MONDRIAN: CastFunDef can throw exceptions when the cell is not loaded…

… yet. This causes RolapResult.executeBody() to fail. Now CastFunDef will return NULL instead.

[git-p4: depot-paths = "//open/mondrian/": change = 8482]

src/main/mondrian/olap/fun/CastFunDef.java

@@ -16,6 +16,7 @@
 import mondrian.calc.ExpCompiler;
 import mondrian.calc.impl.GenericCalc;
 import mondrian.mdx.ResolvedFunCall;
+import mondrian.olap.fun.FunUtil;
 
 /**
  * Definition of the <code>CAST</code> MDX operator.
@@ -67,6 +68,9 @@ public String evaluateString(Evaluator evaluator) {
 
             public int evaluateInteger(Evaluator evaluator) {
                 final Object o = evaluate(evaluator);
+                if (o == null) {
+                    return FunUtil.IntegerNull;
+                }                
                 if (o instanceof String) {
                     return Integer.parseInt((String) o);
                 }
@@ -78,6 +82,9 @@ public int evaluateInteger(Evaluator evaluator) {
 
             public double evaluateDouble(Evaluator evaluator) {
                 final Object o = evaluate(evaluator);
+                if (o == null) {
+                    return FunUtil.DoubleNull;
+                }                                
                 if (o instanceof String) {
                     return Double.valueOf((String) o);
                 }
@@ -89,6 +96,9 @@ public double evaluateDouble(Evaluator evaluator) {
 
             public boolean evaluateBoolean(Evaluator evaluator) {
                 final Object o = evaluate(evaluator);
+                if (o == null) {
+                    return FunUtil.BooleanNull;
+                }                                                
                 if (o instanceof Boolean) {
                     return (Boolean) o;
                 }

testsrc/main/mondrian/olap/fun/FunctionTest.java

@@ -6771,18 +6771,17 @@ public void testCast() {
         // To boolean (trivial)
         assertExprReturns("1=1 AND Cast(1 = 1 AND 1 = 2 AS Boolean)", "false");
 
-        // From null
-        // To Integer
-        assertExprThrows("0 + Cast(NULL AS Integer)",
-            "cannot convert value 'null' to targetType 'DECIMAL(0)'");
-        // To Numeric
-        assertExprThrows("0 + Cast(NULL AS Numeric)",
-            "cannot convert value 'null' to targetType 'NUMERIC'");
-        // To String
+        // From null : should not throw exceptions since RolapResult.executeBody can receive NULL
+        // values when the cell value is not loaded yet, so should return null instead.        
+        // To Integer : Expect to return NULL
+        assertExprReturns("0 * Cast(NULL AS Integer)", "");  // Expect to return NULL
+        // To Numeric : Expect to return NULL
+        assertExprReturns("0 * Cast(NULL AS Numeric)", "");  // Expect to return NULL
+        // To String : Expect to return "null"
         assertExprReturns("'' || Cast(NULL AS String)", "null");
-        // To Boolean
-        assertExprThrows("1=1 AND Cast(NULL AS Boolean)",
-            "cannot convert value 'null' to targetType 'BOOLEAN'");
+        // To Boolean : Expect to return NULL, but since FunUtil.BooleanNull does not 
+        // implement three-valued boolean logic yet, this will return false
+        assertExprReturns("1=1 AND Cast(NULL AS Boolean)", "false");
 
         // Double is not allowed as a type
         assertExprThrows("Cast(1 AS Double)",