Example: Bounded Buffers implemented using Monitors

Monitor BoundedBuffer;

var

Buffer:array[0..NumElts-1]of ElementType;

get,put,count:Integer;

NotFull,NotEmpty:Condition;

(* NotFull: Signaled when count<NumElts *)

(* NotEmpty: Signaled when count>0 *)

Procedure Entry Insert(Data:ElementType); Process Producer;

begin var

While count=n do Data:ElementType;

NotFull.wait; BB:BoundedBuffer;

Buffer[put]:=Data; begin

put:=(put+1)mod NumElts; While True do begin

count:=count+1; Produce(Data);

NotEmpty.signal; BB.Insert(Data);

end; end;

end.

Procedure Entry Remove(var Data:ElementType);

begin Process Consumer;

while count=0 do var

NotEmpty.wait; Data:ElementType;

Data:=Buffer[get]; BB:BoundedBuffer;

get:=(get+1)mod NumElts; begin

count:=count-1; While True do begin

NotFull.signal; BB.Remove(Data);

end; Consume(Data);

end;

begin (* Init Code *) end.

get:=0; put:=0; count:=0;

end;