Compositional Mining of Multiple Object API Protocols through State Abstraction

Algorithm 1

The algorithm to mine single object typestates annotated with interactions.

Input: 𝑇 as trace of events of an object 𝑜

     𝑆 as interaction specification of type 𝑡 of 𝑜

     𝑎𝑏𝑠 as the state abstract function

Output: 𝑀=(𝑄,Σ,𝛿,𝜆,𝑆,𝐹) as typestates for 𝑜

(1) initialize 𝑀 to be empty

(2) foreach event 𝑒=(𝑝𝑠₁,𝑚,𝑝𝑠₂)∈𝑇 in the order in 𝑇  do

(3)   𝑠₁=𝑎𝑏𝑠(𝑝𝑠₁.𝑜)

(4)  𝑠₂=𝑎𝑏𝑠(𝑝𝑠₂.𝑜)

(5)  create a transition 𝑡=(𝑠₁,𝑚,𝑠₂)

(6)  𝛿=𝛿∪𝑡

(7)   foreach interacting object 𝑜_𝑖 of 𝑜 when 𝑒 occurs do

(8)    𝑠_𝑖=𝑎𝑏𝑠(𝑝𝑠₁.𝑜_𝑖)

(9)   𝑠_𝑖^′=𝑎𝑏𝑠(𝑝𝑠₂.𝑜_𝑖)

(10)   increment frequency of 𝑠_𝑖→𝑠_𝑖^′ by 1

(11)    𝑓(𝑡)(𝑏⁻¹(𝑜_𝑖))=𝑓(𝑡)(𝑏⁻¹(𝑜_𝑖))∪{𝑠_𝑖→𝑠_𝑖^′}

(12)    if runtime type of 𝑜^′ is different from that in IS then

(13)      associate 𝑜_𝑖 to 𝑠_𝑖 and 𝑠_𝑖^′

(14)    endif

(15)   endfor

(16)  endfor

(17)  foreach 𝑡∈𝛿  do

(18)   foreach 𝑝∈𝑃_𝑡  do

(19)    𝜆(𝑡)(𝑝)=MAX(𝑓(𝑡)(𝑝))

(20)   endfor

(21)  endfor

(22)   return 𝑀