MATLAB: Preserve the methods of an object after it is updated

handleobjectvalue

 classdef AgentAlgorithm < handle 
    properties (GetAccess = 'public', SetAccess = 'private')
       Detections = []
       State = []
       Tracks = []
    end
    properties (GetAccess = 'public', SetAccess = 'private')    %PROTECTED
       Batch;   %Used to store previous states and properties
                %Batch(1) = T-1 state, Batch(2) = T-2 state, so on so forth
    end
    properties (Hidden, Constant)
        MaxBatchLength = 5;
    end
    methods 
        %Constructor of Agent 
        function Agent = AgentAlgorithm(State)
            Agent.State = State;
            NewBatch = Agent.CreateBatch([], [], []);
            Agent.Batch = NewBatch;
        end
        %New State & Detections initilizer for Agent
        function Agent = AgentUpdate(Agent, NewState, NewDetections)
            %Create last state Batch
            NewBatch = Agent.CreateBatch(Agent.Detections, Agent.Tracks, Agent.State);
            %If Batch is empty (Not initilized yet)
            if isempty(Agent.Batch(1).State)
                Obj.Batch = NewBatch;
            else
                Obj.Batch = [NewBatch Agent.Batch];
            end
            %Update with new parameters
            Obj.State = NewState;
            Obj.Detections = NewDetections; 
            Agent = Obj;
        end
    end
  methods (Static, Access = 'private')
        %Creates a new batch with given parameters
        function NewBatch = CreateBatch(Detections, Tracks, State) 
             NewBatch = struct('Detections', Detections,...
                'Tracks', Tracks, 'State', State);
        end
    end
 end
Question: When I call this object as follows:
 AAA = AgentAlgorithm(1)
 methods(AAA)
 Methods for class AgentAlgorithm:
 AgentAlgorithm  delete          findprop        isvalid         ne              
 AgentUpdate     eq              ge              le              notify          
 addlistener     findobj         gt              lt              
 AAA = AAA.AgentUpdate(2,3)
methods(AAA)
 Methods for class struct:
 amd          ctranspose   fieldnames   ichol        linsolve     permute      struct2cell  
 cholinc      display      fields       ilu          luinc        reshape      transpose
My problem is how can I use AgentUpdate(x,y) function such that at the end of I use this function, I still have the updated version of AAA object with all methods (AgentAlgorithm, AgentUpdate) after constructor called instead of a new AAA object w/o any user defined methods left. I used handle, did not work as I expected as you can see.

Best Answer

In your method AgentUpdate, don't use Obj. Just use AAA directly. Again, the way you wrote it now, Obj is a struct and when you do AAA=Obj at the end, your AAA becomes a struct.
function AgentUpdate(Agent, NewState, NewDetections)
    %Create last state Batch
    NewBatch = Agent.CreateBatch(Agent.Detections,...
                  Agent.Tracks, Agent.State);
      %If Batch is empty (Not initilized yet)
      if isempty(Agent.Batch(1).State)
          Agent.Batch = NewBatch;
      else
          Agent.Batch = [NewBatch Agent.Batch];
      end
      %Update with new parameters
      Agent.State = NewState;
      Agent.Detections = NewDetections; 
  end
In addition, because AgentAlgorithm is a handle class, in your definition of the method, you don't have to put Agent as the output.
Related Question