Logical Sensor Network: An Abstraction of Sensor Data Processing over Multidomain Sensor Network

Listing 3

Source code for construction and update for logical sensor network in Java.

1  public  class RainForecastNetwork extends LogicalSensorNetwork{

2 private  Source[][] rain;

3 private  LowpassFilter[][] lpf;

4 private  Average[] ave;

5 private  Direction dir;

6 public  RainForecastNetwork()  throws  Exception {

7  super(“conf/rain_forecast.lsn”);

8 }

9 @Override

10 public  boolean  onInit() {

11  rain = new  Source[2][]; //Logical Sensors

12  lpf = new  LowpassFilter[2][]; //Lowpass Filters

13  ave = new  Average[2]; //Average Aggregators

14  dir = new  Direction(“Direction”, new  TimerTrigger(10000));

15  //Instantiating Processor Nodes

16  for(int  i=0; i<2; i++){

17   rain[i] = manager.getNodes(“RainA” + (i+1));

18   lpf[i] = new  LowpassFilter[rain[i].length];

19   for(int  j=0; j<lpf[i].length; j++)

20    lpf[i][j] = new  LowpassFilter(“LPF”+i+j, new

21      FlowTrigger());

22   ave[i] = new  Average(“Ave” + i, new  RendezvousTrigger());

23  }

24  //Connecting Processor Nodes

25  for(int  i=0; i<2; i++){

26   for(int j=0; j<rain[i].length; j++){

27    rain[i][j].setPushStream(“value”, lpf[i][j]);

28    lpf[i][j].setPushStream(“value”, ave[i]);

29   }

30   ave[i].setPullStream(“value”, dir);

31  }

32  dir.setPushStream(“value”, sink);

33  return  true;

34 }

35 @Override

36 public  boolean onUpdate() {

37  //Disconnect Processor Nodes

38  for(int  i=0; i<2; i++){

39   for(int j=0; j<lpf[i].length; j++){

40    lpf[i][j].removeStream(ave[i]);

41   }

42  }

43  //Get new binding and instantiate new LowpassFilters

44  for(int  i=0; i<2; i++){

45   rain[i] = manager.getNodes(“RainA” + (i+1));

46   lpf[i] = new  LowpassFilter[rain[i].length];

47   for(int  j=0; j<lpf[i].length; j++)

48    lpf[i][j] = new  LowpassFilter(“LPF“+i+j, new

49      FlowTrigger());

50  }

51  //Connect new LowpassFilters to Averages

52  for(int  i=0; i<2; i++){

53   for(int j=0; j<rain[i].length; j++){

54    rain[i][j].setPushStream(“value”, lpf[i][j]);

55    lpf[i][j].setPushStream((“value”, ave[i]);

56   }

57  }

58  return  true;

59 }

60 }