Matlab - Java communication: Reading java data stream

Question

Marcel Dorer 2018-1-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/376458-matlab-java-communication-reading-java-data-stream

编辑： Marcel Dorer 2018-1-10

I have a java based eye tracking program working together with a matlab based mini-game. Matlab receives the eye tracking data as a stream and saves it successfully to a new file. Now I want to receive the eye tracking data within matlab in real time to influence the mini game properties during the playtime. I tried a bunch of stuff but am unable to obtain the data from the data stream within my main matlab executable.

Java stream code within the main matlab executable:

    import java.net.Socket
    import java.io.*
    input_socket = Socket('localhost', 3999);
    [...]    
    output_stream = input_socket.getOutputStream;
    d_output_stream = DataOutputStream(output_stream);
    input_stream = input_socket.getInputStream;
    d_input_stream = DataInputStream(input_stream);
    [...]    
    EG_comm(d_output_stream, 'stop_sending');
    [...]    
    EG_log(d_output_stream, 'open', FileName);
    [...]    
    EG_log(d_output_stream, 'header', []);  
    [...]     
    EG_log(d_output_stream, 'start', []);
    [...] 
    EG_log(d_output_stream, 'mark', []);
    [...] 
    EG_log(d_output_stream, 'stop', []);
    [...] 
    EG_log(d_output_stream, 'close', []); 
    [...]     
    EG_comm(d_output_stream, 'close_and_recycle'); 
    [...]  
    d_input_stream.close
    input_stream.close
    d_output_stream.close
    output_stream.close
    input_socket.close

EG_comm function

function [error] = EG_comm(d_output_stream, message)
error = 0;
switch message
    case 'begin_sending'
        message= [0 0 5 30 35]; % begin sending gaze data to client
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;
    case 'stop_sending'
        message= [0 0 5 31 36]; % stop sending gaze data to client
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;
    case 'close_and_recycle'
        message= [0 0 5 32 37]; % close and restart server
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;   
    otherwise
        error = 1;
end

EG_log function

function [error] = EG_log(d_output_stream, message, filename)
error = 0;
switch message
    case 'open'
        message= [0 0 0 33 length(filename) uint8(filename) 1 uint8('w')];
        message(3)= length(message)+1;
        message(length(message)+1) = uint8(mod(sum(message),256));
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;
    case 'header'
        message= [0 0 5 34 39]; % write header
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;
    case 'start'
        message= [0 0 5 36 41]; % start logging
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;  
    case 'stop'
        message= [0 0 5 37 42]; % stop logging
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;
    case 'mark'
        message= [0 0 5 38 43]; % mark event
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;
    case 'close'
        message= [0 0 5 39 44]; % close file
        for i=1:length(message)
            d_output_stream.write(message(i),0,1);
        end
        d_output_stream.flush;
    otherwise
        error = 1;
end