[Mulgara-svn] r845 - branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples

[pag at mulgara.org]

Author: pag
Date: 2008-04-24 10:32:51 -0700 (Thu, 24 Apr 2008)
New Revision: 845

Modified:
   branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/FilteredTuples.java
Log:
Updates filters with context whenever testing, as the Tuples and context may be cloned, but the filters are not

Modified: branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/FilteredTuples.java
===================================================================
--- branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/FilteredTuples.java	2008-04-24 08:48:52 UTC (rev 844)
+++ branches/mgr-61-sparql/src/jar/tuples/java/org/mulgara/store/tuples/FilteredTuples.java	2008-04-24 17:32:51 UTC (rev 845)
@@ -61,21 +61,21 @@
   protected Filter filter;
 
   /** The tuples context */
-  protected Context context;
+  protected TuplesContext context;
 
   /**
    * Configure a tuples for filtering.
    *
    * @param unfiltered The original tuples.
    * @param filter The filter to apply.
-   * @param context The context to evaluate the tuples in.
+   * @param queryContext The context to evaluate the tuples in.
    * @throws IllegalArgumentException If the <var>unfiltered</var> tuples is null.
    */
-  FilteredTuples(Tuples unfiltered, Filter filter, QueryEvaluationContext context) throws IllegalArgumentException {
+  FilteredTuples(Tuples unfiltered, Filter filter, QueryEvaluationContext queryContext) throws IllegalArgumentException {
     // store the operands
     this.filter = filter;
     this.unfiltered = (Tuples)unfiltered.clone();
-    this.context = new TuplesContext(this.unfiltered, context.getResolverSession());
+    this.context = new TuplesContext(this.unfiltered, queryContext.getResolverSession());
     filter.setContextOwner(this);
   }
 
@@ -151,7 +151,7 @@
     unfiltered.beforeFirst(prefix, suffixTruncation);
   }
 
-
+  
   /**
    * @return {@inheritDoc}
    * @throws TuplesException {@inheritDoc}
@@ -164,7 +164,7 @@
         // Short-circuit execution if this tuples' cursor is after the last row
         if (!currentNext) return false;
         // check if the filter passes the current row on the unfiltered
-      } while (!filter.test(context));
+      } while (!testFilter());
     } catch (QueryException qe) {
       throw new TuplesException("Unable to iterate to the next tuples element while filtering", qe);
     }
@@ -183,12 +183,9 @@
   public Object clone() {
     FilteredTuples cloned = (FilteredTuples)super.clone();
 
-    // Copy mutable fields by value
+    // Clone the mutable fields as well
     cloned.unfiltered = (Tuples)unfiltered.clone();
-    // update the tuples in the context to the new value
-    if (context instanceof TuplesContext) {
-      ((TuplesContext)cloned.context).setTuples(cloned.unfiltered);
-    }
+    cloned.context = new TuplesContext(cloned.unfiltered, context);
     return cloned;
   }
 
@@ -207,7 +204,18 @@
    * @see org.mulgara.query.filter.ContextOwner#setCurrentContext(org.mulgara.query.filter.Context)
    */
   public void setCurrentContext(Context context) {
-    this.context = context;
+    if (!(context instanceof TuplesContext)) throw new IllegalArgumentException("FilteredTuples can only accept a TuplesContext.");
+    this.context = (TuplesContext)context;
   }
 
+  /**
+   * Tests a filter using the current context.
+   * @return The test result.
+   * @throws QueryException If there was an error accessing data needed for the test.
+   */
+  private boolean testFilter() throws QueryException {
+    // re-root the filter expression to this Tuples
+    filter.setContextOwner(this);
+    return filter.test(context);
+  }
 }