diff --git a/README.md b/README.md
index 47d3b7c..5b13697 100644
--- a/README.md
+++ b/README.md
@@ -199,3 +199,47 @@ Methods:
 * apply()
 
 
+# Example usage
+
+```
+class dbms_server : public trrep::server_context
+{
+  public:
+  // Implementation
+    void start()
+    {
+      // Initialize server components, start accepting client connections
+    }
+};
+
+class dbms_client : public trrep::client_context
+{
+  // Implementation
+};
+
+int main()
+{
+  dbms_server server(name, id);
+
+  if (server.sst_before_init())
+  {
+    server.start();
+    server.wait_until_state(trrep::server_context::s_joined);
+
+  }
+  // Initialize dbms code here
+  if (server.sst_before_init() == false)
+  {
+    server.start();
+    server.wait_until_state(trrep::server_context::s_joined);
+  }
+
+  // Start accepting client connections
+  server.wait_until_state(trrep::server_context::s_synced);
+
+  // Clients can read and write here
+
+
+}
+
+```
\ No newline at end of file
diff --git a/doc/Doxyfile b/doc/Doxyfile
index 4d3808f..8243a4a 100644
--- a/doc/Doxyfile
+++ b/doc/Doxyfile
@@ -424,7 +424,7 @@ EXTRACT_ALL            = NO
 # be included in the documentation.
 # The default value is: NO.
 
-EXTRACT_PRIVATE        = NO
+EXTRACT_PRIVATE        = YES
 
 # If the EXTRACT_PACKAGE tag is set to YES, all members with package or internal
 # scope will be included in the documentation.
diff --git a/src/client_context.cpp b/src/client_context.cpp
index 3c445ca..5581249 100644
--- a/src/client_context.cpp
+++ b/src/client_context.cpp
@@ -74,14 +74,3 @@ int trrep::client_context::after_statement()
 #endif // 0
     return 0;
 }
-
-// TODO: This should be pure virtual method, implemented by
-// DBMS integration or mock classes only.
-int trrep::client_context::replay(
-    trrep::unique_lock<trrep::mutex>& lock,
-    trrep::transaction_context& tc)
-{
-    tc.state(lock, trrep::transaction_context::s_replaying);
-    tc.state(lock, trrep::transaction_context::s_committed);
-    return 0;
-}
diff --git a/src/client_context.hpp b/src/client_context.hpp
index 9a7124d..821ab57 100644
--- a/src/client_context.hpp
+++ b/src/client_context.hpp
@@ -113,67 +113,11 @@ namespace trrep
             s_quitting
         };
 
-
+        /*!
+         * Destructor.
+         */
         virtual ~client_context() { }
 
-        /*!
-         * Get reference to the client mutex.
-         *
-         * \return Reference to the client mutex.
-         */
-        trrep::mutex& mutex() { return mutex_; }
-
-        /*!
-         * Get server context associated the the client session.
-         *
-         * \return Reference to server context.
-         */
-        trrep::server_context& server_context() const
-        { return server_context_; }
-
-        /*!
-         * Get reference to the Provider which is associated
-         * with the client context.
-         *
-         * \return Reference to the provider.
-         * \throw trrep::runtime_error if no providers are associated
-         *        with the client context.
-         */
-        trrep::provider& provider() const;
-
-        /*!
-         * Get Client identifier.
-         *
-         * \return Client Identifier
-         */
-        client_id id() const { return id_; }
-
-        /*!
-         * Get Client mode.
-         *
-         * \todo Enforce mutex protection if called from other threads.
-         *
-         * \return Client mode.
-         */
-        enum mode mode() const { return mode_; }
-
-        /*!
-         * Get Client state.
-         *
-         * \todo Enforce mutex protection if called from other threads.
-         *
-         * \return Client state
-         */
-        enum state state() const { return state_; }
-
-        /*!
-         * Virtual method to return true if the client operates
-         * in two phase commit mode.
-         *
-         * \return True if two phase commit is required, false otherwise.
-         */
-        virtual bool do_2pc() const = 0;
-
         /*!
          * Virtual method which should be called before the client
          * starts processing the command received from the application.
@@ -229,55 +173,50 @@ namespace trrep
         virtual int after_statement();
 
         /*!
-         * Append SR fragment to the transaction.
+         * Get reference to the client mutex.
+         *
+         * \return Reference to the client mutex.
          */
-        virtual int append_fragment(trrep::transaction_context&,
-                                    uint32_t, const trrep::data&)
-        { return 0; }
+        trrep::mutex& mutex() { return mutex_; }
 
         /*!
-         * Commit the transaction.
+         * Get server context associated the the client session.
+         *
+         * \return Reference to server context.
          */
-        virtual int commit(trrep::transaction_context&) = 0;
+        trrep::server_context& server_context() const
+        { return server_context_; }
 
         /*!
-         * Rollback the transaction.
+         * Get reference to the Provider which is associated
+         * with the client context.
+         *
+         * \return Reference to the provider.
+         * \throw trrep::runtime_error if no providers are associated
+         *        with the client context.
          */
-        virtual int rollback(trrep::transaction_context&) = 0;
+        trrep::provider& provider() const;
 
-        virtual void will_replay(trrep::transaction_context&) { }
-        virtual int replay(trrep::unique_lock<trrep::mutex>&,
-                           trrep::transaction_context& tc);
+        /*!
+         * Get Client identifier.
+         *
+         * \return Client Identifier
+         */
+        client_id id() const { return id_; }
 
+        /*!
+         * Get Client mode.
+         *
+         * \todo Enforce mutex protection if called from other threads.
+         *
+         * \return Client mode.
+         */
+        enum mode mode() const { return mode_; }
 
-        virtual int apply(trrep::transaction_context&,
-                          const trrep::data&) = 0;
-
-        virtual void wait_for_replayers(trrep::unique_lock<trrep::mutex>&)
-        { }
-        virtual int prepare_data_for_replication(
-            const trrep::transaction_context&, trrep::data& data)
-        {
-            static const char buf[1] = { 1 };
-            data.assign(buf, 1);
-            return 0;
-        }
-        virtual void override_error(const trrep::client_error&) { }
-        virtual bool killed() const { return 0; }
-        virtual void abort() const { ::abort(); }
-        virtual void store_globals() { }
-        // Debug helpers
-        virtual void debug_sync(const std::string&)
-        {
-
-        }
-        virtual void debug_suicide(const std::string&)
-        {
-            abort();
-        }
     protected:
         /*!
-         * Client context constuctor
+         * Client context constuctor. This is protected so that it
+         * can be called from derived class constructors only.
          */
         client_context(trrep::mutex& mutex,
                        trrep::server_context& server_context,
@@ -293,6 +232,105 @@ namespace trrep
         { }
 
     private:
+        /*
+         * Friend declarations
+         */
+        friend int server_context::on_apply(client_context&,
+                                            trrep::transaction_context&,
+                                            const trrep::data&);
+        friend class client_context_switch;
+        friend class transaction_context;
+
+        /*!
+         * Get Client state.
+         *
+         * \todo Enforce mutex protection if called from other threads.
+         *
+         * \return Client state
+         */
+        enum state state() const { return state_; }
+
+        /*!
+         * Virtual method to return true if the client operates
+         * in two phase commit mode.
+         *
+         * \return True if two phase commit is required, false otherwise.
+         */
+        virtual bool do_2pc() const = 0;
+
+
+        /*!
+         * Append SR fragment to the transaction.
+         */
+        virtual int append_fragment(trrep::transaction_context&,
+                                    uint32_t, const trrep::data&)
+        { return 0; }
+
+
+        /*!
+         * This method applies a write set give in data buffer.
+         * This must be implemented by the DBMS integration.
+         *
+         * \return Zero on success, non-zero on applying failure.
+         */
+        virtual int apply(trrep::transaction_context& transaction,
+                          const trrep::data& data) = 0;
+
+        /*!
+         * Virtual method which will be called
+         * in order to commit the transaction into
+         * storage engine.
+         *
+         * \return Zero on success, non-zero on failure.
+         */
+        virtual int commit(trrep::transaction_context&) = 0;
+
+        /*!
+         * Rollback the transaction.
+         *
+         * This metod must be implemented by DBMS integration.
+         *
+         * \return Zero on success, no-zero on failure.
+         */
+        virtual int rollback(trrep::transaction_context&) = 0;
+
+        /*!
+         * Notify a implementation that the client is about
+         * to replay the transaction.
+         */
+        virtual void will_replay(trrep::transaction_context&) = 0;
+
+        /*!
+         * Replay the transaction.
+         */
+        virtual int replay(trrep::unique_lock<trrep::mutex>&,
+                           trrep::transaction_context& tc) = 0;
+
+
+        /*!
+         * Wait until all of the replaying transactions have been committed.
+         */
+        virtual void wait_for_replayers(trrep::unique_lock<trrep::mutex>&) const = 0;
+
+        virtual int prepare_data_for_replication(
+            const trrep::transaction_context&, trrep::data& data)
+        {
+            static const char buf[1] = { 1 };
+            data.assign(buf, 1);
+            return 0;
+        }
+
+        /*!
+         *
+         */
+        virtual void override_error(const trrep::client_error&) = 0;
+        virtual bool killed() const = 0;
+        virtual void abort() const = 0;
+        virtual void store_globals() = 0;
+        // Debug helpers
+        virtual void debug_sync(const std::string&) = 0;
+        virtual void debug_suicide(const std::string&) = 0;
+
         void state(enum state state);
 
         trrep::mutex& mutex_;
diff --git a/src/condition_variable.hpp b/src/condition_variable.hpp
index f5579d0..92544f9 100644
--- a/src/condition_variable.hpp
+++ b/src/condition_variable.hpp
@@ -7,6 +7,8 @@
 
 #include "lock.hpp"
 
+#include <cstdlib>
+
 namespace trrep
 {
     class condition_variable
@@ -23,7 +25,7 @@ namespace trrep
     };
 
     // Default pthreads based condition variable implementation
-    class default_condition_variable : condition_variable
+    class default_condition_variable : public condition_variable
     {
     public:
         default_condition_variable()
diff --git a/src/dbms_simulator.cpp b/src/dbms_simulator.cpp
index ea66505..3c1ead8 100644
--- a/src/dbms_simulator.cpp
+++ b/src/dbms_simulator.cpp
@@ -110,6 +110,7 @@ public:
                 const std::string& id,
                 const std::string& address)
         : trrep::server_context(mutex_,
+                                cond_,
                                 name, id, address, name + "_data",
                                 trrep::server_context::rm_async)
         , simulator_(simulator)
@@ -140,46 +141,6 @@ public:
         appliers_.erase(appliers_.begin());
     }
 
-    void on_connect()
-    {
-        std::cerr << "dbms_server: connected" << "\n";
-        trrep::unique_lock<trrep::mutex> lock(mutex_);
-        state_ = s_connected;
-        cond_.notify_all();
-    }
-
-    void on_view(const trrep::view& view)
-    {
-        std::cerr << "================================================\nView:\n"
-                  << "id: " << view.id() << "\n"
-                  << "status: " << view.status() << "\n"
-                  << "own_index: " << view.own_index() << "\n"
-                  << "final: " << view.final() << "\n"
-                  << "members: \n";
-        auto members(view.members());
-        for (const auto& m : members)
-        {
-            std::cerr << "id: " << m.id() << " "
-                      << "name: " << m.name() << "\n";
-
-        }
-        std::cerr << "=================================================\n";
-        trrep::unique_lock<trrep::mutex> lock(mutex_);
-        if (view.final())
-        {
-            state_ = s_disconnected;
-            cond_.notify_all();
-        }
-    }
-
-    void on_sync()
-    {
-        std::cerr << "Synced with group" << "\n";
-        trrep::unique_lock<trrep::mutex> lock(mutex_);
-        state_ = s_synced;
-        cond_.notify_all();
-    }
-
     bool sst_before_init() const override  { return false; }
     std::string on_sst_request()
     {
@@ -198,32 +159,6 @@ public:
         provider().sst_sent(gtid, 0);
     }
 
-    void wait_until_state(enum state state)
-    {
-        trrep::unique_lock<trrep::mutex> lock(mutex_);
-        while (state_ != state)
-        {
-            cond_.wait(lock);
-        }
-    }
-    void wait_until_connected()
-    {
-        trrep::unique_lock<trrep::mutex> lock(mutex_);
-        while (state_ != s_connected)
-        {
-            cond_.wait(lock);
-        }
-    }
-
-    void wait_until_disconnected()
-    {
-        trrep::unique_lock<trrep::mutex> lock(mutex_);
-        while (state_ != s_disconnected)
-        {
-            cond_.wait(lock);
-        }
-    }
-
     // Client context management
     trrep::client_context* local_client_context();
 
@@ -277,13 +212,14 @@ public:
         }
     }
 
-    bool do_2pc() const { return false; }
-    int apply(trrep::transaction_context&, const trrep::data&)
+private:
+    bool do_2pc() const override { return false; }
+    int apply(trrep::transaction_context&, const trrep::data&) override
     {
         // std::cerr << "applying" << "\n";
         return 0;
     }
-    int commit(trrep::transaction_context& transaction_context)
+    int commit(trrep::transaction_context& transaction_context) override
     {
         int ret(0);
         ret = transaction_context.before_commit();
@@ -292,7 +228,7 @@ public:
         // std::cerr << "commit" << "\n";
         return 0;
     }
-    int rollback(trrep::transaction_context& transaction_context)
+    int rollback(trrep::transaction_context& transaction_context) override
     {
         std::cerr << "rollback: " << transaction_context.id().get()
                   << "state: " << trrep::to_string(transaction_context.state())
@@ -301,7 +237,23 @@ public:
         transaction_context.after_rollback();
         return 0;
     }
-private:
+
+    void will_replay(trrep::transaction_context&) override { }
+    int replay(trrep::unique_lock<trrep::mutex>& lock,
+               trrep::transaction_context& tc) override
+    {
+        tc.state(lock, trrep::transaction_context::s_replaying);
+        tc.state(lock, trrep::transaction_context::s_committed);
+        return 0;
+    }
+    void wait_for_replayers(trrep::unique_lock<trrep::mutex>&) const override
+    { }
+    void override_error(const trrep::client_error&) override { }
+    bool killed() const override { return false; }
+    void abort() const override { ::abort(); }
+    void store_globals() override { }
+    void debug_sync(const std::string&) override { }
+    void debug_suicide(const std::string&) override { }
 
     void run_one_transaction()
     {
@@ -448,8 +400,7 @@ void dbms_simulator::start()
             throw trrep::runtime_error("Failed to connect");
         }
         server.start_applier();
-        server.wait_until_connected();
-        server.wait_until_state(dbms_server::s_synced);
+        server.wait_until_state(trrep::server_context::s_synced);
     }
 
     // Start client threads
@@ -487,7 +438,7 @@ void dbms_simulator::stop()
                  });
 
         server.provider().disconnect();
-        server.wait_until_disconnected();
+        server.wait_until_state(trrep::server_context::s_disconnected);
         server.stop_applier();
     }
 }
diff --git a/src/mock_client_context.hpp b/src/mock_client_context.hpp
index 8136716..9339843 100644
--- a/src/mock_client_context.hpp
+++ b/src/mock_client_context.hpp
@@ -7,6 +7,7 @@
 
 #include "client_context.hpp"
 #include "mutex.hpp"
+#include "compiler.hpp"
 
 namespace trrep
 {
@@ -28,6 +29,25 @@ namespace trrep
         int commit(trrep::transaction_context&);
         int rollback(trrep::transaction_context&);
         bool do_2pc() const { return do_2pc_; }
+        void will_replay(trrep::transaction_context&) TRREP_OVERRIDE { }
+        int replay(trrep::unique_lock<trrep::mutex>& lock,
+                   trrep::transaction_context& tc) TRREP_OVERRIDE
+        {
+            tc.state(lock, trrep::transaction_context::s_replaying);
+            tc.state(lock, trrep::transaction_context::s_committed);
+            return 0;
+        }
+        void wait_for_replayers(trrep::unique_lock<trrep::mutex>&) const
+            TRREP_OVERRIDE { }
+        void override_error(const trrep::client_error&) TRREP_OVERRIDE { }
+        bool killed() const TRREP_OVERRIDE { return false; }
+        void abort() const TRREP_OVERRIDE { }
+        void store_globals() TRREP_OVERRIDE { }
+        void debug_sync(const std::string&) TRREP_OVERRIDE { }
+        void debug_suicide(const std::string&) TRREP_OVERRIDE
+        {
+            ::abort();
+        }
 
         // Mock state modifiers
         void fail_next_applying(bool fail_next_applying)
diff --git a/src/mock_server_context.hpp b/src/mock_server_context.hpp
index e03ab43..0621f61 100644
--- a/src/mock_server_context.hpp
+++ b/src/mock_server_context.hpp
@@ -19,8 +19,10 @@ namespace trrep
         mock_server_context(const std::string& name,
                             const std::string& id,
                             enum trrep::server_context::rollback_mode rollback_mode)
-            : trrep::server_context(mutex_, name, id, "", "./", rollback_mode)
+            : trrep::server_context(mutex_, cond_,
+                                    name, id, "", "./", rollback_mode)
             , mutex_()
+            , cond_()
             , provider_()
             , last_client_id_(0)
         { }
@@ -47,6 +49,7 @@ namespace trrep
 
     private:
         trrep::default_mutex mutex_;
+        trrep::default_condition_variable cond_;
         mutable trrep::mock_provider provider_;
         unsigned long long last_client_id_;
     };
diff --git a/src/server_context.cpp b/src/server_context.cpp
index a469380..361a872 100644
--- a/src/server_context.cpp
+++ b/src/server_context.cpp
@@ -215,6 +215,55 @@ void trrep::server_context::sst_received(const wsrep_gtid_t& gtid)
     provider_->sst_received(gtid, 0);
 }
 
+void trrep::server_context::wait_until_state(
+    enum trrep::server_context::state state) const
+{
+    trrep::unique_lock<trrep::mutex> lock(mutex_);
+    while (state_ != state)
+    {
+        cond_.wait(lock);
+    }
+}
+
+void trrep::server_context::on_connect()
+{
+    std::cout << "Server " << name_ << " connected to cluster" << "\n";
+    trrep::unique_lock<trrep::mutex> lock(mutex_);
+    state_ = s_connected;
+    cond_.notify_all();
+}
+
+void trrep::server_context::on_view(const trrep::view& view)
+{
+    std::cout << "================================================\nView:\n"
+              << "id: " << view.id() << "\n"
+              << "status: " << view.status() << "\n"
+              << "own_index: " << view.own_index() << "\n"
+              << "final: " << view.final() << "\n"
+              << "members: \n";
+    const std::vector<trrep::view::member>& members(view.members());
+    for (std::vector<trrep::view::member>::const_iterator i(members.begin());
+         i != members.end(); ++i)
+    {
+        std::cout << "id: " << i->id() << " "
+                  << "name: " << i->name() << "\n";
+    }
+    std::cout << "=================================================\n";
+    trrep::unique_lock<trrep::mutex> lock(mutex_);
+    if (view.final())
+    {
+        state_ = s_disconnected;
+        cond_.notify_all();
+    }
+}
+
+void trrep::server_context::on_sync()
+{
+    std::cout << "Synced with group" << "\n";
+    trrep::unique_lock<trrep::mutex> lock(mutex_);
+    state_ = s_synced;
+    cond_.notify_all();
+}
 
 int trrep::server_context::on_apply(
     trrep::client_context& client_context,
diff --git a/src/server_context.hpp b/src/server_context.hpp
index 4fa1a5c..d48c3cf 100644
--- a/src/server_context.hpp
+++ b/src/server_context.hpp
@@ -67,6 +67,7 @@
 
 #include "exception.hpp"
 #include "mutex.hpp"
+#include "condition_variable.hpp"
 #include "wsrep_api.h"
 
 #include <string>
@@ -216,37 +217,43 @@ namespace trrep
             return *provider_;
         }
 
+
+
         /*!
          * Virtual method which will be called when the server
          * has been joined to the cluster. Must be provided by
          * the implementation.
-         */
-        virtual void on_connect() = 0;
-
-        /*!
-         * Wait until the server has connected to the cluster.
          *
-         * \todo This should not be pure virtual method,
-         * this base class should provide the server state
-         * machine and proper synchronization.
+         * \todo Document overriding.
          */
-        virtual void wait_until_connected() = 0;
+        virtual void on_connect();
 
         /*!
          * Virtual method which will be called when a view
          * notification event has been delivered by the
          * provider.
          *
+         * \todo Document overriding.
+         *
          * \params view trrep::view object which holds the new view
          *         information.
          */
-        virtual void on_view(const trrep::view& view) = 0;
+        virtual void on_view(const trrep::view& view);
 
         /*!
          * Virtual method which will be called when the server
          * has been synchronized with the cluster.
+         *
+         * \todo Document overriding.
          */
-        virtual void on_sync() = 0;
+        virtual void on_sync();
+
+        /*!
+         * Wait until server reaches given state.
+         *
+         * \todo Waiting for transitional states may not be reliable.
+         */
+        void wait_until_state(trrep::server_context::state) const;
 
         /*!
          * Virtual method to return true if the configured SST
@@ -336,12 +343,15 @@ namespace trrep
          * \param rollback_mode Rollback mode which server operates on.
          */
         server_context(trrep::mutex& mutex,
+                       trrep::condition_variable& cond,
                        const std::string& name,
                        const std::string& id,
                        const std::string& address,
                        const std::string& working_dir,
                        enum rollback_mode rollback_mode)
             : mutex_(mutex)
+            , cond_(cond)
+            , state_(s_disconnected)
             , provider_()
             , name_(name)
             , id_(id)
@@ -356,6 +366,8 @@ namespace trrep
         server_context& operator=(const server_context&);
 
         trrep::mutex& mutex_;
+        trrep::condition_variable& cond_;
+        enum state state_;
         trrep::provider* provider_;
         std::string name_;
         std::string id_;