From 8b8d2d39b2d79cd4005d8105c57fa81be7467a6b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timo=20Westk=C3=A4mper?= <timo.westkamper@mysema.com>
Date: Tue, 21 Apr 2009 12:43:05 +0000
Subject: [PATCH] added better error reporting

---
 .../collections/eval/JaninoEvaluator.java     | 19 ++++++++++++++++---
 .../iterators/FilteringMultiIterator.java     |  2 +-
 .../mysema/query/collections/AliasTest.java   |  2 +-
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/querydsl-collections/src/main/java/com/mysema/query/collections/eval/JaninoEvaluator.java b/querydsl-collections/src/main/java/com/mysema/query/collections/eval/JaninoEvaluator.java
index 38f60b7c7..f92ec9103 100644
--- a/querydsl-collections/src/main/java/com/mysema/query/collections/eval/JaninoEvaluator.java
+++ b/querydsl-collections/src/main/java/com/mysema/query/collections/eval/JaninoEvaluator.java
@@ -24,14 +24,22 @@ public class JaninoEvaluator implements Evaluator{
 
     private final ExpressionEvaluator ev;
     
-    public JaninoEvaluator(ExpressionEvaluator ev){
+    private final Expr<?> projection;
+    
+    private final List<? extends Expr<?>> sources;
+    
+    public JaninoEvaluator(ExpressionEvaluator ev, List<? extends Expr<?>> sources, Expr<?> projection){
         this.ev = Assert.notNull(ev);
+        this.sources = sources;
+        this.projection = projection;        
     }
     
     public JaninoEvaluator(JavaOps ops, List<? extends Expr<?>> sources, Expr<?> expr){
         try {
             Class<?> type = expr.getType() != null ? expr.getType() : Object.class;
-            ev = new JavaSerializer(ops).handle(expr).createExpressionEvaluator(sources, type);
+            this.ev = new JavaSerializer(ops).handle(expr).createExpressionEvaluator(sources, type);
+            this.sources = sources;
+            this.projection = expr;
         } catch (Exception e) {
             throw new RuntimeException(e.getMessage(), e);
         }
@@ -43,7 +51,12 @@ public class JaninoEvaluator implements Evaluator{
             return (T)ev.evaluate(args);
         } catch (InvocationTargetException e) {
             if (e.getCause() instanceof NullPointerException){
-                throw new IllegalArgumentException("null path in expression");
+                for (int i=0; i < args.length; i++){
+                    if (args[i] == null){
+                        throw new IllegalArgumentException("null for " + sources.get(i));        
+                    }
+                }
+                throw new IllegalArgumentException("null in " + projection);
             }else{
                 throw new RuntimeException(e.getMessage(), e);    
             }            
diff --git a/querydsl-collections/src/main/java/com/mysema/query/collections/iterators/FilteringMultiIterator.java b/querydsl-collections/src/main/java/com/mysema/query/collections/iterators/FilteringMultiIterator.java
index ac4b2bf63..b2314af71 100644
--- a/querydsl-collections/src/main/java/com/mysema/query/collections/iterators/FilteringMultiIterator.java
+++ b/querydsl-collections/src/main/java/com/mysema/query/collections/iterators/FilteringMultiIterator.java
@@ -81,7 +81,7 @@ public class FilteringMultiIterator extends MultiIterator implements IteratorSou
         logger.info("Filtering iterator for source");
         ExpressionEvaluator ev = serializer.createExpressionEvaluator(sources, boolean.class);
         if (ev != null){
-            return new JaninoEvaluator(ev);    
+            return new JaninoEvaluator(ev, sources, where);    
         }else{
             return null;
         }
diff --git a/querydsl-collections/src/test/java/com/mysema/query/collections/AliasTest.java b/querydsl-collections/src/test/java/com/mysema/query/collections/AliasTest.java
index ad71aa948..cc29e4104 100644
--- a/querydsl-collections/src/test/java/com/mysema/query/collections/AliasTest.java
+++ b/querydsl-collections/src/test/java/com/mysema/query/collections/AliasTest.java
@@ -151,7 +151,7 @@ public class AliasTest extends AbstractQueryTest{
             from(cat,cats).where(cat.mate.alive).list(cat);
             fail("expected RuntimeException");
         }catch(RuntimeException e){
-            assertEquals("null path in expression", e.getMessage());
+            assertEquals("null in cat.mate.alive", e.getMessage());
         }
         
         // 12