api

src/main/java/ru/olegcherednik/json/impl/JacksonFactory.java

@@ -70,8 +70,11 @@ private static ObjectMapper config(ObjectMapper mapper, JsonSettings settings) {
             mapper.setTimeZone(TimeZone.getTimeZone(settings.getZoneId()));
 
         mapper.getSerializerProvider().setNullKeySerializer(JacksonNullKeySerializer.INSTANCE);
-        mapper.configOverride(Map.class).setInclude(JsonInclude.Value.construct(JsonInclude.Include.NON_NULL,
-                                                                                JsonInclude.Include.ALWAYS));
+
+        JsonInclude.Include contentIncl = settings.isSerializeNullMapValue() ? JsonInclude.Include.ALWAYS
+                                                                             : JsonInclude.Include.NON_NULL;
+        mapper.configOverride(Map.class)
+              .setInclude(JsonInclude.Value.construct(JsonInclude.Include.NON_NULL, contentIncl));
 
         return mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.NONE)
                      .setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY)

src/main/java/ru/olegcherednik/json/jackson/enumid/EnumIdKeySerializer.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright Oleg Cherednik
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package ru.olegcherednik.json.jackson.enumid;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import ru.olegcherednik.json.api.enumid.EnumId;
+
+import java.io.IOException;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+final class EnumIdKeySerializer extends JsonSerializer<EnumId> {
+
+    public static final EnumIdKeySerializer INSTANCE = new EnumIdKeySerializer();
+
+    @Override
+    public void serialize(EnumId enumId, JsonGenerator generator, SerializerProvider serializers) throws IOException {
+        generator.writeFieldName(enumId.getId());
+    }
+
+}

src/main/java/ru/olegcherednik/json/jackson/enumid/EnumIdModule.java

@@ -25,6 +25,7 @@ public final class EnumIdModule extends SimpleModule {
 
     public EnumIdModule() {
         addSerializer(EnumId.class, EnumIdSerializer.INSTANCE);
+        addKeySerializer(EnumId.class, EnumIdKeySerializer.INSTANCE);
         _deserializers = EnumIdDeserializers.INSTANCE;
     }
 

src/test/java/ru/olegcherednik/json/jackson/MapNullKeyValueTest.java

@@ -16,8 +16,13 @@
 
 package ru.olegcherednik.json.jackson;
 
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
 import org.testng.annotations.Test;
 import ru.olegcherednik.json.api.Json;
+import ru.olegcherednik.json.api.JsonSettings;
+import ru.olegcherednik.json.api.enumid.EnumId;
 
 import java.util.Map;
 
@@ -30,16 +35,60 @@
 @Test
 public class MapNullKeyValueTest {
 
+    private static final String ONE = "one";
+
     public void shouldSerializeNulWhenWriteMap() {
-        Map<String, String> expected = MapUtils.of("one", "1",
+        Map<String, String> expected = MapUtils.of(ONE, "1",
                                                    "two", null);
         String json = Json.writeValue(expected);
         assertThat(json).isNotNull();
-        assertThat(json).isEqualTo("{\"one\":\"1\",\"two\":null}");
+        assertThat(json).isEqualTo("{\"" + ONE + "\":\"1\",\"two\":null}");
+
+        Map<String, String> actual = Json.readMap(json, String.class, String.class);
+        assertThat(actual).isEqualTo(expected);
+    }
+
+    public void shouldNotSerializeNulWhenWriteMapWithCustomSetting() {
+        JsonSettings settings = JsonSettings.builder()
+                                            .serializeNullMapValue(false)
+                                            .build();
+
+        Map<String, String> expected = MapUtils.of(ONE, "1",
+                                                   "two", null);
+        String json = Json.createWriter(settings).writeValue(expected);
+        assertThat(json).isNotNull();
+        assertThat(json).isEqualTo("{\"" + ONE + "\":\"1\"}");
 
         Map<String, String> actual = Json.readMap(json, String.class, String.class);
+        assertThat(actual).containsOnlyKeys(ONE)
+                          .containsEntry(ONE, "1");
+    }
+
+    public void shouldSerializeNulWhenWriteMapWithEnumKey() {
+        Map<Auto, String> expected = MapUtils.of(Auto.AUDI, "RS3",
+                                                 Auto.MERCEDES, "G64",
+                                                 Auto.BMW, null);
+        String json = Json.writeValue(expected);
+        assertThat(json).isNotNull();
+        assertThat(json).isEqualTo("{\"audi\":\"RS3\",\"mercedes\":\"G64\",\"bmw\":null}");
+
+        Map<Auto, String> actual = Json.readMap(json, Auto.class, String.class);
         assertThat(actual).isEqualTo(expected);
+    }
+
+    @Getter
+    @RequiredArgsConstructor(access = AccessLevel.PACKAGE)
+    public enum Auto implements EnumId {
+
+        AUDI("audi"),
+        BMW("bmw"),
+        MERCEDES("mercedes");
+
+        private final String id;
 
+        public static Auto parseId(String id) {
+            return EnumId.parseId(Auto.class, id);
+        }
     }
 
 }