querydsl-collections/src/main/java/com/mysema/query/collections/DefaultQueryEngine.java

@@ -46,8 +46,8 @@ public class DefaultQueryEngine implements QueryEngine {
     
     private List<?> distinct(List<?> list) {
         if (!list.isEmpty() && list.get(0).getClass().isArray()){
-            Set set = new HashSet();
-            List rv = new ArrayList();
+            Set set = new HashSet(list.size());
+            List rv = new ArrayList(list.size());
             for (Object o : list){
                 if (set.add(Arrays.asList((Object[])o))){
                     rv.add(o);
@@ -59,17 +59,7 @@ public class DefaultQueryEngine implements QueryEngine {
         }
     }
 
-    private List evaluateMultipleSources(QueryMetadata metadata, Map<Expr<?>, Iterable<?>> iterables, boolean count) {
-        List<Expr<?>> sources = new ArrayList<Expr<?>>();
-        for (JoinExpression join : metadata.getJoins()){
-            if (join.getType() == JoinType.DEFAULT){
-                sources.add(join.getTarget());    
-            }else{
-                Operation target = (Operation) join.getTarget();
-               sources.add(target.getArg(1));
-            }            
-        }
-        
+    private List evaluateMultipleSources(QueryMetadata metadata, Map<Expr<?>, Iterable<?>> iterables, boolean count) {        
         // from where
         Evaluator<List<Object[]>> ev = evaluatorFactory.createEvaluator(metadata.getJoins(), metadata.getWhere());
         List<Iterable<?>> iterableList = new ArrayList<Iterable<?>>(metadata.getJoins().size());
@@ -80,7 +70,17 @@ public class DefaultQueryEngine implements QueryEngine {
         }
         List<?> list = ev.evaluate(iterableList.toArray());
         
-        if (!count && !list.isEmpty()){            
+        if (!count && !list.isEmpty()){
+            List<Expr<?>> sources = new ArrayList<Expr<?>>();
+            for (JoinExpression join : metadata.getJoins()){
+                if (join.getType() == JoinType.DEFAULT){
+                    sources.add(join.getTarget());    
+                }else{
+                    Operation target = (Operation) join.getTarget();
+                   sources.add(target.getArg(1));
+                }            
+            }
+            
             // ordered
             if (!metadata.getOrderBy().isEmpty()){
                 order(metadata, sources, list);
@@ -91,6 +91,10 @@ public class DefaultQueryEngine implements QueryEngine {
                 list = metadata.getModifiers().subList(list);
             }
             
+            if (list.isEmpty()){
+                return list;
+            }
+            
             // projection
             list = project(metadata, sources, list);                
         }
@@ -106,6 +110,7 @@ public class DefaultQueryEngine implements QueryEngine {
 
     private List evaluateSingleSource(QueryMetadata metadata, Map<Expr<?>, Iterable<?>> iterables, boolean count) {        
         Expr<?> source = metadata.getJoins().get(0).getTarget();
+        List<Expr<?>> sources = Collections.<Expr<?>>singletonList(source);
         Iterable<?> iterable = iterables.values().iterator().next(); 
         List<?> list;
         if (iterable instanceof List){
@@ -120,13 +125,14 @@ public class DefaultQueryEngine implements QueryEngine {
             list = evaluator.evaluate(list);
         }        
         
-        if (!count && !list.isEmpty()){
-            // clone list
-            list = new ArrayList(list);
-            
+        if (!count && !list.isEmpty()){            
             // ordered
             if (!metadata.getOrderBy().isEmpty()){
-                order(metadata, Collections.<Expr<?>>singletonList(source), list);
+                // clone list
+                if (list == iterable){
+                    list = new ArrayList(list);    
+                }
+                order(metadata, sources, list);
             }        
             
             // limit + offset
@@ -134,13 +140,16 @@ public class DefaultQueryEngine implements QueryEngine {
                 list = metadata.getModifiers().subList(list);
             }
             
+            if (list.isEmpty()){
+                return list;
+            }
+            
             // projection
             if (metadata.getProjection().size() > 1 || !metadata.getProjection().get(0).equals(source)){
-                list = project(metadata, Collections.<Expr<?>>singletonList(source), list);
+                list = project(metadata, sources, list);
             }            
         
-        }
-        
+        }        
 
         // distinct
         if (metadata.isDistinct()){            

querydsl-collections/src/main/java/com/mysema/query/collections/MiniApi.java

@@ -24,20 +24,16 @@ public final class MiniApi {
     }
     
     public static <A> ColQuery from(A alias, Iterable<A> col) {
-        return query().from(Alias.$(alias), col);
+        return new ColQueryImpl().from(Alias.$(alias), col);
     }
     
     public static <A> ColQuery from(Path<A> path, A... arr) {
-        return query().from(path, Arrays.asList(arr));
+        return new ColQueryImpl().from(path, Arrays.asList(arr));
     }
     
     public static <A> ColQuery from(Path<A> path, Iterable<A> col) {
-        return query().from(path, col);
-    }
-    
-    private static ColQuery query(){
-        return new ColQueryImpl();
-    }
+        return new ColQueryImpl().from(path, col);
+    }    
 
     public static <A> ColUpdateClause<A> update(Path<A> path, Iterable<A> col){
         return new ColUpdateClause<A>(path, col);