Missing and duplicate results

src/main/java/org/apache/ibatis/executor/resultset/NestedResultSetHandler.java

@@ -17,7 +17,10 @@
 
 import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -42,6 +45,8 @@
 
 public class NestedResultSetHandler extends FastResultSetHandler {
 
+  private List<Tuple> unhandledObjects = new ArrayList<Tuple>();
+  private Set<CacheKey> handledObjects = new HashSet<CacheKey>();
   private final Map<CacheKey, Object> objectCache = new HashMap<CacheKey, Object>();
   private final Map<CacheKey, Object> ancestorCache = new HashMap<CacheKey, Object>();
 
@@ -83,14 +88,35 @@ protected void handleRowValues(ResultSet rs, ResultMap resultMap, ResultHandler
       final CacheKey rowKey = createRowKey(discriminatedResultMap, rs, null, resultColumnCache);
       Object partialObject = objectCache.get(rowKey);
       if (partialObject == null && rowValue != null) { // issue #542 delay calling ResultHandler until object ends
-        if (mappedStatement.isResultOrdered()) objectCache.clear(); // issue #577 clear memory if ordered
+        if (mappedStatement.isResultOrdered()) clearCache(); // issue #577 clear memory if ordered
         callResultHandler(resultHandler, resultContext, rowValue);
       } 
       rowValue = getRowValue(rs, discriminatedResultMap, rowKey, rowKey, null, resultColumnCache, partialObject);
+      if( partialObject == null ) {
+       // issue #542 when results are not ordered (as described in comment #1), need to keep track of what was or wasn't handled
+        unhandledObjects.add(new Tuple(rowKey, rowValue));
+      }
     }
     if (rowValue != null) callResultHandler(resultHandler, resultContext, rowValue);
   }
-
+
+  @Override
+  protected void callResultHandler(ResultHandler resultHandler, DefaultResultContext resultContext, Object rowValueIgnored) {
+    for( Iterator<Tuple> iter = unhandledObjects.iterator(); iter.hasNext(); ) {
+      Tuple tuple = iter.next();
+      if( !handledObjects.contains(tuple.getRowKey()) ) {
+        super.callResultHandler(resultHandler, resultContext, tuple.getRowValue());
+        handledObjects.add(tuple.getRowKey());
+      }
+    }
+    unhandledObjects.clear();
+  }
+
+  private void clearCache() {
+    handledObjects.clear();
+    objectCache.clear();
+  }
+
   //
   // GET VALUE FROM ROW
   //
@@ -324,4 +350,19 @@ private void createRowKeyForMap(ResultSet rs, CacheKey cacheKey, ResultColumnCac
     }
   }
 
+  private static class Tuple {
+    private CacheKey rowKey;
+    private Object rowValue;
+
+    public Tuple(CacheKey rowKey, Object rowValue) {
+      this.rowKey = rowKey;
+      this.rowValue = rowValue;
+    }
+    public CacheKey getRowKey() {
+      return rowKey;
+    }
+    public Object getRowValue() {
+      return rowValue;
+    }
+  }
 }

src/test/java/org/apache/ibatis/submitted/nestedresulthandler/Mapper.java

@@ -19,4 +19,5 @@
 
 public interface Mapper {
   List<Person> getPersons();
+  List<Person> getPersonsWithItemsOrdered();
 }

src/test/java/org/apache/ibatis/submitted/nestedresulthandler/Mapper.xml

@@ -29,8 +29,15 @@
 	</resultMap>
 
 	<select id="getPersons" resultMap="personResult">
-		select p.id as person_id, p.name as person_name, i.id as item_id, i.name as item_name 
-		from persons p, items i 
+		select p.id as person_id, p.name as person_name, i.id as item_id, i.name as item_name
+		from persons p, items i
 		where p.id = i.owner
 	</select>
+
+	<select id="getPersonsWithItemsOrdered" resultMap="personResult">
+		select p.id as person_id, p.name as person_name, i.id as item_id, i.name as item_name
+		from persons p, items i
+		where p.id = i.owner
+		order by i.name
+	</select>
 </mapper>

src/test/java/org/apache/ibatis/submitted/nestedresulthandler/NestedResultHandlerTest.java

@@ -58,7 +58,7 @@ public void testGetPerson() {
       Mapper mapper = sqlSession.getMapper(Mapper.class);
 
       List<Person> persons = mapper.getPersons();
-      
+
       Person person = persons.get(0);
       Assert.assertEquals("grandma", person.getName());
       Assert.assertTrue(person.owns("book"));
@@ -79,7 +79,7 @@ public void testGetPerson() {
       sqlSession.close();
     }
   }
-  
+
   @Test // issue #542
   public void testGetPersonWithHandler() {
     SqlSession sqlSession = sqlSessionFactory.openSession();
@@ -91,10 +91,43 @@ public void handleResult(ResultContext context) {
             Assert.assertEquals(2, person.getItems().size());
           }
         }
-      });      
+      });
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  /**
+   * Fix bug caused by issue #542, see new issue #22 on github
+   * If we order by a nested result map attribute we can miss some records and end up with duplicates instead.
+   */
+  @Test
+  public void testGetPersonOrderedByItem() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      Mapper mapper = sqlSession.getMapper(Mapper.class);
+
+      List<Person> persons = mapper.getPersonsWithItemsOrdered();
+
+      Person person = persons.get(0);
+      Assert.assertEquals("grandma", person.getName());
+      Assert.assertTrue(person.owns("book"));
+      Assert.assertTrue(person.owns("tv"));
+      Assert.assertEquals(2, person.getItems().size());
+
+      person = persons.get(1);
+      Assert.assertEquals("brother", person.getName());
+      Assert.assertTrue(person.owns("car"));
+      Assert.assertEquals(1, person.getItems().size());
+
+      person = persons.get(2);
+      Assert.assertEquals("sister", person.getName());
+      Assert.assertTrue(person.owns("phone"));
+      Assert.assertTrue(person.owns("shoes"));
+      Assert.assertEquals(2, person.getItems().size());
     } finally {
       sqlSession.close();
     }
   }
-  
+
 }