[Bigdata-commit] SF.net SVN: bigdata:[4268] branches/QUADS_QUERY_BRANCH/bigdata/src

[<tho...@us...>]

Revision: 4268
          http://bigdata.svn.sourceforge.net/bigdata/?rev=4268&view=rev
Author:   thompsonbry
Date:     2011-03-03 21:31:26 +0000 (Thu, 03 Mar 2011)

Log Message:
-----------
Optimization for BOpUtility#getSharedVariables() with unit test.

Modified Paths:
--------------
    branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/bop/BOpUtility.java
    branches/QUADS_QUERY_BRANCH/bigdata/src/test/com/bigdata/bop/util/TestBOpUtility_sharedVariables.java

Modified: branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/bop/BOpUtility.java
===================================================================
--- branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/bop/BOpUtility.java	2011-03-03 21:27:02 UTC (rev 4267)
+++ branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/bop/BOpUtility.java	2011-03-03 21:31:26 UTC (rev 4268)
@@ -1108,11 +1108,8 @@
 //        if (p == c)
 //            throw new IllegalArgumentException();
 
-        // The set of variables which are shared.
-        final Set<IVariable<?>> sharedVars = new LinkedHashSet<IVariable<?>>();
-
         // Collect the variables appearing anywhere in [p].
-        final Set<IVariable<?>> p1vars = new LinkedHashSet<IVariable<?>>();
+        Set<IVariable<?>> p1vars = null;
         {
 
             final Iterator<IVariable<?>> itr = BOpUtility
@@ -1120,12 +1117,29 @@
 
             while (itr.hasNext()) {
 
+            	if(p1vars == null) {
+            		 
+            		// lazy initialization.
+            		p1vars = new LinkedHashSet<IVariable<?>>();
+            		
+            	}
+            	
                 p1vars.add(itr.next());
 
             }
 
         }
 
+		if (p1vars == null) {
+		
+			// Fast path when no variables in [p].
+			return Collections.emptySet();
+			
+		}
+        
+        // The set of variables which are shared.
+        Set<IVariable<?>> sharedVars = null;
+
         // Consider the variables appearing anywhere in [c].
         {
 
@@ -1138,16 +1152,26 @@
 
                 if (p1vars.contains(avar)) {
 
-                    sharedVars.add(avar);
+					if (sharedVars == null) {
 
+						// lazy initialization.
+						sharedVars = new LinkedHashSet<IVariable<?>>();
+						
+					}
+					
+					sharedVars.add(avar);
+
                 }
 
             }
 
         }
 
-        return sharedVars;
+		if (sharedVars == null)
+			return Collections.emptySet();
 
+		return sharedVars;
+
     }
 
 }

Modified: branches/QUADS_QUERY_BRANCH/bigdata/src/test/com/bigdata/bop/util/TestBOpUtility_sharedVariables.java
===================================================================
--- branches/QUADS_QUERY_BRANCH/bigdata/src/test/com/bigdata/bop/util/TestBOpUtility_sharedVariables.java	2011-03-03 21:27:02 UTC (rev 4267)
+++ branches/QUADS_QUERY_BRANCH/bigdata/src/test/com/bigdata/bop/util/TestBOpUtility_sharedVariables.java	2011-03-03 21:31:26 UTC (rev 4268)
@@ -98,6 +98,14 @@
     @SuppressWarnings("unchecked")
     public void test_getSharedVariables_nothingShared() {
 
+        // nothing shared because no variables for one operand.
+        assertTrue(BOpUtility.getSharedVars(new Constant<Integer>(12), Var.var("y"))
+                .isEmpty());
+
+        // nothing shared because no variables for the other operand.
+        assertTrue(BOpUtility.getSharedVars(Var.var("y"),new Constant<Integer>(12))
+                .isEmpty());
+
         // nothing shared.
         assertTrue(BOpUtility.getSharedVars(Var.var("x"), Var.var("y"))
                 .isEmpty());


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