Logtalk 2.30.2 files.

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1908 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

Logtalk/examples/threads/buffer/NOTES.txt

@@ -1,6 +1,6 @@
 ================================================================
 Logtalk - Open source object-oriented logic programming language
-Release 2.30.1
+Release 2.30.2
 
 Copyright (c) 1998-2007 Paulo Moura.  All Rights Reserved.
 ================================================================

Logtalk/examples/threads/buffer/SCRIPT.txt

@@ -1,6 +1,6 @@
 ================================================================
 Logtalk - Open source object-oriented logic programming language
-Release 2.30.1
+Release 2.30.2
 
 Copyright (c) 1998-2007 Paulo Moura.  All Rights Reserved.
 ================================================================

Logtalk/examples/threads/buffer/buffer.lgt

@@ -1,34 +1,82 @@
 
-:- object(buffer).
+:- object(buffer(_MaxCapacity)).
+
+	:- info([
+		version is 2.0,
+		author is 'Paulo Moura',
+		date is 2007/6/20,
+		comment is 'Producer-consumer problem with a bounded buffer.']).
 
 	:- threaded.
 
-	:- public([put/1, get/1]).
+	:- public(put/1).
+	:- dynamic(put/1).
+	:- mode(put(?integer), one).
+	:- info(put/1, [
+		comment is 'Put an item in the buffer.']).
 
-	:- private(item/1).
-	:- dynamic(item/1).
+	:- public(get/1).
+	:- dynamic(get/1).
+	:- mode(get(?integer), one).
+	:- info(get/1, [
+		comment is 'Get an item from the buffer.']).
 
-	put(N) :-
-		(	N > 0										% wait until the previous item is consumed
-		->	NP is N - 1, threaded_wait(consumed(NP))	% (except for the first item!) 
-		;	true
-		),
-		assertz(item(N)),
+	:- private(item_/1).
+	:- dynamic(item_/1).
+
+	:- private(size_/1).
+	:- dynamic(size_/1).
+
+	size_(0).
+
+	put(Item) :-
+		parameter(1, MaxCapacity),
+		size_(N),
+		(	N =:= MaxCapacity ->		% if the maximum buffer capacity have been
+			threaded_wait(vacancy),		% reached, wait until an item is consumed
+			put(Item)					% be sure to consume all "vacancy" notifications before proceeding
+		;	put_item(Item),
+			(	N =:= 0 ->
+				threaded_notify(not_empty)
+			;	true
+			)
+		).
+
+	get(Item) :-
+		parameter(1, MaxCapacity),
+		size_(N),
+		(	N =:= 0 ->					% if the buffer is empty, wait
+			threaded_wait(not_empty),	% until an item is produced
+			get(Item)					% be sure to consume all "not_empty" notifications before proceeding
+		;	get_item(Item),
+			(	N =:= MaxCapacity ->
+				threaded_notify(vacancy)
+			;	true
+			)
+		).
+
+	:- synchronized([put_item/1, get_item/1]).
+
+	put_item(Item) :-
+		assertz(item_(Item)),
+		retract(size_(N)),
+		N2 is N + 1,
+		assertz(size_(N2)),
 		sender(Sender),
-		writeq(Sender), write(' wrote item '), write(N), nl,
-		threaded_notify(produced(N)).					% notify consumer that a new item is available
+		writeq(Sender), write(' stored item '), write(Item), nl.
 
-	get(N) :-
-		threaded_wait(produced(N)),						% wait until an item is available
-		retract(item(N)),
+	get_item(Item) :-
+		retract(item_(Item)),
+		retract(size_(N)),
+		N2 is N - 1,
+		assertz(size_(N2)),
 		sender(Sender),
-		writeq(Sender), write(' read item '), write(N), nl,
-		threaded_notify(consumed(N)).					% notify producer that the item was consumed
+		writeq(Sender), write(' consumed item '), write(Item), nl.
 
 :- end_object.
 
 
-:- object(producer).
+:- object(producer(_MaxTime)).
 
 	:- public(run/1).
 
@@ -38,16 +86,17 @@
 	run(N, N) :- !.
 	run(M, N) :-
 		M < N,
-		random::random(1, 5, Random),	% simulate a variable amount of 
-		thread_sleep(Random),			% time to produce a new item
-		buffer::put(M),
+		parameter(1, MaxTime),
+		random::random(1, MaxTime, Random),	% simulate a variable amount of 
+		thread_sleep(Random),				% time to produce a new item
+		buffer(7)::put(M),
 		M2 is M + 1,
 		run(M2, N).
 
 :- end_object.
 
 
-:- object(consumer).
+:- object(consumer(_MaxTime)).
 
 	:- public(run/1).
 
@@ -57,9 +106,10 @@
 	run(N, N) :- !.
 	run(M, N) :-
 		M < N,
-		random::random(1, 5, Random),	% simulate a variable amount of
-		thread_sleep(Random),			% time to consume an item
-		buffer::get(M),
+		parameter(1, MaxTime),
+		random::random(1, MaxTime, Random),	% simulate a variable amount of 
+		thread_sleep(Random),				% time to produce a new item
+		buffer(7)::get(_Item),
 		M2 is M + 1,
 		run(M2, N).