public List<BallotQuestion> selectQuestionsForVoter (List<BallotAnswer> channelChoiceAnswers);
 }

voting-booth/src/main/java/meerkat/voting/controller/selector/SelectionData.java

@@ -0,0 +1,7 @@
+package meerkat.voting.controller.selector;
+
+/**
+ * Created by hai on 11/05/16.
+ */
+public class SelectionData {
+}

voting-booth/src/main/java/meerkat/voting/controller/selector/SimpleCategoriesData.java

@@ -1,39 +1,60 @@
 package meerkat.voting.controller.selector;
 
-import java.util.HashMap;
-import java.lang.Math;
-
 /**
- * Created by hai on 02/05/16.
+ * This class is the SelectionData used to initialize a SimpleListCategoriesSelector.
+ * It holds a table of question categories.
+ * Every answer in the channel choice phase dictates a category of questions to include in the ballot.
+ * This class is simply only the data class of these categories.
+ * Specifically the questionSelectionsByAnswer member is this categories table:
+ * questionSelectionsByAnswer[questionNumber][answerNumber] is an array of question indices to include in ballot
+ * whenever the voter answered answerNumber on question questionNumber in the channel choice phase.
+ * Also the sharedDefaults member is a category of question indices to include for EVERY voter,
+ * regardless of his channel choice answers
  */
-public class SimpleCategoriesData {
+public class SimpleCategoriesData extends SelectionData{
 
-    private int[] sharedDefaults;
+    private int[] sharedDefaults;  // a category of questions to include for every voter
-    private HashMap<SingleChosenAnswer, int[]> questionsSelections;
+    // the categories
+    // first index is the question number, the second is the answer number. the value is an array of question indices in this category
+    private int[][][] questionSelectionsByAnswer;
     private int maxQuestionNumber;
 
     public SimpleCategoriesData() {
         sharedDefaults = new int[0];
-        questionsSelections = new HashMap();
+        questionSelectionsByAnswer = new int[0][][];
         maxQuestionNumber = -1;
     }
 
     public void setSharedDefaults(int[] sharedDefaultsIndices) {
-        this.sharedDefaults = sharedDefaultsIndices;
+        this.sharedDefaults = sharedDefaultsIndices.clone();
-        maxQuestionNumber = Math.max(maxQuestionNumber, maxInt(sharedDefaultsIndices));
+        maxQuestionNumber = Math.max(maxQuestionNumber, maxIntInArray(sharedDefaultsIndices));
     }
 
     public int[] getSharedDefaults() {
         return sharedDefaults;
     }
 
-    public void setItem(SingleChosenAnswer key, int[] questionIndices) {
+    public void setItem(int questionNumber, int answerNumber, int[] questionIndices) {
-        questionsSelections.put(key, questionIndices);
+        if (questionNumber >= questionSelectionsByAnswer.length) {
-        maxQuestionNumber = Math.max(maxQuestionNumber, maxInt(questionIndices));
+            int[][][] tmp = new int[questionNumber+1][][];
+            System.arraycopy(questionSelectionsByAnswer, 0, tmp, 0, questionSelectionsByAnswer.length);
+            tmp[questionNumber] = new int[0][];
+            questionSelectionsByAnswer = tmp;
+        }
+
+        if (answerNumber >= questionSelectionsByAnswer[questionNumber].length) {
+            int[][] tmp = new int[answerNumber+1][];
+            System.arraycopy(questionSelectionsByAnswer[questionNumber], 0,
+                    tmp, 0, questionSelectionsByAnswer[questionNumber].length);
+            questionSelectionsByAnswer[questionNumber] = tmp;
+        }
+
+        questionSelectionsByAnswer[questionNumber][answerNumber] = questionIndices.clone();
+        maxQuestionNumber = Math.max(maxQuestionNumber, maxIntInArray(questionIndices));
     }
 
-    public int[] getItem(SingleChosenAnswer key) {
+    public int[] getItem(int questionNumber, int answerNumber) {
-        return questionsSelections.get(key);
+        return questionSelectionsByAnswer[questionNumber][answerNumber];
     }
 
     public int getMaxQuestionNumber() {
@@ -41,7 +62,7 @@ public class SimpleCategoriesData {
     }
 
 
-    private static int maxInt(int[] arr) {
+    private static int maxIntInArray(int[] arr) {
         int m = -1;
         for (int i: arr) {
             m = Math.max(i , m);
@@ -53,8 +74,11 @@ public class SimpleCategoriesData {
         String s = "SimpleCategoriesData:\n";
         s += "shared : " + arrayToString(sharedDefaults) + "\n";
         s += "map : \n";
-        for (SingleChosenAnswer key : questionsSelections.keySet()) {
+        for (int questionNumber = 0; questionNumber < questionSelectionsByAnswer.length; ++questionNumber) {
-            s += key + " : " + arrayToString(questionsSelections.get(key)) + "\n";
+            for (int answerNumber = 0; answerNumber < questionSelectionsByAnswer[questionNumber].length; ++answerNumber) {
+                s += "(" + questionNumber + ", " + answerNumber + ") -> " +
+                        arrayToString(questionSelectionsByAnswer[questionNumber][answerNumber]) + "\n";
+            }
         }
         return s;
     }

voting-booth/src/main/java/meerkat/voting/controller/selector/SimpleListCategoriesSelector.java

@@ -1,75 +1,88 @@
 package meerkat.voting.controller.selector;
 
-import jdk.nashorn.internal.runtime.regexp.joni.exception.ValueException;
+import meerkat.protobuf.Voting.BallotAnswer;
-import meerkat.protobuf.Voting.*;
+import meerkat.protobuf.Voting.BallotQuestion;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.ArrayList;
+import java.util.List;
 
 /**
- * Created by hai on 02/05/16.
+ * A simple implementation of a QuestionSelector.
+ * This implementation simply regards every single answer in the channel choice phase as an identifier of a category
+ * Every category is an array of ballot questions.
+ * Data of categories is initialized and stored by a SimpleCategoriesData object.
+ * After receiving the answers from a channel choice phase, this class simply gathers all the categories
+ * chosen and compiles the list of ballot questions to include in the ballot for this voter (a question
+ * is included if its index appears in any chosen category, or in the default category shared by all voters)
  */
-public class SimpleListCategoriesSelector extends QuestionSelector {
+public class SimpleListCategoriesSelector implements QuestionSelector {
     protected final static Logger logger = LoggerFactory.getLogger(SimpleListCategoriesSelector.class);
+    private BallotQuestion[] allBallotQuestions;
+    private SimpleCategoriesData selectionData;
     private boolean[] isSelected;
 
-    public SimpleListCategoriesSelector(Object selectionData, BallotQuestion[] allBallotQuestions) {
-        super(selectionData, allBallotQuestions);
-        initializeAttributes (allBallotQuestions);
-    }
 
-    public SimpleListCategoriesSelector(Object selectionData, ArrayList<BallotQuestion> allBallotQuestions) {
+    public SimpleListCategoriesSelector() {
-        super(selectionData, null);
+        this.allBallotQuestions = null;
-        BallotQuestion[] questionsArr = new BallotQuestion[allBallotQuestions.size()];
+        this.selectionData = null;
-        for (int i = 0; i < questionsArr.length; ++i) {
-            questionsArr[i] = allBallotQuestions.get(i);
-        }
-        initializeAttributes (questionsArr);
     }
 
-    private void initializeAttributes (BallotQuestion[] allBallotQuestions) {
-        assert selectionData instanceof SimpleCategoriesData;
-        this.allBallotQuestions = allBallotQuestions;
-        SimpleCategoriesData data = (SimpleCategoriesData) selectionData;
-        int maxQuestionNumber = data.getMaxQuestionNumber();
-        int length = allBallotQuestions.length;
-        if (maxQuestionNumber >= length) {
-            String errorMessage = "Selection data refers to question index " + maxQuestionNumber + " while we have only " + length + " questions totally";
-            logger.error(errorMessage);
-            throw new ValueException(errorMessage);
-        }
-        isSelected = new boolean[allBallotQuestions.length];
-    }
-
-
     @Override
-    public int getChannelIdentifier(BallotAnswer[] channelChoiceAnswers) {
+    public void setAllBallotQuestions(List<BallotQuestion> allBallotQuestions) {
+        this.allBallotQuestions = (BallotQuestion[])allBallotQuestions.toArray();
+        isSelected = new boolean[this.allBallotQuestions.length];
+        assertDataValid();
+    }
+
+    @Override
+    public void setSelectionData(SelectionData data) {
+        if (! (data instanceof SimpleCategoriesData)) {
+            String errorMessage = "Initialization of SimpleListCategoriesSelector with wrong object type";
+            logger.error(errorMessage);
+            throw new RuntimeException(errorMessage);
+        }
+        this.selectionData = (SimpleCategoriesData)data;
+        assertDataValid();
+    }
+
+    private void assertDataValid () {
+        if (selectionData != null && allBallotQuestions != null) {
+            int questionsLength = allBallotQuestions.length;
+            int maxQuestionNumber = selectionData.getMaxQuestionNumber();
+            if (maxQuestionNumber >= questionsLength) {
+                String errorMessage = "Selection data refers to question index " + maxQuestionNumber + " while we have only " + questionsLength + " questions totally";
+                logger.error(errorMessage);
+                throw new IndexOutOfBoundsException(errorMessage);
+            }
+        }
+    }
+
+    @Override
+    public int getChannelIdentifier(List<BallotAnswer> channelChoiceAnswers) {
         return 0;
     }
 
     @Override
-    public BallotQuestion[] selectQuestionsForVoter(BallotAnswer[] channelChoiceAnswers) {
+    public List<BallotQuestion> selectQuestionsForVoter(List<BallotAnswer> channelChoiceAnswers) {
-        SimpleCategoriesData data = (SimpleCategoriesData)selectionData;
         java.util.Arrays.fill(isSelected, false);
-        markSelected(data.getSharedDefaults());
+        markSelected(selectionData.getSharedDefaults());
-        markSelectionsOfVoterChannelChoice (channelChoiceAnswers);
+        markSelectionsOfVoterChannelChoice ((BallotAnswer[])channelChoiceAnswers.toArray());
         int[] questionIndices = extractSelectedIndices();
-        BallotQuestion[] selectedQuestions = new BallotQuestion[questionIndices.length];
+        List<BallotQuestion> selectedQuestions = new ArrayList<>();
-        for (int i = 0; i < questionIndices.length; ++i) {
+        for (int questionIndex: questionIndices) {
-            selectedQuestions[i] = allBallotQuestions[questionIndices[i]];
+            selectedQuestions.add(allBallotQuestions[questionIndex]);
         }
         return selectedQuestions;
     }
 
     private void markSelectionsOfVoterChannelChoice(BallotAnswer[] channelChoiceAnswers) {
-        SimpleCategoriesData data = (SimpleCategoriesData)selectionData;
         for (int q = 0; q < channelChoiceAnswers.length; ++q) {
             BallotAnswer ballotAnswer = channelChoiceAnswers[q];
             assertAnswerLengthIsOne(ballotAnswer, q);
-            SingleChosenAnswer key = new SingleChosenAnswer(q, ballotAnswer.getAnswer(0));
+            assertKeyInSelectionData(q, (int)ballotAnswer.getAnswer(0));
-            assertKeyInSelectionData(key);
+            markSelected(selectionData.getItem(q, (int)ballotAnswer.getAnswer(0)));
-            markSelected(data.getItem(key));
         }
     }
 
@@ -81,17 +94,16 @@ public class SimpleListCategoriesSelector extends QuestionSelector {
                 errorMessage += " " + i;
             }
             logger.error(errorMessage);
-            throw new ValueException(errorMessage);
+            throw new IllegalArgumentException(errorMessage);
         }
     }
 
-    private void assertKeyInSelectionData(SingleChosenAnswer key) {
+    private void assertKeyInSelectionData(int questionNumber, int answerNumber) {
-        SimpleCategoriesData data = (SimpleCategoriesData)selectionData;
+        int[] questionListToAdd = selectionData.getItem(questionNumber, answerNumber);
-        int[] questionListToAdd = data.getItem(key);
         if (null == questionListToAdd) {
-            String errorMessage = "SimpleListCategoriesSelector could not resolve answer number " + key.answerNumber + " for question number " + key.questionNumber;
+            String errorMessage = "SimpleListCategoriesSelector could not resolve answer number " + answerNumber + " for question number " + questionNumber;
             logger.error(errorMessage);
-            throw new ValueException(errorMessage);
+            throw new IllegalArgumentException(errorMessage);
         }
     }
 

voting-booth/src/main/java/meerkat/voting/controller/selector/SingleChosenAnswer.java

@@ -1,31 +0,0 @@
-package meerkat.voting.controller.selector;
-
-/**
- * Created by hai on 02/05/16.
- */
-public class SingleChosenAnswer {
-    public int questionNumber;
-    public long answerNumber;
-
-    public SingleChosenAnswer(int questionNumber, long answerNumber) {
-        this.questionNumber = questionNumber;
-        this.answerNumber = answerNumber;
-    }
-
-    public String toString() {
-        return "SingleChosenAnswer(" + questionNumber + ", " + answerNumber + ")";
-    }
-
-    public boolean equals (Object other) {
-        if (!(other instanceof SingleChosenAnswer)) {
-            return false;
-        }
-        SingleChosenAnswer o = (SingleChosenAnswer)other;
-        return (o.questionNumber == this.questionNumber) && (o.answerNumber == this.answerNumber);
-    }
-
-    @Override
-    public int hashCode () {
-        return questionNumber*1000 + (int)answerNumber;
-    }
-}

voting-booth/src/main/java/meerkat/voting/ui/SystemConsoleUI.java

@@ -7,9 +7,7 @@ import meerkat.protobuf.Voting.*;
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
-import java.util.Date;
+import java.util.*;
-import java.util.StringTokenizer;
-import java.util.Timer;
 import java.util.concurrent.LinkedBlockingQueue;
 
 import meerkat.voting.controller.callbacks.*;
@@ -45,54 +43,47 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
         logger.info("entered the voting flow");
         while (true) {
             try {
-                UICommand task = queue.take();
+                UICommand command = queue.take();
-                handleSingleTask (task);
+                handleSingleCommand(command);
             }
             catch (InterruptedException e) {
-                logger.warn ("Interrupted while reading from task queue " + e);
+                logger.warn ("Interrupted while reading from command queue " + e);
             }
         }
     }
 
 
-    private void handleSingleTask (UICommand task) {
+    private void handleSingleCommand(UICommand command) {
-        if (!(task instanceof TickCommand)) {
+        if (!(command instanceof TickCommand)) {
             if (startWaitingTime != null) {
                 stopWaiting();
             }
         }
 
-        if (task instanceof StartSessionUICommand) {
+        if (command instanceof StartSessionUICommand) {
-            doShowWelcomeScreen((StartSessionUICommand)task);
+            doShowWelcomeScreen((StartSessionUICommand)command);
-            return;
         }
-        else if (task instanceof ChannelChoiceUICommand) {
+        else if (command instanceof ChannelChoiceUICommand) {
-            doAskChannelChoiceQuestions((ChannelChoiceUICommand)task);
+            doAskChannelChoiceQuestions((ChannelChoiceUICommand)command);
-            return;
         }
-        else if (task instanceof RaceVotingUICommand) {
+        else if (command instanceof RaceVotingUICommand) {
-            doAskVotingQuestions((RaceVotingUICommand)task);
+            doAskVotingQuestions((RaceVotingUICommand)command);
-            return;
         }
-        else if (task instanceof CastOrAuditUICommand) {
+        else if (command instanceof CastOrAuditUICommand) {
-            doCastOrAudit ((CastOrAuditUICommand)task);
+            doCastOrAudit ((CastOrAuditUICommand)command);
-            return;
         }
-        else if (task instanceof HaltCommand) {
+        else if (command instanceof FatalErrorUICommand) {
-            doHalt((HaltCommand)task);
+            doFatalError((FatalErrorUICommand)command);
-            return;
         }
-        else if (task instanceof WaitForFinishCommand) {
+        else if (command instanceof WaitForFinishUICommand) {
-            doWaitForFinish((WaitForFinishCommand)task);
+            doWaitForFinish((WaitForFinishUICommand)command);
-            return;
         }
-        else if (task instanceof TickCommand) {
+        else if (command instanceof TickCommand) {
             doTick ();
-            return;
         }
         else {
-            String errorMessage = "handleSingleTask: unknown type of UICommand received: " +
+            String errorMessage = "handleSingleCommand: unknown type of UICommand received: " +
-                    task.getClass().getName();
+                    command.getClass().getName();
             logger.error(errorMessage);
             throw new RuntimeException(errorMessage);
         }
@@ -105,13 +96,13 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
         queue.add(new StartSessionUICommand((ControllerCallback)callback));
     }
 
-    private void doShowWelcomeScreen(StartSessionUICommand task) {
+    private void doShowWelcomeScreen(StartSessionUICommand command) {
         logger.debug("UI entered doShowWelcomeScreen");
         System.out.println("Welcome, new voter!");
         waitForEnter(null);
-        ControllerCallback callback = task.getCallback();
+        ControllerCallback callback = command.getCallback();
         assert (callback instanceof NewVoterCallback);
-        ((NewVoterCallback)callback).onSuccess(null);
+        callback.onSuccess(null);
     }
 
     private void stopWaiting () {
@@ -138,45 +129,45 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
     }
 
     @Override
-    public void chooseChannel(BallotQuestion[] questions, FutureCallback<BallotAnswer[]> callback) {
+    public void chooseChannel(List<BallotQuestion> questions, FutureCallback<List<BallotAnswer>> callback) {
         logger.debug("UI interface call to chooseChannel");
-        ChannelChoiceUICommand task = new ChannelChoiceUICommand(questions, (ControllerCallback)callback);
+        ChannelChoiceUICommand command = new ChannelChoiceUICommand(questions, (ControllerCallback)callback);
-        queue.add(task);
+        queue.add(command);
     }
 
-    private void doAskChannelChoiceQuestions (ChannelChoiceUICommand task) {
+    private void doAskChannelChoiceQuestions (ChannelChoiceUICommand command) {
         logger.debug("UI: doAskChannelChoiceQuestions");
         System.out.println("Showing questions for choosing channel:\n");
         try {
-            BallotAnswer[] answers = askVoterForAnswers(task.getQuestions());
+            List<BallotAnswer> answers = askVoterForAnswers(command.getQuestions());
-            task.getCallback().onSuccess(answers);
+            command.getCallback().onSuccess(answers);
         }
         catch (IOException e) {
             String errorMessage = "Channel choice failed due to IOException: " + e;
             logger.error (errorMessage);
             System.err.println(errorMessage);
-            task.getCallback().onFailure(e);
+            command.getCallback().onFailure(e);
         }
     }
 
     @Override
-    public void askVoterQuestions(BallotQuestion[] questions, FutureCallback<BallotAnswer[]> callback) {
+    public void askVoterQuestions(List<BallotQuestion> questions, FutureCallback<List<BallotAnswer>> callback) {
         logger.debug("UI interface call to chooseChannel");
         queue.add(new RaceVotingUICommand(questions, (ControllerCallback)callback));
     }
 
-    private void doAskVotingQuestions (RaceVotingUICommand task) {
+    private void doAskVotingQuestions (RaceVotingUICommand command) {
         logger.debug("UI: doAskVotingQuestions");
         System.out.println("Showing questions for race voting:\n");
         try {
-            BallotAnswer[] answers = askVoterForAnswers(task.getQuestions());
+            List<BallotAnswer> answers = askVoterForAnswers(command.getQuestions());
-            task.getCallback().onSuccess(answers);
+            command.getCallback().onSuccess(answers);
         }
         catch (IOException e) {
             String errorMessage = "Asking voting questions failed due to IOException: " + e;
             logger.error (errorMessage);
             System.err.println(errorMessage);
-            task.getCallback().onFailure(e);
+            command.getCallback().onFailure(e);
         }
     }
 
@@ -186,7 +177,7 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
         queue.add(new CastOrAuditUICommand((ControllerCallback)callback));
     }
 
-    private void doCastOrAudit(CastOrAuditUICommand task) {
+    private void doCastOrAudit(CastOrAuditUICommand command) {
         logger.debug("UI entered doCastOrAudit");
         System.out.println ("Finalizing your vote. Do you wish to (C)ast or (A)udit?");
 
@@ -203,30 +194,30 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
             else {
                 throw new IllegalArgumentException("UI could not understand the answer for cast/audit question '" + s + "'");
             }
-            ControllerCallback callback = task.getCallback();
+            ControllerCallback callback = command.getCallback();
             assert (callback instanceof CastOrAuditCallback);
             ((CastOrAuditCallback)callback).onSuccess(fChoice);
         }
         catch (IllegalArgumentException|IOException e) {
             String errorMessage = "doCastOrAudit: some error with reading input from console. details: " + e;
             logger.error(errorMessage);
-            task.getCallback().onFailure(e);
+            command.getCallback().onFailure(e);
         }
     }
 
 
     @Override
-    public void notifyVoterToWaitForFinish(UIElement message, FutureCallback<Boolean> callback) {
+    public void notifyVoterToWaitForFinish(UIElement message, FutureCallback<Void> callback) {
         logger.debug("UI interface call to notifyVoterToWaitForFinish");
-        queue.add(new WaitForFinishCommand(message, (ControllerCallback)callback));
+        queue.add(new WaitForFinishUICommand(message, (ControllerCallback)callback));
     }
 
-    public void doWaitForFinish (WaitForFinishCommand task) {
+    public void doWaitForFinish (WaitForFinishUICommand command) {
         logger.debug("UI entered doWaitForFinish");
 
         startWaitingTime = new Date();
 
-        UIElement message = task.getMessage();
+        UIElement message = command.getMessage();
         String messageString;
         if (message.getType() != UIElementDataType.TEXT) {
             messageString = "Default message: encountered an error. System halting";
@@ -240,39 +231,57 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
     @Override
     public void showErrorMessageAndHalt(UIElement errorMessage, FutureCallback<Boolean> callback) {
         logger.debug("UI interface call to showErrorMessageAndHalt");
-        queue.add(new HaltCommand(errorMessage, (ControllerCallback)callback));
+        throw new UnsupportedOperationException("Not implemented becuase currently not sure if we ever use it.");
     }
 
-    private void doHalt (HaltCommand task) {
-        logger.debug("UI entered doHalt");
 
-        UIElement errorMessage = task.getErrorMessage();
+    @Override
+    public void showErrorMessageWithButtons(UIElement errorMessage, UIElement[] buttonLabels, FutureCallback<Integer> callback) {
+        logger.debug("UI interface call to showErrorMessageWithButtons");
+        queue.clear();
+        queue.add(new FatalErrorUICommand(errorMessage, buttonLabels, (ControllerCallback)callback));
+    }
+
+    private void doFatalError (FatalErrorUICommand command) {
+        logger.debug("UI entered doFatalError");
+
+        UIElement errorMessage = command.getErrorMessage();
         String errorMessageString;
         if (errorMessage.getType() != UIElementDataType.TEXT) {
             errorMessageString = "Default message: encountered an error. System halting";
         } else {
             errorMessageString = bytesToString(errorMessage.getData());
         }
-        System.out.println(errorMessageString);
 
-        while (true) {
+        UIElement[] buttonLabels = command.getButtonLabels();
-            try {
+        String[] buttonLabelStrings = new String[buttonLabels.length];
-                wait();
+        for (int i = 0; i < buttonLabels.length; ++i) {
-            } catch (InterruptedException e) {
+            if (buttonLabels[i].getType() != UIElementDataType.TEXT) {
-                logger.error("UI halt has been interrupted. Details: " + e);
+                buttonLabelStrings[i] = "<NON_TEXT>";
-                ControllerCallback callback = task.getCallback();
+            } else {
-                assert callback instanceof HaltCallback;
+                buttonLabelStrings[i] = bytesToString(errorMessage.getData());
-                ((HaltCallback) callback).onFailure(e);
             }
         }
+
+        System.out.println(errorMessageString);
+        for (int i = 0; i < buttonLabelStrings.length; ++i) {
+            System.out.println("" + i + " - " + buttonLabelStrings[i]);
+        }
+
+        try {
+            String s = readInputLine();
+            Integer chosenButton = new Integer(s);
+            command.getCallback().onSuccess(chosenButton);
+        }
+        catch (IOException e) {
+            String err = "doFatalError: some error with reading input from console. details: " + e;
+            logger.error(err);
+            command.getCallback().onFailure(e);
+        }
+
     }
 
 
-    @Override
-    public void showErrorMessageWithButtons(UIElement errorMessage, UIElement[] buttonLabels, FutureCallback<Integer> callback) {
-        throw new UnsupportedOperationException();
-    }
-
     private void doTick () {
         if (startWaitingTime != null) {
             System.out.print (".");  // still waiting
@@ -295,9 +304,9 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
     }
 
 
-    private void assertQuestionsAreValid (BallotQuestion[] questions) {
+    private void assertQuestionsAreValid (List<BallotQuestion> questions) {
-        for (int index = 0; index < questions.length; ++index) {
+        for (int index = 0; index < questions.size(); ++index) {
-            BallotQuestion question = questions[index];
+            BallotQuestion question = questions.get(index);
             if (question.getIsMandatory()) {
                 String errorMessage = "askVoterQuestions: question number " + index + " is marked as mandatory";
                 logger.error(errorMessage);
@@ -311,14 +320,14 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
         }
     }
 
-    private BallotAnswer[] askVoterForAnswers(BallotQuestion[] questions) throws IOException {
+    private List<BallotAnswer> askVoterForAnswers(List<BallotQuestion> questions) throws IOException {
 
         assertQuestionsAreValid (questions);
 
-        BallotAnswer answers[] = new BallotAnswer[questions.length];
+        List<BallotAnswer> answers = new ArrayList<>();
         int index = 0;
-        while (index < questions.length) {
+        while (index < questions.size()) {
-            BallotQuestion question = questions[index];
+            BallotQuestion question = questions.get(index);
             System.out.println("Question number " + index);
             showQuestionOnScreen(question);
 
@@ -330,13 +339,14 @@ public class SystemConsoleUI implements VotingBoothUI, Runnable {
             }
             else if (s.equals("back") || s.equals("b")) {
                 --index;
+                answers.remove(index);
             }
             else if (s.equals("skip") || s.equals("s")) {
-                answers[index] = translateStringAnswerToProtoBufMessageAnswer("");
+                answers.add(translateStringAnswerToProtoBufMessageAnswer(""));
                 ++index;
             }
             else {
-                answers[index] = translateStringAnswerToProtoBufMessageAnswer(s);
+                answers.add(translateStringAnswerToProtoBufMessageAnswer(s));
                 ++index;
             }
         }

voting-booth/src/main/java/meerkat/voting/ui/VotingBoothUI.java

@@ -3,6 +3,8 @@ package meerkat.voting.ui;
 import com.google.common.util.concurrent.FutureCallback;
 import meerkat.protobuf.Voting.*;
 
+import java.util.List;
+
 
 /**
  * An interface for the user interface component of the voting booth
@@ -25,14 +27,14 @@ public interface VotingBoothUI {
      * @param questions questions to determine the right voting channel for this voter
      * @param callback that's where we store the answers to decide channel upon for the current voter
      */
-    public void chooseChannel (BallotQuestion[] questions, FutureCallback<BallotAnswer[]> callback);
+    public void chooseChannel (List<BallotQuestion> questions, FutureCallback<List<BallotAnswer>> callback);
 
     /**
      * Presents the set of questions to the voter. Collect all his responses.
      * @param questions all ballot questions to present to the voter
      * @param callback the responses to the questions collected by the UI, to send back to the controller. Responses are null if voter chose to cancel session
      */
-    public void askVoterQuestions (BallotQuestion[] questions, FutureCallback<BallotAnswer[]> callback);
+    public void askVoterQuestions (List<BallotQuestion> questions, FutureCallback<List<BallotAnswer>> callback);
 
     /**
      * Get a response from the voter on how to finalize the ballot.
@@ -51,7 +53,7 @@ public interface VotingBoothUI {
      * @param message a message to show the user on the UI device while waiting
      * @param callback a success return value of the wait (cancelling returns false)
      */
-    public void notifyVoterToWaitForFinish (UIElement message, FutureCallback<Boolean> callback);
+    public void notifyVoterToWaitForFinish (UIElement message, FutureCallback<Void> callback);
 
     /**
      * show a fatal error message in the UI. Halts system. Waits for administrator interrupt or reset

voting-booth/src/main/java/meerkat/voting/ui/uicommands/CastOrAuditUICommand.java

@@ -1,6 +1,6 @@
 package meerkat.voting.ui.uicommands;
 
-import meerkat.voting.controller.callbacks.ControllerCallback;
+import meerkat.voting.controller.callbacks.*;
 
 /**
  * Created by hai on 21/04/16.

voting-booth/src/main/java/meerkat/voting/ui/uicommands/ChannelChoiceUICommand.java

@@ -1,22 +1,24 @@
 package meerkat.voting.ui.uicommands;
 
 import meerkat.protobuf.Voting.*;
-import meerkat.voting.controller.callbacks.ControllerCallback;
+import meerkat.voting.controller.callbacks.*;
+
+import java.util.List;
 
 /**
  * Created by hai on 18/04/16.
  */
 public class ChannelChoiceUICommand extends UICommand {
 
-    private final BallotQuestion[] questions;
+    private final List<BallotQuestion> questions;
 
-    public ChannelChoiceUICommand(BallotQuestion[] questions, ControllerCallback callback)
+    public ChannelChoiceUICommand(List<BallotQuestion> questions, ControllerCallback callback)
     {
         super(callback);
         this.questions = questions;
     }
 
-    public BallotQuestion[] getQuestions () {
+    public List<BallotQuestion> getQuestions () {
         return this.questions;
     }
 }

voting-booth/src/main/java/meerkat/voting/ui/uicommands/FatalErrorUICommand.java

@@ -0,0 +1,28 @@
+package meerkat.voting.ui.uicommands;
+
+import meerkat.protobuf.Voting.UIElement;
+import meerkat.voting.controller.callbacks.*;
+
+/**
+ * Created by hai on 18/04/16.
+ */
+public class FatalErrorUICommand extends UICommand {
+
+    private final UIElement errorMessage;
+    private final UIElement[] buttonLabels;
+
+    public FatalErrorUICommand(UIElement errorMessage, UIElement[] buttonLabels, ControllerCallback callback)
+    {
+        super(callback);
+        this.errorMessage = errorMessage;
+        this.buttonLabels = buttonLabels;
+    }
+
+    public UIElement getErrorMessage() {
+        return this.errorMessage;
+    }
+
+    public UIElement[] getButtonLabels() {
+        return this.getButtonLabels();
+    }
+}

voting-booth/src/main/java/meerkat/voting/ui/uicommands/HaltCommand.java

@@ -1,22 +0,0 @@
-package meerkat.voting.ui.uicommands;
-
-import meerkat.protobuf.Voting.*;
-import meerkat.voting.controller.callbacks.ControllerCallback;
-
-/**
- * Created by hai on 18/04/16.
- */
-public class HaltCommand extends UICommand {
-
-    private final UIElement errorMessage;
-
-    public HaltCommand(UIElement errorMessage, ControllerCallback callback)
-    {
-        super(callback);
-        this.errorMessage = errorMessage;
-    }
-
-    public UIElement getErrorMessage () {
-        return this.errorMessage;
-    }
-}

voting-booth/src/main/java/meerkat/voting/ui/uicommands/RaceVotingUICommand.java

@@ -1,22 +1,24 @@
 package meerkat.voting.ui.uicommands;
 
 import meerkat.protobuf.Voting.*;
-import meerkat.voting.controller.callbacks.ControllerCallback;
+import meerkat.voting.controller.callbacks.*;
+
+import java.util.List;
 
 /**
  * Created by hai on 18/04/16.
  */
 public class RaceVotingUICommand extends UICommand {
 
-    private final BallotQuestion[] questions;
+    private final List<BallotQuestion> questions;
 
-    public RaceVotingUICommand(BallotQuestion[] questions, ControllerCallback callback)
+    public RaceVotingUICommand(List<BallotQuestion> questions, ControllerCallback callback)
     {
         super(callback);
         this.questions = questions;
     }
 
-    public BallotQuestion[] getQuestions () {
+    public List<BallotQuestion> getQuestions () {
         return this.questions;
     }
 }

voting-booth/src/main/java/meerkat/voting/ui/uicommands/StartSessionUICommand.java

@@ -1,6 +1,6 @@
 package meerkat.voting.ui.uicommands;
 
-import meerkat.voting.controller.callbacks.ControllerCallback;
+import meerkat.voting.controller.callbacks.*;
 
 /**
  * Created by hai on 18/04/16.

voting-booth/src/main/java/meerkat/voting/ui/uicommands/TickCommand.java

@@ -1,6 +1,6 @@
 package meerkat.voting.ui.uicommands;
 
-import meerkat.voting.controller.callbacks.ControllerCallback;
+import meerkat.voting.controller.callbacks.*;
 
 /**
  * Created by hai on 18/04/16.

voting-booth/src/main/java/meerkat/voting/ui/uicommands/UICommand.java

@@ -1,6 +1,6 @@
 package meerkat.voting.ui.uicommands;
 
-import meerkat.voting.controller.callbacks.ControllerCallback;
+import meerkat.voting.controller.callbacks.*;
 
 //TODO: make this class generic
 public abstract class UICommand {

voting-booth/src/main/java/meerkat/voting/ui/uicommands/WaitForFinishUICommand.java

@@ -1,17 +1,17 @@
 package meerkat.voting.ui.uicommands;
 
 import meerkat.protobuf.Voting.*;
-import meerkat.voting.controller.callbacks.ControllerCallback;
+import meerkat.voting.controller.callbacks.*;
 
 /**
  * Created by hai on 18/04/16.
  */
 
-public class WaitForFinishCommand extends UICommand {
+public class WaitForFinishUICommand extends UICommand {
 
     private final UIElement message;
 
-    public WaitForFinishCommand(UIElement message, ControllerCallback callback)
+    public WaitForFinishUICommand(UIElement message, ControllerCallback callback)
     {
         super(callback);
         this.message = message;