%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Simulate a simple workflow. %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% The simulate transaction creates and executes a workflow instance
% for every work item, W.
%

simulate :- getItem(W) * (workflow(W) # simulate).


simulate :- finished.

% Work items are stored in the predicate source/1.
%
getItem(W) :- del(source(W)).


% The transaction workflow(W) applies the workflow to work item W.
% The workflow itself is a sequence of three tasks.
%

workflow(W) :- task(W,1) * task(W,2) * task(W,3).

% Transaction task(I,W) applies task I to work item W.  Since this is
% a simulation, the task does nothing but monitor its own execution.
%

task(I,W) :- monitor(task(I,W)).


% Create some work items.
%

load1 :- ins(source(a)).

load2 :- ins(source(a)) * ins(source(b)).

load3 :- ins(source(a)) * ins(source(b)) * ins(source(c)) * ins(source(d)) *
         ins(source(e)) * ins(source(f)) * ins(source(g)) * ins(source(h)) *
         ins(source(i)) * ins(source(j)).