DATAMONGO-378 - Fixed potential ClassCastException for MapReduceResults and upcoming MongoDB release.

The type of the value returned for the total field of the timing map in map-reduce results has changed from Integer to Long as of MongoDB version 2.1.0 apparently. Changed MapReduceResults to accommodate either Integer or Long types.

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/mapreduce/MapReduceResults.java

@@ -88,13 +88,25 @@ public class MapReduceResults<T> implements Iterable<T> {
 		}
 
 		if (timing.get("mapTime") != null && timing.get("emitLoop") != null && timing.get("total") != null) {
-			return new MapReduceTiming((Long) timing.get("mapTime"), (Integer) timing.get("emitLoop"),
-					(Integer) timing.get("total"));
+			return new MapReduceTiming(getAsLong(timing, "mapTime"), getAsLong(timing, "emitLoop"),
+					getAsLong(timing, "total"));
 		}
 
 		return new MapReduceTiming(-1, -1, -1);
 	}
 
+	/**
+	 * Returns the value of the source's field with the given key as {@link Long}.
+	 * 
+	 * @param source
+	 * @param key
+	 * @return
+	 */
+	private Long getAsLong(DBObject source, String key) {
+		Object raw = source.get(key);
+		return raw instanceof Long ? (Long) raw : (Integer) raw;
+	}
+
 	/**
 	 * Parses the raw {@link DBObject} result into a {@link MapReduceCounts} value object.
 	 * 

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/mapreduce/MapReduceResultsUnitTests.java

@@ -56,4 +56,17 @@ public class MapReduceResultsUnitTests {
 		assertThat(results.getOutputCollection(), is("FOO"));
 	}
 
+	/**
+	 * @see DATAMONGO-378
+	 */
+	@Test
+	public void handlesLongTotalInResult() {
+
+		DBObject inner = new BasicDBObject("total", 1L);
+		inner.put("mapTime", 1L);
+		inner.put("emitLoop", 1);
+
+		DBObject source = new BasicDBObject("timing", inner);
+		new MapReduceResults<Object>(Collections.emptyList(), source);
+	}
 }