Data commit

Task/Rendezvous/Erlang/rendezvous.erl

@@ -0,0 +1,86 @@
+-module( rendezvous ).
+
+-export( [task/0] ).
+
+task() ->
+    Printer_pid = erlang:spawn( fun() -> printer(1, 5) end ),
+    Reserve_printer_pid = erlang:spawn( fun() -> printer(2, 5) end ),
+    Monitor_pid = erlang:spawn( fun() -> printer_monitor(Printer_pid, Reserve_printer_pid) end ),
+    erlang:spawn( fun() -> print(Monitor_pid, humpty_dumpty()) end ),
+    erlang:spawn( fun() -> print(Monitor_pid, mother_goose()) end ).
+
+humpty_dumpty() ->
+        ["Humpty Dumpty sat on a wall.",
+                "Humpty Dumpty had a great fall.",
+                "All the king's horses and all the king's men,",
+                "Couldn't put Humpty together again."].
+
+mother_goose() ->
+        ["Old Mother Goose,",
+               "When she wanted to wander,",
+               "Would ride through the air,",
+               "On a very fine gander.",
+               "Jack's mother came in,",
+               "And caught the goose soon,",
+               "And mounting its back,",
+               "Flew up to the moon."].
+
+print( Pid, Lines ) ->
+    io:fwrite( "Print ~p started~n", [erlang:self()] ),
+    print( Pid, Lines, infinity ).
+
+print( _Pid, [], _Timeout ) -> ok;
+print( Pid, [Line | T], Timeout ) ->
+    print_line( Pid, Line, Timeout ),
+    print_line_done(),
+    print( Pid, T, Timeout ).
+
+print_line( Pid, Line, Timeout ) ->
+    Pid ! {print, Line, erlang:self()},
+    receive
+    {print, started} -> ok
+    after Timeout -> erlang:throw( timeout )
+    end.
+
+print_line_done() ->
+    receive
+    {printer, ok} -> ok;
+    {printer, out_of_ink} -> erlang:throw( out_of_ink )
+    end.
+
+printer( N, 0 ) ->
+        receive
+        {print, _Line, Pid} -> Pid ! {printer, out_of_ink}
+        end,
+        printer( N, 0 );
+printer( N, Ink ) ->
+        receive
+        {print, Line, Pid} ->
+                Pid ! {printer, ok},
+                io:fwrite( "~p: ", [N] ),
+                [io:fwrite("~c", [X]) || X <- Line],
+                io:nl()
+        end,
+        printer( N, Ink - 1 ).
+
+printer_monitor( Printer, Reserve ) ->
+        {Line, Pid} = printer_monitor_get_line(),
+        Result = printer_monitor_print_line( Printer, Line ),
+        printer_monitor_reserve( Result, Reserve, Line, Pid ),
+        printer_monitor( Printer, Reserve ).
+
+printer_monitor_get_line() ->
+        receive
+        {print, Line, Pid} ->
+                Pid ! {print, started},
+                {Line, Pid}
+        end.
+
+printer_monitor_print_line( Printer_pid, Line ) ->
+        Printer_pid ! {print, Line, erlang:self()},
+        receive
+        {printer, Result} -> Result
+        end.
+
+printer_monitor_reserve( ok, _Reserve_pid, _Line, Pid ) -> Pid ! {printer, ok};
+printer_monitor_reserve( out_of_ink, Reserve_pid, Line, Pid ) -> Reserve_pid ! {print, Line, Pid}.