[Mulgara-svn] r1323 - trunk/src/jar/tuples/java/org/mulgara/store/tuples

[pag at mulgara.org]

Author: pag
Date: 2008-10-15 22:23:20 -0700 (Wed, 15 Oct 2008)
New Revision: 1323

Modified:
   trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java
Log:
Found and fixed a pair of bugs when all variables are shared between two sides of an
optional join.  Also updated optionalJoin to handle left and right sides not sharing
variables (a cartesian product), and now handling projection to extra variables when
the optional part of a join is empty.
Fixes #152
Fixes #150


Modified: trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java
===================================================================
--- trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java	2008-10-16 05:14:34 UTC (rev 1322)
+++ trunk/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java	2008-10-16 05:23:20 UTC (rev 1323)
@@ -364,10 +364,8 @@
       // get the matching columns
       Set<Variable> matchingVars = getMatchingVars(standard, optional);
       // check for empty parameters
-      if (standard.getRowCardinality() == Cursor.ZERO) {
-        logger.debug("Nothing to the left of an optional");
-        return (Tuples)standard.clone();
-      }
+      if (standard.getRowCardinality() == Cursor.ZERO && logger.isDebugEnabled()) logger.debug("Nothing to the left of an optional");
+
       if (optional.getRowCardinality() == Cursor.ZERO) {
         // need to return standard, projected out to the extra variables
         if (optional.getNumberOfVariables() == 0) {
@@ -378,12 +376,16 @@
         }
       }
 
+      // If the Optional clause does not constrain the RHS
+      // then this is the equivalent to a normal join as a cartesian product
+      if (matchingVars.isEmpty()) return join(standard, optional);
+
       // check if there are variables which should not be considered when sorting
       if (!checkForExtraVariables(optional, matchingVars)) {
         // there were no extra variables in the optional
         logger.debug("All variables needed");
-        // if all variables match, then this is an inner join
-        return join(standard, optional);
+        // if all variables match, then the result is the same as the LHS
+        return (Tuples)standard.clone();
       }
 
       // yes, there are extra variables
@@ -897,7 +899,7 @@
   public static Tuples reSort(Tuples tuples, List<Variable> variableList) throws TuplesException {
     try {
       // if there is nothing to sort on, then tuples meets the criteria
-      if ((variableList == null) || (variableList.size() == 0)) return tuples;
+      if ((variableList == null) || (variableList.size() == 0)) return (Tuples)tuples.clone();
 
       // if there is nothing to sort, then just return that nothing
       if (tuples.isUnconstrained()) {
@@ -919,7 +921,7 @@
         // check that it is within the prefix columns. If not, then sorting is needed
         if (ti >= varMap.length) sortNeeded = true;
         // map the tuples index of the variable to the column index
-        varMap[varCol++] = ti;
+        varMap[varCol] = ti;
       }
 
       if (!sortNeeded) {