Shortest Paths Based Web Service Selection in Internet of Things

Algorithm 4

Expanding neighbors with the same hops in BFSKNN.

BFSMapper (𝑅,𝐺):

(1)  for all  (𝑛𝑜𝑑𝑒,𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒) in 𝑅  do

(2)  emit(𝑛𝑜𝑑𝑒,𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒);

(3)  end for;

(4)  for all  (𝑓𝑟𝑜𝑚,𝑡𝑜) in 𝐺  do

(5)  emit(𝑡𝑜,𝑓𝑟𝑜𝑚.𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒+𝑤_{𝑓𝑟𝑜𝑚,𝑡𝑜});

(6)  end for;

BFSReducer  (output of BFSMapper):

(7)  for all  𝑘𝑒𝑦  do

(8)  let 𝑟𝑒𝑠𝑢𝑙𝑡(𝑘𝑒𝑦,𝑣𝑎𝑙𝑢𝑒)=(0,+∞);

(9)  for all  𝑣𝑎𝑙𝑢𝑒  do

(10)   if  𝑣𝑎𝑙𝑢𝑒<𝑟𝑒𝑠𝑢𝑙𝑡.𝑣𝑎𝑙𝑢𝑒  then

(11)    𝑟𝑒𝑠𝑢𝑙𝑡=(𝑘𝑒𝑦,𝑣𝑎𝑙𝑢𝑒);

(12)   end if

(13)  end for;

(14)  emit(𝑟𝑒𝑠𝑢𝑙𝑡);

(15) end for