How can I get a notification when my DataReader receives a ‘dispose’ sample with identity

Scenario:

I have UI application hosted on the remote machine. Server publishes data and UI Application(Remote) subscribe it continuously and populate data on UI.
If the server added a new record and published new data this data get subscribe through the UI application and populate on UI.

But I am facing problem with dispose data.  
If server delete sample DataReader:on_data_avilable get invoked but I can’t able to identify which sample is getting deleted. This sample I need to remove from UI.   

      @Override

        public void on_data_available(DataReader reader) {

            try {

                reader.take_untyped(

                    _dataSeq, _infoSeq,

                    ResourceLimitsQosPolicy.LENGTH_UNLIMITED,

                    SampleStateKind.ANY_SAMPLE_STATE,

                    ViewStateKind.ANY_VIEW_STATE,

                    InstanceStateKind.ANY_INSTANCE_STATE);

                for(int i = 0; i < _dataSeq.size(); ++i) {

                    SampleInfo info = (SampleInfo)_infoSeq.get(i);

                    //info.valid_data == true for new sample and false for dispose sample

                    if (info.valid_data) {

                        if(messageProcessor != null) {

                           messageProcessor.processMessage((_dataSeq.get(i)));

                        }

                    }

                }

            } catch (RETCODE_NO_DATA noData) {

                // No data to process

            } finally {

                reader.return_loan_untyped(_dataSeq, _infoSeq);

            }

        }