diff --git a/src/blackmisc/sharedstate/listjournal.cpp b/src/blackmisc/sharedstate/listjournal.cpp
new file mode 100644
index 000000000..3d1855b20
--- /dev/null
+++ b/src/blackmisc/sharedstate/listjournal.cpp
@@ -0,0 +1,40 @@
+/* Copyright (C) 2020
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#include "blackmisc/sharedstate/listjournal.h"
+#include "blackmisc/sharedstate/datalink.h"
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        void CGenericListJournal::initialize(IDataLink *dataLink)
+        {
+            dataLink->publish(m_mutator.data());
+            dataLink->subscribe(m_observer.data());
+            m_observer->setEventSubscription(CVariant::from(CAnyMatch()));
+        }
+
+        CVariant CGenericListJournal::handleRequest(const CVariant &filter)
+        {
+            CVariantList copy = m_value;
+            if (filter.isValid())
+            {
+                copy.removeIf([&filter](const CVariant &v) { return ! filter.matches(v); });
+            }
+            return CVariant::from(copy);
+        }
+
+        void CGenericListJournal::handleEvent(const CVariant &param)
+        {
+            m_value.push_back(param);
+        }
+    }
+}
diff --git a/src/blackmisc/sharedstate/listjournal.h b/src/blackmisc/sharedstate/listjournal.h
new file mode 100644
index 000000000..8f5cb29d4
--- /dev/null
+++ b/src/blackmisc/sharedstate/listjournal.h
@@ -0,0 +1,65 @@
+/* Copyright (C) 2020
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_SHAREDSTATE_LISTJOURNAL_H
+#define BLACKMISC_SHAREDSTATE_LISTJOURNAL_H
+
+#include "blackmisc/sharedstate/activemutator.h"
+#include "blackmisc/sharedstate/passiveobserver.h"
+#include "blackmisc/variantlist.h"
+#include "blackmisc/blackmiscexport.h"
+#include <QObject>
+#include <QMutex>
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        class IDataLink;
+
+        /*!
+         * Non-template base class for CListJournal.
+         */
+        class BLACKMISC_EXPORT CGenericListJournal : public QObject
+        {
+            Q_OBJECT
+
+        public:
+            //! Publish using the given transport mechanism.
+            void initialize(IDataLink *);
+
+        protected:
+            //! Constructor.
+            CGenericListJournal(QObject *parent) : QObject(parent) {}
+
+        private:
+            CVariant handleRequest(const CVariant &filter);
+            void handleEvent(const CVariant &param);
+
+            QSharedPointer<CActiveMutator> m_mutator = CActiveMutator::create(this, &CGenericListJournal::handleRequest);
+            QSharedPointer<CPassiveObserver> m_observer = CPassiveObserver::create(this, &CGenericListJournal::handleEvent);
+            CVariantList m_value;
+        };
+
+        /*!
+         * Base class for an object that shares state with a corresponding CListObserver subclass object.
+         * \tparam T Datatype encapsulating the state to be shared.
+         */
+        template <typename T>
+        class CListJournal : public CGenericListJournal
+        {
+        protected:
+            //! Constructor.
+            CListJournal(QObject *parent) : CGenericListJournal(parent) {}
+        };
+    }
+}
+
+#endif
diff --git a/src/blackmisc/sharedstate/listmutator.cpp b/src/blackmisc/sharedstate/listmutator.cpp
new file mode 100644
index 000000000..8b9b3caf8
--- /dev/null
+++ b/src/blackmisc/sharedstate/listmutator.cpp
@@ -0,0 +1,28 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#include "blackmisc/sharedstate/listmutator.h"
+#include "blackmisc/sharedstate/datalink.h"
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        void CGenericListMutator::initialize(IDataLink *dataLink)
+        {
+            dataLink->publish(m_mutator.data());
+        }
+
+        void CGenericListMutator::addElement(const CVariant &value)
+        {
+            m_mutator->postEvent(value);
+        }
+    }
+}
diff --git a/src/blackmisc/sharedstate/listmutator.h b/src/blackmisc/sharedstate/listmutator.h
new file mode 100644
index 000000000..af20d8506
--- /dev/null
+++ b/src/blackmisc/sharedstate/listmutator.h
@@ -0,0 +1,66 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_SHAREDSTATE_LISTMUTATOR_H
+#define BLACKMISC_SHAREDSTATE_LISTMUTATOR_H
+
+#include "blackmisc/sharedstate/passivemutator.h"
+#include "blackmisc/variantlist.h"
+#include "blackmisc/blackmiscexport.h"
+#include <QObject>
+#include <QMutex>
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        class IDataLink;
+
+        /*!
+         * Non-template base class for CListMutator.
+         */
+        class BLACKMISC_EXPORT CGenericListMutator : public QObject
+        {
+            Q_OBJECT
+
+        public:
+            //! Publish using the given transport mechanism.
+            void initialize(IDataLink *);
+
+        protected:
+            //! Constructor.
+            CGenericListMutator(QObject *parent) : QObject(parent) {}
+
+            //! Add list element as variant.
+            void addElement(const CVariant &value);
+
+        private:
+            QSharedPointer<CPassiveMutator> m_mutator = CPassiveMutator::create(this);
+        };
+
+        /*!
+         * Base class for an object that shares state with a corresponding CListObserver subclass object.
+         * \tparam T Datatype encapsulating the state to be shared.
+         */
+        template <typename T>
+        class CListMutator : public CGenericListMutator
+        {
+        protected:
+            //! Constructor.
+            CListMutator(QObject *parent) : CGenericListMutator(parent) {}
+
+        public:
+            //! Add list element.
+            void addElement(const typename T::value_type &value) { CGenericListMutator::addElement(CVariant::from(value)); }
+        };
+    }
+}
+
+#endif
diff --git a/src/blackmisc/sharedstate/listobserver.cpp b/src/blackmisc/sharedstate/listobserver.cpp
new file mode 100644
index 000000000..46394802e
--- /dev/null
+++ b/src/blackmisc/sharedstate/listobserver.cpp
@@ -0,0 +1,66 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#include "blackmisc/sharedstate/listobserver.h"
+#include "blackmisc/sharedstate/datalink.h"
+#include "blackmisc/variantlist.h"
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        void CGenericListObserver::initialize(IDataLink *dataLink)
+        {
+            dataLink->subscribe(m_observer.data());
+            m_watcher = dataLink->watcher();
+            connect(m_watcher, &CDataLinkConnectionWatcher::connected, this, &CGenericListObserver::reconstruct);
+        }
+
+        void CGenericListObserver::setFilter(const CVariant &filter)
+        {
+            m_observer->setEventSubscription(filter);
+            if (m_watcher && m_watcher->isConnected()) { reconstruct(); }
+        }
+
+        void CGenericListObserver::reconstruct()
+        {
+            m_observer->requestAsync(m_observer->eventSubscription(), [this](const CVariant &list)
+            {
+                QMutexLocker lock(&m_listMutex);
+                m_list = list.to<CVariantList>();
+                lock.unlock();
+                onGenericElementsReplaced(allValues());
+            });
+        }
+
+        CVariantList CGenericListObserver::allValues() const
+        {
+            QMutexLocker lock(&m_listMutex);
+            return m_list;
+        }
+
+        int CGenericListObserver::cleanValues()
+        {
+            QMutexLocker lock(&m_listMutex);
+            return m_list.removeIf([filter = m_observer->eventSubscription()](const CVariant &value)
+            {
+                return !value.matches(filter);
+            });
+        }
+
+        void CGenericListObserver::handleEvent(const CVariant &param)
+        {
+            QMutexLocker lock(&m_listMutex);
+            m_list.push_back(param);
+            lock.unlock();
+            onGenericElementAdded(param);
+        }
+    }
+}
diff --git a/src/blackmisc/sharedstate/listobserver.h b/src/blackmisc/sharedstate/listobserver.h
new file mode 100644
index 000000000..59f42f2fe
--- /dev/null
+++ b/src/blackmisc/sharedstate/listobserver.h
@@ -0,0 +1,99 @@
+/* Copyright (C) 2017
+ * swift Project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
+ * or distributed except according to the terms contained in the LICENSE file.
+ */
+
+//! \file
+
+#ifndef BLACKMISC_SHAREDSTATE_LISTOBSERVER_H
+#define BLACKMISC_SHAREDSTATE_LISTOBSERVER_H
+
+#include "blackmisc/sharedstate/activeobserver.h"
+#include "blackmisc/sharedstate/datalink.h"
+#include "blackmisc/variantlist.h"
+#include "blackmisc/blackmiscexport.h"
+#include <QObject>
+#include <QMutex>
+
+namespace BlackMisc
+{
+    namespace SharedState
+    {
+        /*!
+         * Non-template base class for CListObserver.
+         */
+        class BLACKMISC_EXPORT CGenericListObserver : public QObject
+        {
+            Q_OBJECT
+
+        protected:
+            //! Constructor.
+            CGenericListObserver(QObject *parent) : QObject(parent) {}
+
+            //! Subscribe using the given transport mechanism.
+            virtual void initialize(IDataLink *);
+
+            //! Set list filter as variant.
+            void setFilter(const CVariant &filter);
+
+            //! Get filtered list value as variant list.
+            CVariantList allValues() const;
+
+            //! Remove any old values that no longer match the filter.
+            int cleanValues();
+
+        private:
+            void reconstruct();
+            void handleEvent(const CVariant &param);
+            virtual void onGenericElementAdded(const CVariant &value) = 0;
+            virtual void onGenericElementsReplaced(const CVariantList &values) = 0;
+
+            QSharedPointer<CActiveObserver> m_observer = CActiveObserver::create(this, &CGenericListObserver::handleEvent);
+            CDataLinkConnectionWatcher *m_watcher = nullptr;
+            mutable QMutex m_listMutex;
+            CVariantList m_list;
+        };
+
+        /*!
+         * Base class for an object that shares state with a corresponding CListMutator subclass object.
+         * \tparam T Datatype encapsulating the state to be shared.
+         * \tparam U Datatype describing a filter to apply to the list.
+         */
+        template <typename T, typename U = CAnyMatch>
+        class CListObserver : public CGenericListObserver
+        {
+        protected:
+            //! Constructor.
+            CListObserver(QObject *parent) : CGenericListObserver(parent) {}
+
+        public:
+            //! Subscribe using the given transport mechanism.
+            virtual void initialize(IDataLink *dataLink) override
+            {
+                CGenericListObserver::initialize(dataLink);
+                if (std::is_same<U, CAnyMatch>::value) { setFilter({}); }
+            }
+
+            //! Set filter to choose list elements.
+            void setFilter(const U &filter) { CGenericListObserver::setFilter(CVariant::from(filter)); }
+
+            //! Get list value containing all elements matching the filter.
+            T allValues() const { return CVariant::from(CGenericListObserver::allValues()).template to<T>(); }
+
+            //! Called when an element matching the filter is added to the list.
+            virtual void onElementAdded(const typename T::value_type &value) = 0;
+
+            //! Called when the whole list is updated wholesale.
+            virtual void onElementsReplaced(const T &values) = 0;
+
+        private:
+            virtual void onGenericElementAdded(const CVariant &value) override final { onElementAdded(value.to<typename T::value_type>()); }
+            virtual void onGenericElementsReplaced(const CVariantList &values) override final { onElementsReplaced(values.to<T>()); }
+        };
+    }
+}
+
+#endif