Shortest Paths Based Web Service Selection in Internet of Things

Algorithm 2

Expanding a nearest neighbor.

DijkstraMapper  (𝑅,𝐺):

(1)  for all  (𝑓𝑟𝑜𝑚,𝑡𝑜) in 𝐺  do

(2)  if  𝑓𝑟𝑜𝑚∈𝑅.𝑁𝑂𝐷𝐸∧𝑡𝑜∉𝑅.𝑁𝑂𝐷𝐸  then

(3)   emit(𝑓𝑟𝑜𝑚,𝑡𝑜);

(4)  end if

(5)  end for;

DijkstraReducer  (output of DijkstraMapper):

(6) let 𝑟𝑒𝑠𝑢𝑙𝑡(𝑘𝑒𝑦,𝑣𝑎𝑙𝑢𝑒)=(0,+∞);

(7)  for all  (𝑘𝑒𝑦,𝑣𝑎𝑙𝑢𝑒)  do

(8)  //find a nearest neighbour not in 𝑅;

(9)  if  𝑘𝑒𝑦∉𝑅.𝑁𝑂𝐷𝐸∧𝑣𝑎𝑙𝑢𝑒<𝑟𝑒𝑠𝑢𝑙𝑡.𝑣𝑎𝑙𝑢𝑒  then

(10)   𝑟𝑒𝑠𝑢𝑙𝑡=(𝑘𝑒𝑦,𝑣𝑎𝑙𝑢𝑒);

(11)   end if

(12)  end for;

(13)  return  𝑟𝑒𝑠𝑢𝑙𝑡