From de2d6fa64af49156db6328db775aa33c876e2348 Mon Sep 17 00:00:00 2001
From: Jan Philipp Timme <jan.philipp@timme.it>
Date: Thu, 29 Sep 2016 18:28:36 +0200
Subject: [PATCH] [TASK] Use FILTER NOT EXISTS instead of OPTIONAL juggling.

---
 src/main/java/lu/jpt/csparqltest/Main.java | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/main/java/lu/jpt/csparqltest/Main.java b/src/main/java/lu/jpt/csparqltest/Main.java
index 06a1794..d48d8a3 100644
--- a/src/main/java/lu/jpt/csparqltest/Main.java
+++ b/src/main/java/lu/jpt/csparqltest/Main.java
@@ -148,14 +148,11 @@ public class Main {
 				+ " BIND(f:timestamp(?a,rdf:type,<http://example.org/type/A>) AS ?tsa) "
 				+ " BIND(f:timestamp(?c,rdf:type,<http://example.org/type/C>) AS ?tsc) "
 				+ " FILTER(?tsa < ?tsc) "
-				+ " OPTIONAL {"
+				+ " FILTER NOT EXISTS { "
 				+ "  ?b a <http://example.org/type/B> . "
 				+ "  BIND(f:timestamp(?b,rdf:type,<http://example.org/type/B>) AS ?tsb) "
-				+ "  FILTER(?tsb < ?tsa || ?tsc < ?tsb)"
+				+ "  FILTER(?tsa < ?tsb && ?tsb < ?tsc)"
 				+ " } "
-				//+ " BIND(BOUND(?b) AS ?bbound) "
-				//+ " BIND(?tsa < ?tsb AS ?abeforeb) "
-				//+ " BIND(?tsb < ?tsc AS ?bbeforec) "
 				+ "}";
 	}