[Mulgara-svn] r1994 - trunk/src/jar/tuples/java/org/mulgara/store/tuples

[pag at mulgara.org]

Author: pag
Date: 2011-07-15 03:20:20 +0000 (Fri, 15 Jul 2011)
New Revision: 1994

Modified:
   trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java
Log:
Fixed OPTIONAL joins where the RHS is empty. It now returns the LHS projected to include the RHS columns (when possible)

Modified: trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java
===================================================================
--- trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java	2011-07-15 03:14:44 UTC (rev 1993)
+++ trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java	2011-07-15 03:20:20 UTC (rev 1994)
@@ -454,6 +454,17 @@
       // check for empty parameters
       if (logger.isDebugEnabled() && standard.getRowCardinality() == Cursor.ZERO) logger.debug("Nothing to the left of an optional");
 
+      // Checks if there is nothing on the RHS of the optional join
+      if (optional.isEmpty() || optional.getRowCardinality() == 0) {
+        // need to return standard, projected out to the extra variables
+        if (optional.getNumberOfVariables() == 0) {
+          // This may be empty due to having zero rows (since the columns are truncated in this case)
+          return (Tuples)standard.clone();
+        } else {
+          return project(standard, optional.getVariables());
+        }
+      }
+
       // If the Optional clause does not have matching variables with the LHS
       // then this is the equivalent to a normal join as a cartesian product
       if (matchingVars.isEmpty()) {
@@ -470,16 +481,6 @@
         return append(filteredProduct, invertedStd);
       }
 
-      if (optional.isEmpty()) {
-        // need to return standard, projected out to the extra variables
-        if (optional.getNumberOfVariables() == 0) {
-          // This may be empty due to having zero rows (since the columns are truncated in this case)
-          return (Tuples)standard.clone();
-        } else {
-          return project(standard, optional.getVariables());
-        }
-      }
-
       // check if there are variables which should not be considered when sorting
       if (!checkForExtraVariables(optional, matchingVars)) {
         // there were no extra variables in the optional