Extra Pojo with nulls values in collections and maps fixes

JAVA-2756

Author: rozza

bson/src/main/org/bson/codecs/pojo/CollectionPropertyCodecProvider.java

@@ -67,7 +67,12 @@ public Collection<T> decode(final BsonReader reader, final DecoderContext contex
             Collection<T> collection = getInstance();
             reader.readStartArray();
             while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
-                collection.add(codec.decode(reader, context));
+                if (reader.getCurrentBsonType() == BsonType.NULL) {
+                    collection.add(null);
+                    reader.readNull();
+                } else {
+                    collection.add(codec.decode(reader, context));
+                }
             }
             reader.readEndArray();
             return collection;

bson/src/main/org/bson/codecs/pojo/MapPropertyCodecProvider.java

@@ -59,7 +59,11 @@ public void encode(final BsonWriter writer, final Map<String, T> map, final Enco
             writer.writeStartDocument();
             for (final Entry<String, T> entry : map.entrySet()) {
                 writer.writeName(entry.getKey());
-                codec.encode(writer, entry.getValue(), encoderContext);
+                if (entry.getValue() == null) {
+                    writer.writeNull();
+                } else {
+                    codec.encode(writer, entry.getValue(), encoderContext);
+                }
             }
             writer.writeEndDocument();
         }
@@ -69,7 +73,12 @@ public Map<String, T> decode(final BsonReader reader, final DecoderContext conte
             reader.readStartDocument();
             Map<String, T> map = getInstance();
             while (reader.readBsonType() != BsonType.END_OF_DOCUMENT) {
-                map.put(reader.readName(), codec.decode(reader, context));
+                if (reader.getCurrentBsonType() == BsonType.NULL) {
+                    map.put(reader.readName(), null);
+                    reader.readNull();
+                } else {
+                    map.put(reader.readName(), codec.decode(reader, context));
+                }
             }
             reader.readEndDocument();
             return map;

bson/src/test/unit/org/bson/codecs/pojo/PojoRoundTripTest.java

@@ -163,6 +163,10 @@ private static List<TestData> testCases() {
                 "{'collection': [1, 2, 3], 'list': [4, 5, 6], 'linked': [7, 8, 9], 'map': {'A': 1.1, 'B': 2.2, 'C': 3.3},"
                         + "'concurrent': {'D': 4.4, 'E': 5.5, 'F': 6.6}}"));
 
+        data.add(new TestData("Handling of nulls inside collections", getConcreteCollectionsModelWithNulls(),
+                getPojoCodecProviderBuilder(ConcreteCollectionsModel.class),
+                "{'collection': [1, null, 3], 'list': [4, null, 6], 'linked': [null, 8, 9], 'map': {'A': 1.1, 'B': null, 'C': 3.3}}"));
+
         data.add(new TestData("Concrete specific return collection type model through BsonCreator",
                 new CollectionSpecificReturnTypeCreatorModel(Arrays.asList("foo", "bar")),
                 getPojoCodecProviderBuilder(CollectionSpecificReturnTypeCreatorModel.class),

bson/src/test/unit/org/bson/codecs/pojo/PojoTestCase.java

@@ -217,6 +217,19 @@ static ConcreteCollectionsModel getConcreteCollectionsModel() {
         return new ConcreteCollectionsModel(collection, list, linked, map, concurrent);
     }
 
+
+    static ConcreteCollectionsModel getConcreteCollectionsModelWithNulls() {
+        Collection<Integer> collection = asList(1, null, 3);
+        List<Integer> list = asList(4, null, 6);
+        LinkedList<Integer> linked = new LinkedList<Integer>(asList(null, 8, 9));
+        Map<String, Double> map = new HashMap<String, Double>();
+        map.put("A", 1.1);
+        map.put("B", null);
+        map.put("C", 3.3);
+
+        return new ConcreteCollectionsModel(collection, list, linked, map, null);
+    }
+
     static SimpleNestedPojoModel getSimpleNestedPojoModel() {
         SimpleModel simpleModel = getSimpleModel();
         return new SimpleNestedPojoModel(simpleModel);