Shortest Paths Based Web Service Selection in Internet of Things

Algorithm 6

Expanding neighbors with the same hops in PruningBFSKNN.

PruningBFSKNNMapper (𝑅,𝐺):

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

(2)  emit(𝑛𝑜𝑑𝑒,𝑐𝐿𝑖𝑠𝑡,𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒);

(3)  end for;

(4)  for all  (𝑓𝑟𝑜𝑚,𝑡𝑜) in 𝐺  do

(5)  if  𝑓𝑟𝑜𝑚.𝑐𝐿𝑖𝑠𝑡∩𝐶≥𝑘  then

(6)   return;

(7)  else if  𝑓𝑟𝑜𝑚∈𝐶  then

(8)   𝑐𝐿𝑖𝑠𝑡=𝑐𝐿𝑖𝑠𝑡∪{𝑓𝑟𝑜𝑚}

(9)  end if;

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

(11)  end for;

PruningBFSKNNReducer (output of PruningBFSKNNMapper):

(12) for all  𝑘𝑒𝑦  do

(13)  Let 𝑟𝑒𝑠𝑢𝑙𝑡(𝑘𝑒𝑦,𝑐𝐿𝑖𝑠𝑡,𝑣𝑎𝑙𝑢𝑒)=(0,0,+∞);

(14)  for all  𝑣𝑎𝑙𝑢𝑒  do

(15)   if  𝑣𝑎𝑙𝑢𝑒<𝑟𝑒𝑠𝑢𝑙𝑡.𝑣𝑎𝑙𝑢𝑒  then

(16)    𝑟𝑒𝑠𝑢𝑙𝑡=(𝑘𝑒𝑦,𝑐𝐿𝑖𝑠𝑡,𝑣𝑎𝑙𝑢𝑒);

(17)   else if  𝑣𝑎𝑙𝑢𝑒==𝑟𝑒𝑠𝑢𝑙𝑡.𝑣𝑎𝑙𝑢𝑒∧𝑘𝑒𝑦.𝑐𝐿𝑖𝑠𝑡>|𝑟𝑒𝑠𝑢𝑙𝑡.𝑐𝐿𝑖𝑠𝑡|  then

(18)    𝑟𝑒𝑠𝑢𝑙𝑡=(𝑘𝑒𝑦,𝑐𝐿𝑖𝑠𝑡,𝑣𝑎𝑙𝑢𝑒);

(19)   end if;

(20)  end for;

(21)  emit(𝑟𝑒𝑠𝑢𝑙𝑡);

(22) end for