/***
         * Operations
         ***/
        public ITopic CreateSimulatedMultitopic(
        string name,
        string type_name,
        string subscription_expression,
        string[] expression_parameters)
        {
            /* Type-specific DDS entities */
            ChatMessageDataReader   chatMessageDR;
            NameServiceDataReader   nameServiceDR;
            NamedMessageDataWriter  namedMessageDW;

            /* Query related stuff */
            IQueryCondition          nameFinder;
            string[]                nameFinderParams;

            /* QosPolicy holders */
            TopicQos          namedMessageQos = new TopicQos();
            SubscriberQos     subQos          = new SubscriberQos();
            PublisherQos      pubQos          = new PublisherQos();

            /* Others */
            IDataReader              parentReader;
            IDataWriter              parentWriter;
            string                  partitionName   = "ChatRoom";
            string                  nameFinderExpr;
            ReturnCode                     status;

            /* Lookup both components that constitute the multi-topic. */
            chatMessageTopic = realParticipant.FindTopic(
            "Chat_ChatMessage", Duration.Infinite);
            ErrorHandler.checkHandle(
            chatMessageTopic,
            "DDS.DomainParticipant.FindTopic (Chat_ChatMessage)");

            nameServiceTopic = realParticipant.FindTopic(
            "Chat_NameService", Duration.Infinite);
            ErrorHandler.checkHandle(
            nameServiceTopic,
            "DDS.DomainParticipant.FindTopic (Chat_NameService)");

            /* Create a ContentFilteredTopic to filter out
               our own ChatMessages. */
            filteredMessageTopic = realParticipant.CreateContentFilteredTopic(
            "Chat_FilteredMessage",
            chatMessageTopic,
            "userID <> %0",
            expression_parameters);
            ErrorHandler.checkHandle(
            filteredMessageTopic,
            "DDS.DomainParticipant.CreateContentFilteredTopic");

            /* Adapt the default SubscriberQos to read from the
               "ChatRoom" Partition. */
            status = realParticipant.GetDefaultSubscriberQos (ref subQos);
            ErrorHandler.checkStatus(
            status, "DDS.DomainParticipant.GetDefaultSubscriberQos");
            subQos.Partition.Name = new string[1];
            subQos.Partition.Name[0] = partitionName;

            /* Create a private Subscriber for the multitopic simulator. */
            multiSub = realParticipant.CreateSubscriber(subQos);
            ErrorHandler.checkHandle(
            multiSub,
            "DDS.DomainParticipant.CreateSubscriber (for multitopic)");

            /* Create a DataReader for the FilteredMessage Topic
               (using the appropriate QoS). */
            DataReaderQos drQos = new DataReaderQos();
            TopicQos topicQos = new TopicQos();
            multiSub.GetDefaultDataReaderQos(ref drQos);
            filteredMessageTopic.RelatedTopic.GetQos(ref topicQos);
            multiSub.CopyFromTopicQos(ref drQos, topicQos);

            parentReader = multiSub.CreateDataReader(filteredMessageTopic, drQos);
            ErrorHandler.checkHandle(
            parentReader, "DDS.Subscriber.create_datareader (ChatMessage)");

            /* Narrow the abstract parent into its typed representative. */
            chatMessageDR = parentReader as ChatMessageDataReader;

            /* Allocate the DataReaderListener Implementation. */
            msgListener = new DataReaderListenerImpl();

            /* Attach the DataReaderListener to the DataReader,
               only enabling the data_available event. */
            status = chatMessageDR.SetListener(msgListener, StatusKind.DataAvailable);
            ErrorHandler.checkStatus(status, "DDS.DataReader_set_listener");

            /* Create a DataReader for the nameService Topic
               (using the appropriate QoS). */
            DataReaderQos nsDrQos = new DataReaderQos();
            TopicQos nsQos = new TopicQos();
            nameServiceTopic.GetQos(ref nsQos);
            multiSub.CopyFromTopicQos(ref nsDrQos, nsQos);

            parentReader = multiSub.CreateDataReader(nameServiceTopic, nsDrQos);
            ErrorHandler.checkHandle(parentReader, "DDS.Subscriber.CreateDatareader (NameService)");

            /* Narrow the abstract parent into its typed representative. */
            nameServiceDR = parentReader as NameServiceDataReader;

            /* Define the SQL expression (using a parameterized value). */
            nameFinderExpr = "userID = %0";

            /* Allocate and assign the query parameters. */
            nameFinderParams = new string[1];
            nameFinderParams[0] = expression_parameters[0];

            /* Create a QueryCondition to only read corresponding
               nameService information by key-value. */
            nameFinder = nameServiceDR.CreateQueryCondition(
            SampleStateKind.Any,
            ViewStateKind.Any,
            InstanceStateKind.Any,
            nameFinderExpr,
            nameFinderParams);
            ErrorHandler.checkHandle(
            nameFinder, "DDS.DataReader.create_querycondition (nameFinder)");

            /* Create the Topic that simulates the multi-topic
               (use Qos from chatMessage).*/
            status = chatMessageTopic.GetQos(ref namedMessageQos);
            ErrorHandler.checkStatus(status, "DDS.Topic.GetQos");

            /* Create the NamedMessage Topic whose samples simulate
               the MultiTopic */
            namedMessageTopic = realParticipant.CreateTopic(
            "Chat_NamedMessage",
            type_name,
            namedMessageQos);
            ErrorHandler.checkHandle(
            namedMessageTopic,
            "DDS.DomainParticipant.CreateTopic (NamedMessage)");

            /* Adapt the default PublisherQos to write into the
               "ChatRoom" Partition. */
            status = realParticipant.GetDefaultPublisherQos(ref pubQos);
            ErrorHandler.checkStatus(
            status, "DDS.DomainParticipant.get_default_publisher_qos");
            pubQos.Partition.Name = new string[1];
            pubQos.Partition.Name[0] = partitionName;

            /* Create a private Publisher for the multitopic simulator. */
            multiPub = realParticipant.CreatePublisher(pubQos);
            ErrorHandler.checkHandle(
            multiPub,
            "DDS.DomainParticipant.create_publisher (for multitopic)");

            DataWriterQos nmDwQos = new DataWriterQos();
            TopicQos nmQos = new TopicQos();
            multiPub.GetDefaultDataWriterQos(ref nmDwQos);
            namedMessageTopic.GetQos(ref nmQos);
            multiPub.CopyFromTopicQos(ref nmDwQos, nmQos);

            /* Create a DataWriter for the multitopic. */
            parentWriter = multiPub.CreateDataWriter(namedMessageTopic, nmDwQos);
            ErrorHandler.checkHandle(
            parentWriter, "DDS.Publisher.CreateDatawriter (NamedMessage)");

            /* Narrow the abstract parent into its typed representative. */
            namedMessageDW = parentWriter as NamedMessageDataWriter;

            /* Store the relevant Entities in our Listener. */
            msgListener.ChatMessageDR = chatMessageDR;
            msgListener.NameServiceDR = nameServiceDR;
            msgListener.NamedMessageDW = namedMessageDW;
            msgListener.NameFinder = nameFinder;
            msgListener.NameFinderParams = nameFinderParams;

            /* Return the simulated Multitopic. */
            return namedMessageTopic;
        }
        /***
         * Operations
         ***/
        public ITopic CreateSimulatedMultitopic(
            string name,
            string type_name,
            string subscription_expression,
            string[] expression_parameters)
        {
            /* Type-specific DDS entities */
            ChatMessageDataReader  chatMessageDR;
            NameServiceDataReader  nameServiceDR;
            NamedMessageDataWriter namedMessageDW;

            /* Query related stuff */
            IQueryCondition nameFinder;

            string[] nameFinderParams;

            /* QosPolicy holders */
            TopicQos      namedMessageQos = new TopicQos();
            SubscriberQos subQos          = new SubscriberQos();
            PublisherQos  pubQos          = new PublisherQos();

            /* Others */
            IDataReader parentReader;
            IDataWriter parentWriter;
            string      partitionName = "ChatRoom";
            string      nameFinderExpr;
            ReturnCode  status;

            /* Lookup both components that constitute the multi-topic. */
            chatMessageTopic = realParticipant.FindTopic(
                "Chat_ChatMessage", Duration.Infinite);
            ErrorHandler.checkHandle(
                chatMessageTopic,
                "DDS.DomainParticipant.FindTopic (Chat_ChatMessage)");

            nameServiceTopic = realParticipant.FindTopic(
                "Chat_NameService", Duration.Infinite);
            ErrorHandler.checkHandle(
                nameServiceTopic,
                "DDS.DomainParticipant.FindTopic (Chat_NameService)");

            /* Create a ContentFilteredTopic to filter out
             * our own ChatMessages. */
            filteredMessageTopic = realParticipant.CreateContentFilteredTopic(
                "Chat_FilteredMessage",
                chatMessageTopic,
                "userID <> %0",
                expression_parameters);
            ErrorHandler.checkHandle(
                filteredMessageTopic,
                "DDS.DomainParticipant.CreateContentFilteredTopic");

            /* Adapt the default SubscriberQos to read from the
             * "ChatRoom" Partition. */
            status = realParticipant.GetDefaultSubscriberQos(ref subQos);
            ErrorHandler.checkStatus(
                status, "DDS.DomainParticipant.GetDefaultSubscriberQos");
            subQos.Partition.Name    = new string[1];
            subQos.Partition.Name[0] = partitionName;

            /* Create a private Subscriber for the multitopic simulator. */
            multiSub = realParticipant.CreateSubscriber(subQos);
            ErrorHandler.checkHandle(
                multiSub,
                "DDS.DomainParticipant.CreateSubscriber (for multitopic)");

            /* Create a DataReader for the FilteredMessage Topic
             * (using the appropriate QoS). */
            DataReaderQos drQos    = new DataReaderQos();
            TopicQos      topicQos = new TopicQos();

            multiSub.GetDefaultDataReaderQos(ref drQos);
            filteredMessageTopic.RelatedTopic.GetQos(ref topicQos);
            multiSub.CopyFromTopicQos(ref drQos, topicQos);

            parentReader = multiSub.CreateDataReader(filteredMessageTopic, drQos);
            ErrorHandler.checkHandle(
                parentReader, "DDS.Subscriber.create_datareader (ChatMessage)");

            /* Narrow the abstract parent into its typed representative. */
            chatMessageDR = parentReader as ChatMessageDataReader;

            /* Allocate the DataReaderListener Implementation. */
            msgListener = new DataReaderListenerImpl();

            /* Attach the DataReaderListener to the DataReader,
             * only enabling the data_available event. */
            status = chatMessageDR.SetListener(msgListener, StatusKind.DataAvailable);
            ErrorHandler.checkStatus(status, "DDS.DataReader_set_listener");

            /* Create a DataReader for the nameService Topic
             * (using the appropriate QoS). */
            DataReaderQos nsDrQos = new DataReaderQos();
            TopicQos      nsQos   = new TopicQos();

            status = multiSub.GetDefaultDataReaderQos(ref nsDrQos);
            ErrorHandler.checkStatus(status, "DDS.Subscriber.GetDefaultDataReaderQos");
            nameServiceTopic.GetQos(ref nsQos);
            multiSub.CopyFromTopicQos(ref nsDrQos, nsQos);

            parentReader = multiSub.CreateDataReader(nameServiceTopic, nsDrQos);
            ErrorHandler.checkHandle(parentReader, "DDS.Subscriber.CreateDatareader (NameService)");

            /* Narrow the abstract parent into its typed representative. */
            nameServiceDR = parentReader as NameServiceDataReader;

            /* Define the SQL expression (using a parameterized value). */
            nameFinderExpr = "userID = %0";

            /* Allocate and assign the query parameters. */
            nameFinderParams    = new string[1];
            nameFinderParams[0] = expression_parameters[0];

            /* Create a QueryCondition to only read corresponding
             * nameService information by key-value. */
            nameFinder = nameServiceDR.CreateQueryCondition(
                SampleStateKind.Any,
                ViewStateKind.Any,
                InstanceStateKind.Any,
                nameFinderExpr,
                nameFinderParams);
            ErrorHandler.checkHandle(
                nameFinder, "DDS.DataReader.create_querycondition (nameFinder)");

            /* Create the Topic that simulates the multi-topic
             * (use Qos from chatMessage).*/
            status = chatMessageTopic.GetQos(ref namedMessageQos);
            ErrorHandler.checkStatus(status, "DDS.Topic.GetQos");

            /* Create the NamedMessage Topic whose samples simulate
             * the MultiTopic */
            namedMessageTopic = realParticipant.CreateTopic(
                "Chat_NamedMessage",
                type_name,
                namedMessageQos);
            ErrorHandler.checkHandle(
                namedMessageTopic,
                "DDS.DomainParticipant.CreateTopic (NamedMessage)");

            /* Adapt the default PublisherQos to write into the
             * "ChatRoom" Partition. */
            status = realParticipant.GetDefaultPublisherQos(ref pubQos);
            ErrorHandler.checkStatus(
                status, "DDS.DomainParticipant.get_default_publisher_qos");
            pubQos.Partition.Name    = new string[1];
            pubQos.Partition.Name[0] = partitionName;

            /* Create a private Publisher for the multitopic simulator. */
            multiPub = realParticipant.CreatePublisher(pubQos);
            ErrorHandler.checkHandle(
                multiPub,
                "DDS.DomainParticipant.create_publisher (for multitopic)");

            DataWriterQos nmDwQos = new DataWriterQos();
            TopicQos      nmQos   = new TopicQos();

            multiPub.GetDefaultDataWriterQos(ref nmDwQos);
            namedMessageTopic.GetQos(ref nmQos);
            multiPub.CopyFromTopicQos(ref nmDwQos, nmQos);

            /* Create a DataWriter for the multitopic. */
            parentWriter = multiPub.CreateDataWriter(namedMessageTopic, nmDwQos);
            ErrorHandler.checkHandle(
                parentWriter, "DDS.Publisher.CreateDatawriter (NamedMessage)");

            /* Narrow the abstract parent into its typed representative. */
            namedMessageDW = parentWriter as NamedMessageDataWriter;

            /* Store the relevant Entities in our Listener. */
            msgListener.ChatMessageDR    = chatMessageDR;
            msgListener.NameServiceDR    = nameServiceDR;
            msgListener.NamedMessageDW   = namedMessageDW;
            msgListener.NameFinder       = nameFinder;
            msgListener.NameFinderParams = nameFinderParams;

            /* Return the simulated Multitopic. */
            return(namedMessageTopic);
        }