[Mulgara-svn] r854 - branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples

[pag at mulgara.org]

Author: pag
Date: 2008-04-24 21:16:48 -0700 (Thu, 24 Apr 2008)
New Revision: 854

Modified:
   branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java
Log:
Reworked the reSort method to use standard operations, abandoning the PartialColumnComparator. Added a new optionalJoin operation to recursively handle lists of operators.

Modified: branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java
===================================================================
--- branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java	2008-04-25 04:14:34 UTC (rev 853)
+++ branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/TuplesOperations.java	2008-04-25 04:16:48 UTC (rev 854)
@@ -335,11 +335,28 @@
       logger.warn("RuntimeException thrown in subtraction", re);
       throw re;
     } catch (TuplesException te) {
-      logger.warn("TuplesException thrown in substraction", te);
+      logger.warn("TuplesException thrown in subtraction", te);
       throw te;
     }
   }
 
+  /**
+   * Does a left-associative optionalJoin along a list of arguments.
+   * @param args The arguments to operate on.
+   * @return A tuples containing all of the entries from args.get(0) and matching
+   *   entries from the remainder of the list. All variables from the entire list
+   *   will be present in the result.
+   * @throws TuplesException On error accessing elements in any argument.
+   */
+  public static Tuples optionalJoin(LinkedList<Tuples> args) throws TuplesException {
+    // check for termination. The first couple are for <NIL> syntax elements in the query
+    if (args.size() == 0) return empty();
+    if (args.size() == 1) return args.get(0);
+    if (args.size() == 2) return optionalJoin(args.get(0), args.get(1));
+    // join the head of the list, and then iterate
+    args.addFirst(optionalJoin(args.removeFirst(), args.removeFirst()));
+    return optionalJoin(args);
+  }
 
   /**
    * Does a left-outer-join between two tuples. Parameters are not closed during this
@@ -914,17 +931,32 @@
         varMap[varCol++] = ti;
       }
 
-      if (logger.isDebugEnabled()) logger.debug("No sort needed on tuples.");
-      if (!sortNeeded) return tuples;
+      if (!sortNeeded) {
+        if (logger.isDebugEnabled()) logger.debug("No sort needed on tuples.");
+        return tuples;
+      }
       
       if (logger.isDebugEnabled()) logger.debug("Sorting on " + variableList);
 
-      // Perform the actual sort
+      // append the remaining variables to the list of variables to sort on
+      List<Variable> fullVarList = new ArrayList<Variable>(variableList);
+      for (Variable v: tuples.getVariables()) {
+        if (!variableList.contains(v)) fullVarList.add(v);
+      }
+      assert fullVarList.containsAll(Arrays.asList(tuples.getVariables()));
+
+      // Reorder the columns - the projection here does not remove any columns
       Tuples oldTuples = tuples;
-      tuples = tuplesFactory.newTuples(tuples, new PartialColumnComparator(varMap));
+      tuples = new UnorderedProjection(tuples, fullVarList);
       assert tuples != oldTuples;
       oldTuples.close();
 
+      // Perform the actual sort
+      oldTuples = tuples;
+      tuples = tuplesFactory.newTuples(tuples);
+      assert tuples != oldTuples;
+      oldTuples.close();
+
       return tuples;
     } catch (TuplesException e) {
       throw new TuplesException("Couldn't perform projection", e);