SEBSERV-151 and SEBSERV-189

src/main/java/ch/ethz/seb/sebserver/gbl/model/session/ClientConnection.java

@@ -67,6 +67,7 @@ public final class ClientConnection implements GrantEntity {
     public static final String FILTER_ATTR_SESSION_ID = Domain.CLIENT_CONNECTION.ATTR_EXAM_USER_SESSION_ID;
     public static final String FILTER_ATTR_IP_STRING = Domain.CLIENT_CONNECTION.ATTR_CLIENT_ADDRESS;
     public static final String FILTER_ATTR_INFO = ATTR_INFO;
+    public static final String FILTER_ATTR_TOKEN_LIST = "CONNECTION_TOKENS";
 
     @JsonProperty(Domain.CLIENT_CONNECTION.ATTR_ID)
     public final Long id;
@@ -388,7 +389,7 @@ public final class ClientConnection implements GrantEntity {
     }
 
     public static Predicate<ClientConnection> getStatusPredicate(final ConnectionStatus... status) {
-        final EnumSet<ConnectionStatus> states = EnumSet.allOf(ConnectionStatus.class);
+        final EnumSet<ConnectionStatus> states = EnumSet.noneOf(ConnectionStatus.class);
         if (status != null) {
             Collections.addAll(states, status);
         }

src/main/java/ch/ethz/seb/sebserver/gbl/model/session/ClientInstruction.java

@@ -27,7 +27,8 @@ public final class ClientInstruction {
         SEB_QUIT,
         SEB_PROCTORING,
         SEB_RECONFIGURE_SETTINGS,
-        NOTIFICATION_CONFIRM
+        NOTIFICATION_CONFIRM,
+        SEB_FORCE_LOCK_SCREEN
     }
 
     public enum ProctoringInstructionMethod {
@@ -70,6 +71,11 @@ public final class ClientInstruction {
             public static final String ZOOM_RECEIVE_VIDEO = "zoomReceiveVideo";
             public static final String ZOOM_ALLOW_CHAT = "zoomFeatureFlagChat";
         }
+
+        public interface SEB_FORCE_LOCK_SCREEN {
+            public static final String MESSAGE = "message";
+            public static final String IMAGE_URL = "imageURL";
+        }
     }
 
     @JsonProperty(Domain.CLIENT_INSTRUCTION.ATTR_ID)

src/main/java/ch/ethz/seb/sebserver/gui/content/action/ActionCategory.java

@@ -30,6 +30,9 @@ public enum ActionCategory {
     EXAM_MONITORING_NOTIFICATION_LIST(new LocTextKey(
             "sebserver.monitoring.exam.connection.notificationlist.actions"),
             1),
+    EXAM_MONITORING_2(new LocTextKey(
+            "sebserver.monitoring.exam.connection.selected.actions"), 2),
+    EXAM_MONITORING_3(null, 3),
     CLIENT_EVENT_LIST(new LocTextKey("sebserver.monitoring.exam.connection.list.actions"), 1),
     LOGS_USER_ACTIVITY_LIST(new LocTextKey("sebserver.userlogs.list.actions"), 1),
     LOGS_SEB_CLIENT_LIST(new LocTextKey("sebserver.userlogs.list.actions"), 1),

src/main/java/ch/ethz/seb/sebserver/gui/content/action/ActionDefinition.java

@@ -769,7 +769,7 @@ public enum ActionDefinition {
             new LocTextKey("sebserver.monitoring.exam.connection.action.view"),
             ImageIcon.SHOW,
             PageStateDefinitionImpl.MONITORING_CLIENT_CONNECTION,
-            ActionCategory.CLIENT_EVENT_LIST),
+            ActionCategory.EXAM_MONITORING_3),
     MONITOR_EXAM_CLIENT_CONNECTION_QUIT(
             new LocTextKey("sebserver.monitoring.exam.connection.action.instruction.quit"),
             ImageIcon.SEND_QUIT,
@@ -795,12 +795,18 @@ public enum ActionDefinition {
             new LocTextKey("sebserver.monitoring.exam.connection.action.instruction.quit.selected"),
             ImageIcon.SEND_QUIT,
             PageStateDefinitionImpl.MONITORING_RUNNING_EXAM,
-            ActionCategory.CLIENT_EVENT_LIST),
+            ActionCategory.EXAM_MONITORING_2),
     MONITOR_EXAM_QUIT_ALL(
             new LocTextKey("sebserver.monitoring.exam.connection.action.instruction.quit.all"),
             ImageIcon.SEND_QUIT,
             PageStateDefinitionImpl.MONITORING_RUNNING_EXAM,
             ActionCategory.FORM),
+    MONITOR_EXAM_LOCK_SELECTED(
+            new LocTextKey("sebserver.monitoring.exam.connection.action.instruction.lock.selected"),
+            ImageIcon.LOCK,
+            PageStateDefinitionImpl.MONITORING_RUNNING_EXAM,
+            ActionCategory.EXAM_MONITORING_2),
+
     MONITOR_EXAM_BACK_TO_OVERVIEW(
             new LocTextKey("sebserver.monitoring.exam.action.detail.view"),
             ImageIcon.SHOW,
@@ -811,7 +817,7 @@ public enum ActionDefinition {
             new LocTextKey("sebserver.monitoring.exam.connection.action.disable"),
             ImageIcon.DISABLE,
             PageStateDefinitionImpl.MONITORING_RUNNING_EXAM,
-            ActionCategory.CLIENT_EVENT_LIST),
+            ActionCategory.EXAM_MONITORING_3),
 
     MONITOR_EXAM_HIDE_REQUESTED_CONNECTION(
             new LocTextKey("sebserver.monitoring.exam.connection.action.hide.requested"),

src/main/java/ch/ethz/seb/sebserver/gui/content/exam/ProctoringSettingsPopup.java

@@ -94,6 +94,7 @@ public class ProctoringSettingsPopup {
                     .withAttribute(
                             PageContext.AttributeKeys.FORCE_READ_ONLY,
                             (modifyGrant) ? Constants.FALSE_STRING : Constants.TRUE_STRING);
+
             final ModalInputDialog<FormHandle<?>> dialog =
                     new ModalInputDialog<FormHandle<?>>(
                             action.pageContext().getParent().getShell(),

src/main/java/ch/ethz/seb/sebserver/gui/content/monitoring/MonitoringClientConnection.java

@@ -52,8 +52,8 @@ import ch.ethz.seb.sebserver.gui.service.push.UpdateErrorHandler;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.RestCall;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.RestService;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetExam;
-import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetIndicators;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetExamProctoringSettings;
+import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetIndicators;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.logs.GetExtendedClientEventPage;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.session.ConfirmPendingClientNotification;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.session.GetClientConnectionData;
@@ -365,7 +365,7 @@ public class MonitoringClientConnection implements TemplateComposer {
                 .withConfirm(() -> CONFIRM_QUIT)
                 .withExec(action -> {
                     this.instructionProcessor.propagateSEBQuitInstruction(
-                            exam.id,
+                            exam.getModelId(),
                             connectionToken,
                             pageContext);
                     return action;

src/main/java/ch/ethz/seb/sebserver/gui/content/monitoring/MonitoringRunningExam.java

@@ -55,8 +55,8 @@ import ch.ethz.seb.sebserver.gui.service.page.impl.PageAction;
 import ch.ethz.seb.sebserver.gui.service.push.ServerPushService;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.RestService;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetExam;
-import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetIndicators;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetExamProctoringSettings;
+import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.exam.GetIndicators;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.auth.CurrentUser;
 import ch.ethz.seb.sebserver.gui.service.session.ClientConnectionTable;
 import ch.ethz.seb.sebserver.gui.service.session.FullPageMonitoringGUIUpdate;
@@ -93,6 +93,7 @@ public class MonitoringRunningExam implements TemplateComposer {
     private final AsyncRunner asyncRunner;
     private final InstructionProcessor instructionProcessor;
     private final MonitoringExamSearchPopup monitoringExamSearchPopup;
+    private final SEBSendLockPopup sebSendLockPopup;
     private final MonitoringProctoringService monitoringProctoringService;
     private final boolean distributedSetup;
     private final long pollInterval;
@@ -103,6 +104,7 @@ public class MonitoringRunningExam implements TemplateComposer {
             final AsyncRunner asyncRunner,
             final InstructionProcessor instructionProcessor,
             final MonitoringExamSearchPopup monitoringExamSearchPopup,
+            final SEBSendLockPopup sebSendLockPopup,
             final MonitoringProctoringService monitoringProctoringService,
             final GuiServiceInfo guiServiceInfo,
             @Value("${sebserver.gui.webservice.poll-interval:2000}") final long pollInterval) {
@@ -117,6 +119,7 @@ public class MonitoringRunningExam implements TemplateComposer {
         this.pollInterval = pollInterval;
         this.distributedSetup = guiServiceInfo.isDistributedSetup();
         this.monitoringExamSearchPopup = monitoringExamSearchPopup;
+        this.sebSendLockPopup = sebSendLockPopup;
     }
 
     @Override
@@ -177,11 +180,48 @@ public class MonitoringRunningExam implements TemplateComposer {
                         pageContext,
                         ActionDefinition.MONITOR_EXAM_CLIENT_CONNECTION,
                         ActionDefinition.MONITOR_EXAM_QUIT_SELECTED,
+                        ActionDefinition.MONITOR_EXAM_LOCK_SELECTED,
                         ActionDefinition.MONITOR_EXAM_DISABLE_SELECTED_CONNECTION,
                         ActionDefinition.MONITOR_EXAM_NEW_PROCTOR_ROOM));
 
         actionBuilder
 
+                .newAction(ActionDefinition.MONITORING_EXAM_SEARCH_CONNECTIONS)
+                .withEntityKey(entityKey)
+                .withExec(this::openSearchPopup)
+                .noEventPropagation()
+                .publishIf(isExamSupporter)
+
+                .newAction(ActionDefinition.MONITOR_EXAM_QUIT_ALL)
+                .withEntityKey(entityKey)
+                .withConfirm(() -> CONFIRM_QUIT_ALL)
+                .withExec(action -> this.quitSEBClients(action, clientTable, true))
+                .noEventPropagation()
+                .publishIf(isExamSupporter)
+
+                .newAction(ActionDefinition.MONITOR_EXAM_QUIT_SELECTED)
+                .withEntityKey(entityKey)
+                .withConfirm(() -> CONFIRM_QUIT_SELECTED)
+                .withSelect(
+                        () -> this.selectionForInstruction(clientTable),
+                        action -> this.quitSEBClients(action, clientTable, false),
+                        EMPTY_ACTIVE_SELECTION_TEXT_KEY)
+                .noEventPropagation()
+                .publishIf(isExamSupporter, false)
+
+                .newAction(ActionDefinition.MONITOR_EXAM_LOCK_SELECTED)
+                .withEntityKey(entityKey)
+                .withSelect(
+                        () -> this.selectionForInstruction(clientTable),
+                        action -> this.sebSendLockPopup.show(
+                                action,
+                                statesPredicate -> clientTable.getConnectionTokens(
+                                        statesPredicate,
+                                        true)),
+                        EMPTY_ACTIVE_SELECTION_TEXT_KEY)
+                .noEventPropagation()
+                .publishIf(isExamSupporter, false)
+
                 .newAction(ActionDefinition.MONITOR_EXAM_CLIENT_CONNECTION)
                 .withParentEntityKey(entityKey)
                 .withExec(pageAction -> {
@@ -202,29 +242,6 @@ public class MonitoringRunningExam implements TemplateComposer {
                 })
                 .publishIf(isExamSupporter, false)
 
-                .newAction(ActionDefinition.MONITOR_EXAM_QUIT_ALL)
-                .withEntityKey(entityKey)
-                .withConfirm(() -> CONFIRM_QUIT_ALL)
-                .withExec(action -> this.quitSEBClients(action, clientTable, true))
-                .noEventPropagation()
-                .publishIf(isExamSupporter)
-
-                .newAction(ActionDefinition.MONITORING_EXAM_SEARCH_CONNECTIONS)
-                .withEntityKey(entityKey)
-                .withExec(this::openSearchPopup)
-                .noEventPropagation()
-                .publishIf(isExamSupporter)
-
-                .newAction(ActionDefinition.MONITOR_EXAM_QUIT_SELECTED)
-                .withEntityKey(entityKey)
-                .withConfirm(() -> CONFIRM_QUIT_SELECTED)
-                .withSelect(
-                        () -> this.selectionForQuitInstruction(clientTable),
-                        action -> this.quitSEBClients(action, clientTable, false),
-                        EMPTY_ACTIVE_SELECTION_TEXT_KEY)
-                .noEventPropagation()
-                .publishIf(isExamSupporter, false)
-
                 .newAction(ActionDefinition.MONITOR_EXAM_DISABLE_SELECTED_CONNECTION)
                 .withEntityKey(entityKey)
                 .withConfirm(() -> CONFIRM_DISABLE_SELECTED)
@@ -461,7 +478,7 @@ public class MonitoringRunningExam implements TemplateComposer {
         };
     }
 
-    private Set<EntityKey> selectionForQuitInstruction(final ClientConnectionTable clientTable) {
+    private Set<EntityKey> selectionForInstruction(final ClientConnectionTable clientTable) {
         final Set<String> connectionTokens = clientTable.getConnectionTokens(
                 cc -> cc.status.clientActiveStatus,
                 true);
@@ -478,7 +495,7 @@ public class MonitoringRunningExam implements TemplateComposer {
             final boolean all) {
 
         this.instructionProcessor.propagateSEBQuitInstruction(
-                clientTable.getExam().id,
+                clientTable.getExam().getModelId(),
                 statesPredicate -> clientTable.getConnectionTokens(
                         statesPredicate,
                         !all),
@@ -489,6 +506,23 @@ public class MonitoringRunningExam implements TemplateComposer {
         return action;
     }
 
+//    private PageAction lockSEBClients(
+//            final PageAction action,
+//            final ClientConnectionTable clientTable,
+//            final boolean all) {
+//
+//        this.instructionProcessor.propagateSEBLockInstruction(
+//                clientTable.getExam().getModelId(),
+//                statesPredicate -> clientTable.getConnectionTokens(
+//                        statesPredicate,
+//                        !all),
+//                action.pageContext());
+//
+//        clientTable.removeSelection();
+//        clientTable.forceUpdateAll();
+//        return action;
+//    }
+
     private PageAction disableSEBClients(
             final PageAction action,
             final ClientConnectionTable clientTable,

src/main/java/ch/ethz/seb/sebserver/gui/content/monitoring/SEBSendLockPopup.java

@@ -0,0 +1,213 @@
+/*
+ * Copyright (c) 2022 ETH Zürich, Educational Development and Technology (LET)
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+package ch.ethz.seb.sebserver.gui.content.monitoring;
+
+import java.util.Set;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
+
+import org.apache.tomcat.util.buf.StringUtils;
+import org.eclipse.swt.widgets.Composite;
+import org.springframework.context.annotation.Lazy;
+import org.springframework.stereotype.Component;
+
+import ch.ethz.seb.sebserver.gbl.Constants;
+import ch.ethz.seb.sebserver.gbl.model.Domain;
+import ch.ethz.seb.sebserver.gbl.model.EntityKey;
+import ch.ethz.seb.sebserver.gbl.model.session.ClientConnection;
+import ch.ethz.seb.sebserver.gbl.model.session.ClientConnection.ConnectionStatus;
+import ch.ethz.seb.sebserver.gbl.model.session.ClientInstruction;
+import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
+import ch.ethz.seb.sebserver.gbl.util.Utils;
+import ch.ethz.seb.sebserver.gui.form.FormBuilder;
+import ch.ethz.seb.sebserver.gui.form.FormHandle;
+import ch.ethz.seb.sebserver.gui.service.i18n.LocTextKey;
+import ch.ethz.seb.sebserver.gui.service.page.ModalInputDialogComposer;
+import ch.ethz.seb.sebserver.gui.service.page.PageContext;
+import ch.ethz.seb.sebserver.gui.service.page.PageService;
+import ch.ethz.seb.sebserver.gui.service.page.impl.ModalInputDialog;
+import ch.ethz.seb.sebserver.gui.service.page.impl.PageAction;
+import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.RestService;
+import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.session.GetClientConnectionPage;
+import ch.ethz.seb.sebserver.gui.service.session.InstructionProcessor;
+import ch.ethz.seb.sebserver.gui.table.ColumnDefinition;
+import ch.ethz.seb.sebserver.gui.widget.WidgetFactory.CustomVariant;
+
+@Lazy
+@Component
+@GuiProfile
+public class SEBSendLockPopup {
+
+    private static final LocTextKey TITLE_TEXT_KEY =
+            new LocTextKey("sebserver.monitoring.lock.title");
+    private static final LocTextKey FORM_INFO_TITLE =
+            new LocTextKey("sebserver.monitoring.lock.form.info.title");
+    private static final LocTextKey FORM_INFO =
+            new LocTextKey("sebserver.monitoring.lock.form.info");
+    private static final LocTextKey FORM_MESSAGE =
+            new LocTextKey("sebserver.monitoring.lock.form.message");
+
+    private static final LocTextKey TABLE_TITLE =
+            new LocTextKey("sebserver.monitoring.lock.list.title");
+    private static final LocTextKey TABLE_COLUMN_NAME =
+            new LocTextKey("sebserver.monitoring.lock.list.name");
+    private static final LocTextKey TABLE_COLUMN_INFO =
+            new LocTextKey("sebserver.monitoring.lock.list.info");
+
+    private final PageService pageService;
+    private final InstructionProcessor instructionProcessor;
+
+    protected SEBSendLockPopup(
+            final PageService pageService,
+            final InstructionProcessor instructionProcessor) {
+
+        this.pageService = pageService;
+        this.instructionProcessor = instructionProcessor;
+    }
+
+    public PageAction show(
+            final PageAction action,
+            final Function<Predicate<ClientConnection>, Set<String>> selectionFunction) {
+
+        final PageContext pageContext = action.pageContext();
+        final Set<String> selection = selectionFunction.apply(ClientConnection.getStatusPredicate(
+                ConnectionStatus.CONNECTION_REQUESTED,
+                ConnectionStatus.ACTIVE));
+
+        if (selection == null || selection.isEmpty()) {
+            action
+                    .pageContext()
+                    .publishInfo(new LocTextKey("sebserver.monitoring.lock.noselection"));
+            return action;
+        }
+
+        final String connectionTokens = StringUtils.join(selection, Constants.LIST_SEPARATOR_CHAR);
+        final boolean showList = selection.size() > 1;
+        final PopupComposer popupComposer = new PopupComposer(
+                this.pageService,
+                pageContext,
+                connectionTokens,
+                showList);
+
+        final ModalInputDialog<FormHandle<?>> dialog =
+                new ModalInputDialog<FormHandle<?>>(
+                        action.pageContext().getParent().getShell(),
+                        this.pageService.getWidgetFactory())
+                                .setDialogWidth(800)
+                                .setDialogHeight(showList ? 500 : 200);
+
+        final Predicate<FormHandle<?>> doLock = formHandle -> propagateLockInstruction(
+                connectionTokens,
+                pageContext,
+                formHandle);
+
+        dialog.open(
+                TITLE_TEXT_KEY,
+                doLock,
+                Utils.EMPTY_EXECUTION,
+                popupComposer);
+
+        return action;
+    }
+
+    private final class PopupComposer implements ModalInputDialogComposer<FormHandle<?>> {
+
+        private final PageService pageService;
+        private final PageContext pageContext;
+        private final String connectionTokens;
+        private final boolean showList;
+
+        protected PopupComposer(
+                final PageService pageService,
+                final PageContext pageContext,
+                final String connectionTokens,
+                final boolean showList) {
+
+            this.pageService = pageService;
+            this.pageContext = pageContext;
+            this.connectionTokens = connectionTokens;
+            this.showList = showList;
+        }
+
+        @Override
+        public Supplier<FormHandle<?>> compose(final Composite parent) {
+            final EntityKey examKey = this.pageContext.getEntityKey();
+            final RestService restService = this.pageService.getRestService();
+
+            final PageContext formContext = this.pageContext.copyOf(parent);
+            final FormHandle<?> form = this.pageService.formBuilder(formContext)
+                    .addField(FormBuilder.text(
+                            "Info",
+                            FORM_INFO_TITLE,
+                            this.pageService.getI18nSupport().getText(FORM_INFO))
+                            .asArea(50)
+                            .asHTML()
+                            .readonly(true))
+                    .addField(FormBuilder.text(
+                            ClientInstruction.SEB_INSTRUCTION_ATTRIBUTES.SEB_FORCE_LOCK_SCREEN.MESSAGE,
+                            FORM_MESSAGE)
+                            .asArea(50)
+                            .asHTML())
+                    .build();
+
+            if (this.showList) {
+                this.pageService
+                        .getWidgetFactory()
+                        .labelLocalized(parent, CustomVariant.TEXT_H3, TABLE_TITLE);
+
+                // table of selected SEB connections
+                this.pageService
+                        .entityTableBuilder(restService.getRestCall(GetClientConnectionPage.class))
+                        .withStaticFilter(
+                                ClientConnection.FILTER_ATTR_TOKEN_LIST,
+                                this.connectionTokens)
+                        .withStaticFilter(
+                                ClientConnection.FILTER_ATTR_EXAM_ID,
+                                examKey.modelId)
+                        .withPaging(10)
+
+                        .withColumn(new ColumnDefinition<>(
+                                Domain.CLIENT_CONNECTION.ATTR_EXAM_USER_SESSION_ID,
+                                TABLE_COLUMN_NAME,
+                                ClientConnection::getUserSessionId))
+
+                        .withColumn(new ColumnDefinition<>(
+                                ClientConnection.ATTR_INFO,
+                                TABLE_COLUMN_INFO,
+                                ClientConnection::getInfo))
+
+                        .compose(formContext);
+            }
+
+            return () -> form;
+        }
+    }
+
+    private boolean propagateLockInstruction(
+            final String connectionTokens,
+            final PageContext pageContext,
+            final FormHandle<?> formHandle) {
+
+        final EntityKey examKey = pageContext.getEntityKey();
+        final String lockMessage = formHandle
+                .getForm()
+                .getFieldValue(ClientInstruction.SEB_INSTRUCTION_ATTRIBUTES.SEB_FORCE_LOCK_SCREEN.MESSAGE);
+
+        this.instructionProcessor.propagateSEBLockInstruction(
+                examKey.modelId,
+                lockMessage,
+                null,
+                connectionTokens,
+                pageContext);
+
+        return true;
+    }
+
+}

src/main/java/ch/ethz/seb/sebserver/gui/service/session/InstructionProcessor.java

@@ -9,6 +9,8 @@
 package ch.ethz.seb.sebserver.gui.service.session;
 
 import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -55,7 +57,7 @@ public class InstructionProcessor {
     }
 
     public void propagateSEBQuitInstruction(
-            final Long examId,
+            final String examId,
             final String connectionToken,
             final PageContext pageContext) {
 
@@ -67,40 +69,89 @@ public class InstructionProcessor {
     }
 
     public void propagateSEBQuitInstruction(
-            final Long examId,
+            final String examId,
             final Function<Predicate<ClientConnection>, Set<String>> selectionFunction,
             final PageContext pageContext) {
 
-        final Set<String> connectionTokens = selectionFunction
+        try {
-                .apply(ClientConnection.getStatusPredicate(
+            final Set<String> connectionTokens = selectionFunction
-                        ConnectionStatus.CONNECTION_REQUESTED,
+                    .apply(ClientConnection.getStatusPredicate(
-                        ConnectionStatus.ACTIVE));
+                            ConnectionStatus.CONNECTION_REQUESTED,
+                            ConnectionStatus.ACTIVE));
 
-        if (connectionTokens.isEmpty()) {
+            if (connectionTokens.isEmpty()) {
-            log.warn("Empty selection");
+                return;
-            return;
+            }
+
+            if (log.isDebugEnabled()) {
+                log.debug("Propagate SEB quit instruction for exam: {} and connections: {}",
+                        examId,
+                        connectionTokens);
+            }
+
+            final ClientInstruction clientInstruction = new ClientInstruction(
+                    null,
+                    Long.valueOf(examId),
+                    InstructionType.SEB_QUIT,
+                    StringUtils.join(connectionTokens, Constants.LIST_SEPARATOR),
+                    null);
+
+            processInstruction(() -> this.restService.getBuilder(PropagateInstruction.class)
+                    .withURIVariable(API.PARAM_PARENT_MODEL_ID, String.valueOf(examId))
+                    .withBody(clientInstruction)
+                    .call()
+                    .getOrThrow(),
+                    pageContext);
+
+        } catch (final Exception e) {
+            pageContext.notifyUnexpectedError(e);
         }
+    }
 
-        if (log.isDebugEnabled()) {
+    public void propagateSEBLockInstruction(
-            log.debug("Propagate SEB quit instruction for exam: {} and connections: {}",
+            final String examId,
-                    examId,
+            final String message,
-                    connectionTokens);
+            final String imageURL,
+            final String connectionTokens,
+            final PageContext pageContext) {
+
+        try {
+
+            if (connectionTokens.isEmpty()) {
+                return;
+            }
+
+            if (log.isDebugEnabled()) {
+                log.debug("Propagate SEB lock instruction for exam: {} and connections: {}",
+                        examId,
+                        connectionTokens);
+            }
+
+            final Map<String, String> attributes = new HashMap<>();
+            if (StringUtils.isNotBlank(message)) {
+                attributes.put(ClientInstruction.SEB_INSTRUCTION_ATTRIBUTES.SEB_FORCE_LOCK_SCREEN.MESSAGE, message);
+            }
+            if (StringUtils.isNotBlank(imageURL)) {
+                attributes.put(ClientInstruction.SEB_INSTRUCTION_ATTRIBUTES.SEB_FORCE_LOCK_SCREEN.IMAGE_URL, imageURL);
+            }
+
+            final ClientInstruction clientInstruction = new ClientInstruction(
+                    null,
+                    Long.valueOf(examId),
+                    InstructionType.SEB_FORCE_LOCK_SCREEN,
+                    connectionTokens,
+                    attributes);
+
+            processInstruction(() -> this.restService.getBuilder(PropagateInstruction.class)
+                    .withURIVariable(API.PARAM_PARENT_MODEL_ID, examId)
+                    .withBody(clientInstruction)
+                    .call()
+                    .getOrThrow(),
+                    pageContext);
+
+        } catch (final Exception e) {
+            pageContext.notifyUnexpectedError(e);
         }
-
-        final ClientInstruction clientInstruction = new ClientInstruction(
-                null,
-                examId,
-                InstructionType.SEB_QUIT,
-                StringUtils.join(connectionTokens, Constants.LIST_SEPARATOR),
-                null);
-
-        processInstruction(() -> this.restService.getBuilder(PropagateInstruction.class)
-                .withURIVariable(API.PARAM_PARENT_MODEL_ID, String.valueOf(examId))
-                .withBody(clientInstruction)
-                .call()
-                .getOrThrow(),
-                pageContext);
-
     }
 
     public void disableConnection(
@@ -113,6 +164,7 @@ public class InstructionProcessor {
                         ConnectionStatus.CONNECTION_REQUESTED,
                         ConnectionStatus.UNDEFINED,
                         ConnectionStatus.CLOSED,
+                        ConnectionStatus.ACTIVE,
                         ConnectionStatus.AUTHENTICATED));
 
         if (connectionTokens.isEmpty()) {

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/dao/FilterMap.java

@@ -9,6 +9,7 @@
 package ch.ethz.seb.sebserver.webservice.servicelayer.dao;
 
 import java.util.Arrays;
+import java.util.List;
 import java.util.Set;
 
 import org.apache.commons.lang3.StringUtils;
@@ -206,6 +207,15 @@ public class FilterMap extends POSTMapper {
         return Utils.toSQLWildcard(this.params.getFirst(name));
     }
 
+    public List<String> getClientConnectionTokenList() {
+        final String tokenList = getString(ClientConnection.FILTER_ATTR_TOKEN_LIST);
+        if (StringUtils.isBlank(tokenList)) {
+            return null;
+        }
+
+        return Utils.asImmutableList(StringUtils.split(tokenList, Constants.LIST_SEPARATOR));
+    }
+
     public Long getClientConnectionExamId() {
         return getLong(ClientConnection.FILTER_ATTR_EXAM_ID);
     }

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/dao/impl/ClientConnectionDAOImpl.java

@@ -125,6 +125,9 @@ public class ClientConnectionDAOImpl implements ClientConnectionDAO {
                                             ClientConnectionRecordDynamicSqlSupport.institutionId,
                                             isEqualToWhenPresent(filterMap.getInstitutionId()));
             return whereClause
+                    .and(
+                            ClientConnectionRecordDynamicSqlSupport.connectionToken,
+                            isInWhenPresent(filterMap.getClientConnectionTokenList()))
                     .and(
                             ClientConnectionRecordDynamicSqlSupport.examId,
                             isEqualToWhenPresent(filterMap.getClientConnectionExamId()))

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/session/impl/SEBClientConnectionServiceImpl.java

@@ -63,6 +63,7 @@ public class SEBClientConnectionServiceImpl implements SEBClientConnectionServic
                     ConnectionStatus.UNDEFINED,
                     ConnectionStatus.CONNECTION_REQUESTED,
                     ConnectionStatus.AUTHENTICATED,
+                    ConnectionStatus.ACTIVE,
                     ConnectionStatus.CLOSED);
 
     private final ExamSessionService examSessionService;

src/main/resources/messages.properties

@@ -1873,6 +1873,8 @@ sebserver.monitoring.exam.connection.action.instruction.quit.all=Quit All SEB Cl
 sebserver.monitoring.exam.connection.action.instruction.quit.confirm=Are you sure to quit this SEB client connection?
 sebserver.monitoring.exam.connection.action.instruction.quit.selected.confirm=Are you sure to quit all selected, active SEB client connections?
 sebserver.monitoring.exam.connection.action.instruction.quit.all.confirm=Are you sure to quit all active SEB client connections?
+sebserver.monitoring.exam.connection.action.instruction.lock.selected=Lock Selected SEB Clients
+sebserver.monitoring.exam.connection.action.instruction.lock.confirm=Are you sure to lock this SEB client connection?
 sebserver.monitoring.exam.connection.action.instruction.disable.selected.confirm=Are you sure to disable all selected SEB client connections?
 sebserver.monitoring.exam.connection.action.instruction.disable.all.confirm=Are you sure to disable all active SEB client connections?
 sebserver.monitoring.exam.connection.action.disable=Mark As Canceled
@@ -1891,6 +1893,7 @@ sebserver.monitoring.exam.connection.action.proctoring.examroom=Exam Room Procto
 sebserver.monitoring.exam.connection.action.openTownhall.confirm=You are about to open the town-hall room and force all SEB clients to join the town-hall room.<br/>Are you sure to open the town-hall?
 sebserver.monitoring.exam.connection.action.closeTownhall.confirm=You are about to close the town-hall room and force all SEB clients to join it's proctoring room.<br/>Are you sure to close the town-hall?
 sebserver.monitoring.exam.connection.action.singleroom.confirm=You are about to open the single/one to one room for this participant.<br/>Are you sure you want to open the single room?
+sebserver.monitoring.exam.connection.selected.actions=&nbsp;
 
 sebserver.monitoring.exam.connection.notificationlist.actions=
 sebserver.monitoring.exam.connection.action.confirm.notification=Confirm Notification
@@ -1936,6 +1939,16 @@ sebserver.monitoring.exam.connection.status.CLOSED=Closed
 sebserver.monitoring.exam.connection.status.ABORTED=Aborted
 sebserver.monitoring.exam.connection.status.DISABLED=Canceled
 
+sebserver.monitoring.lock.title=Lock SEB Clients
+sebserver.monitoring.lock.form.info.title=Info
+sebserver.monitoring.lock.form.info=Please check all selected SEB connection<br/>before sending lock by click on "OK"
+sebserver.monitoring.lock.form.message=Lock Message
+sebserver.monitoring.lock.form.message.tooltip=A message that will be displayed by the SEB with the lock screen to the user
+sebserver.monitoring.lock.list.title=Selected SEB Client Connections
+sebserver.monitoring.lock.list.name=SEB User Session Identifier
+sebserver.monitoring.lock.list.info=SEB Connection Info
+sebserver.monitoring.lock.noselection=Please select at least one active SEB client connection.
+
 ################################
 # Finished Exams
 ################################