[Java][client] make it possible to send explicit nulls for nullable fields

modules/openapi-generator-maven-plugin/examples/java-client.xml

@@ -120,7 +120,12 @@
           <groupId>com.fasterxml.jackson.jaxrs</groupId>
           <artifactId>jackson-jaxrs-json-provider</artifactId>
           <version>${jackson-version}</version>
-        </dependency>
+      </dependency>
+      <dependency>
+          <groupId>org.openapitools</groupId>
+          <artifactId>jackson-databind-nullable</artifactId>
+          <version>${jackson-databind-nullable-version}</version>
+      </dependency>
 
         <!-- Joda time: if you use it -->
         <dependency>
@@ -146,6 +151,7 @@
         <swagger-annotations-version>1.5.8</swagger-annotations-version>
         <jersey-version>2.27</jersey-version>
         <jackson-version>2.8.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jodatime-version>2.7</jodatime-version>
         <maven-plugin-version>1.0.0</maven-plugin-version>
         <junit-version>4.8.1</junit-version>

modules/openapi-generator-maven-plugin/examples/multi-module/java-client/pom.xml

@@ -133,7 +133,12 @@
           <groupId>com.fasterxml.jackson.jaxrs</groupId>
           <artifactId>jackson-jaxrs-json-provider</artifactId>
           <version>${jackson-version}</version>
-        </dependency>
+      </dependency>
+      <dependency>
+          <groupId>org.openapitools</groupId>
+          <artifactId>jackson-databind-nullable</artifactId>
+          <version>${jackson-databind-nullable-version}</version>
+      </dependency>
 
         <!-- Joda time: if you use it -->
         <dependency>

modules/openapi-generator-maven-plugin/examples/multi-module/pom.xml

@@ -16,6 +16,7 @@
         <swagger-annotations-version>1.5.8</swagger-annotations-version>
         <jersey-version>2.27</jersey-version>
         <jackson-version>2.8.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jodatime-version>2.7</jodatime-version>
         <maven-plugin-version>1.0.0</maven-plugin-version>
         <junit-version>4.8.1</junit-version>

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -417,6 +417,8 @@ public void processOpts() {
         importMapping.put("JsonTypeInfo", "com.fasterxml.jackson.annotation.JsonTypeInfo");
         importMapping.put("JsonCreator", "com.fasterxml.jackson.annotation.JsonCreator");
         importMapping.put("JsonValue", "com.fasterxml.jackson.annotation.JsonValue");
+        importMapping.put("JsonIgnore", "com.fasterxml.jackson.annotation.JsonIgnore");
+        importMapping.put("JsonInclude", "com.fasterxml.jackson.annotation.JsonInclude");
         importMapping.put("SerializedName", "com.google.gson.annotations.SerializedName");
         importMapping.put("TypeAdapter", "com.google.gson.TypeAdapter");
         importMapping.put("JsonAdapter", "com.google.gson.annotations.JsonAdapter");
@@ -800,7 +802,13 @@ public String toDefaultValue(Schema p) {
                 }
             }
             return null;
+        } else if (ModelUtils.isObjectSchema(p)) {
+            if (p.getDefault() != null) {
+                return super.toDefaultValue(p);
+            }
+            return null;
         }
+
         return super.toDefaultValue(p);
     }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java

@@ -24,6 +24,7 @@
 import org.openapitools.codegen.languages.features.GzipFeatures;
 import org.openapitools.codegen.languages.features.PerformBeanValidationFeatures;
 import org.openapitools.codegen.templating.mustache.CaseFormatLambda;
+import org.openapitools.codegen.utils.ModelUtils;
 import org.openapitools.codegen.utils.ProcessUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -583,6 +584,7 @@ public void postProcessModelProperty(CodegenModel model, CodegenProperty propert
             if (additionalProperties.containsKey("jackson")) {
                 model.imports.add("JsonProperty");
                 model.imports.add("JsonValue");
+                model.imports.add("JsonInclude");
             }
             if (additionalProperties.containsKey("gson")) {
                 model.imports.add("SerializedName");
@@ -623,6 +625,39 @@ public Map<String, Object> postProcessModelsEnum(Map<String, Object> objs) {
         return objs;
     }
 
+    @Override
+    public Map<String, Object> postProcessModels(Map<String, Object> objs) {
+        objs = super.postProcessModels(objs);
+        if (additionalProperties.containsKey("jackson") && !JERSEY1.equals(getLibrary())) {
+            List<Map<String, String>> imports = (List<Map<String, String>>) objs.get("imports");
+            List<Object> models = (List<Object>) objs.get("models");
+            for (Object _mo : models) {
+                Map<String, Object> mo = (Map<String, Object>) _mo;
+                CodegenModel cm = (CodegenModel) mo.get("model");
+                boolean addImports = false;
+                for (CodegenProperty var : cm.vars) {
+                    boolean isOptionalNullable = Boolean.FALSE.equals(var.required) && Boolean.TRUE.equals(var.isNullable);
+                    // only add JsonNullable and related imports to optional and nullable values
+                    addImports |= isOptionalNullable;
+                    var.getVendorExtensions().put("isJacksonOptionalNullable", isOptionalNullable);
+                }
+                if (addImports) {
+                    cm.imports.add("JsonNullable");
+                    Map<String, String> itemJsonNullable = new HashMap<String, String>();
+                    itemJsonNullable.put("import", "org.openapitools.jackson.nullable.JsonNullable");
+                    imports.add(itemJsonNullable);
+
+                    cm.imports.add("NoSuchElementException");
+                    Map<String, String> itemExc = new HashMap<String, String>();
+                    itemExc.put("import", "java.util.NoSuchElementException");
+                    imports.add(itemExc);
+                }
+            }
+        }
+
+        return objs;
+    }
+
     public void setUseRxJava(boolean useRxJava) {
         this.useRxJava = useRxJava;
         doNotUseRx = false;

modules/openapi-generator/src/main/resources/Java/jackson_annotations.mustache

@@ -0,0 +1,19 @@
+{{!
+ If this is map and items are nullable, make sure that nulls are included.
+ To determine what JsonInclude.Include method to use, consider the following:
+ * If the field is required, always include it, even if it is null.
+ * Else use custom behaviour, IOW use whatever is defined on the object mapper
+ }}
+  @JsonProperty(JSON_PROPERTY_{{nameInSnakeCase}})
+  @JsonInclude({{#isMapContainer}}{{#items.isNullable}}content = JsonInclude.Include.ALWAYS, {{/items.isNullable}}{{/isMapContainer}}value = JsonInclude.Include.{{#required}}ALWAYS{{/required}}{{^required}}USE_DEFAULTS{{/required}})
+  {{#withXml}}
+    {{^isContainer}}
+  @JacksonXmlProperty({{#isXmlAttribute}}isAttribute = true, {{/isXmlAttribute}}{{#xmlNamespace}}namespace="{{xmlNamespace}}", {{/xmlNamespace}}localName = "{{#xmlName}}{{xmlName}}{{/xmlName}}{{^xmlName}}{{baseName}}{{/xmlName}}")
+    {{/isContainer}}
+    {{#isContainer}}
+      {{#isXmlWrapped}}
+  // items.xmlName={{items.xmlName}}
+  @JacksonXmlElementWrapper(useWrapping = {{isXmlWrapped}}, {{#xmlNamespace}}namespace="{{xmlNamespace}}", {{/xmlNamespace}}localName = "{{#items.xmlName}}{{items.xmlName}}{{/items.xmlName}}{{^items.xmlName}}{{items.baseName}}{{/items.xmlName}}")
+      {{/isXmlWrapped}}
+    {{/isContainer}}
+  {{/withXml}}

modules/openapi-generator/src/main/resources/Java/libraries/feign/ApiClient.mustache

@@ -12,6 +12,7 @@ import org.threeten.bp.*;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#joda}}
 import com.fasterxml.jackson.datatype.joda.JodaModule;
 {{/joda}}
@@ -177,6 +178,8 @@ public class ApiClient {
     module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
     objectMapper.registerModule(module);
     {{/threetenbp}}
+    JsonNullableModule jnm = new JsonNullableModule();
+    objectMapper.registerModule(jnm);
     return objectMapper;
   }
 

modules/openapi-generator/src/main/resources/Java/libraries/feign/pom.mustache

@@ -244,6 +244,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
             <!-- XML Support -->
@@ -310,6 +315,7 @@
         <feign-version>{{#useFeign10}}10.2.3{{/useFeign10}}{{^useFeign10}}9.7.0{{/useFeign10}}</feign-version>
         <feign-form-version>2.1.0</feign-form-version>
         <jackson-version>2.9.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
         {{#threetenbp}}
         <jackson-threetenbp-version>2.6.4</jackson-threetenbp-version>

modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/ApiClient.mustache

@@ -4,6 +4,7 @@ import {{apiPackage}}.*;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#joda}}
 import com.fasterxml.jackson.datatype.joda.JodaModule;
 {{/joda}}
@@ -53,6 +54,8 @@ public class ApiClient {
         module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
         objectMapper.registerModule(module);
         {{/threetenbp}}
+        JsonNullableModule jnm = new JsonNullableModule();
+        objectMapper.registerModule(jnm);
         return objectMapper;
     }
 

modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/pom.mustache

@@ -253,6 +253,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
             <!-- XML processing: Jackson -->
             <dependency>
@@ -303,6 +308,7 @@
         <jersey-common-version>2.25.1</jersey-common-version>
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         {{#joda}}
         <jodatime-version>2.9.9</jodatime-version>
         {{/joda}}

modules/openapi-generator/src/main/resources/Java/libraries/jersey2/JSON.mustache

@@ -5,6 +5,7 @@ import org.threeten.bp.*;
 {{/threetenbp}}
 import com.fasterxml.jackson.annotation.*;
 import com.fasterxml.jackson.databind.*;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#java8}}
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 {{/java8}}
@@ -45,6 +46,8 @@ public class JSON implements ContextResolver<ObjectMapper> {
     module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
     mapper.registerModule(module);
     {{/threetenbp}}
+    JsonNullableModule jnm = new JsonNullableModule();
+    mapper.registerModule(jnm);
   }
 
   /**

modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pom.mustache

@@ -276,6 +276,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
             <!-- XML processing: JAXB -->
@@ -357,6 +362,7 @@
         {{/supportJava6}}
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         {{#threetenbp}}
         <threetenbp-version>2.6.4</threetenbp-version>
         {{/threetenbp}}

modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache

@@ -6,6 +6,7 @@ import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 
 import java.net.URI;
 import java.net.URLEncoder;
@@ -151,6 +152,8 @@ public class ApiClient {
     mapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
     mapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
     mapper.registerModule(new JavaTimeModule());
+    JsonNullableModule jnm = new JsonNullableModule();
+    mapper.registerModule(jnm);
     URI baseURI = URI.create("{{{basePath}}}");
     scheme = baseURI.getScheme();
     host = baseURI.getHost();

modules/openapi-generator/src/main/resources/Java/libraries/native/pom.mustache

@@ -188,6 +188,11 @@
             <artifactId>jackson-datatype-jsr310</artifactId>
             <version>${jackson-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
 
         <!-- @Nullable annotation -->
         <dependency>
@@ -210,6 +215,7 @@
         <maven.compiler.source>11</maven.compiler.source>
         <maven.compiler.target>11</maven.compiler.target>
         <jackson-version>2.9.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <junit-version>4.12</junit-version>
     </properties>
 </project>

modules/openapi-generator/src/main/resources/Java/libraries/resteasy/JSON.mustache

@@ -2,6 +2,7 @@ package {{invokerPackage}};
 
 import com.fasterxml.jackson.annotation.*;
 import com.fasterxml.jackson.databind.*;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#java8}}
 import com.fasterxml.jackson.datatype.jsr310.*;
 {{/java8}}
@@ -26,6 +27,8 @@ public class JSON implements ContextResolver<ObjectMapper> {
     mapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
     mapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
     mapper.setDateFormat(new RFC3339DateFormat());
+    JsonNullableModule jnm = new JsonNullableModule();
+    mapper.registerModule(jnm);
     {{#java8}}
     mapper.registerModule(new JavaTimeModule());
     {{/java8}}

modules/openapi-generator/src/main/resources/Java/libraries/resteasy/pom.mustache

@@ -212,6 +212,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
         <!-- XML processing: Jackson -->
@@ -291,6 +296,7 @@
         <resteasy-version>3.1.3.Final</resteasy-version>
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <threetenbp-version>2.6.4</threetenbp-version>
         {{^java8}}
         <jodatime-version>2.9.9</jodatime-version>

modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/ApiClient.mustache

@@ -39,6 +39,7 @@ import com.fasterxml.jackson.datatype.threetenbp.ThreeTenModule;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{/threetenbp}}
 
 import java.io.BufferedReader;
@@ -661,6 +662,7 @@ public class ApiClient {
         messageConverters.add(new MappingJackson2HttpMessageConverter());
         XmlMapper xmlMapper = new XmlMapper();
         xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true);
+        xmlMapper.registerModule(new JsonNullableModule());
         messageConverters.add(new MappingJackson2XmlHttpMessageConverter(xmlMapper));
 
         RestTemplate restTemplate = new RestTemplate(messageConverters);
@@ -674,6 +676,7 @@ public class ApiClient {
                 module.addDeserializer(OffsetDateTime.class, CustomInstantDeserializer.OFFSET_DATE_TIME);
                 module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
                 mapper.registerModule(module);
+                mapper.registerModule(new JsonNullableModule());
             }
         }
         {{/threetenbp}}

modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/pom.mustache

@@ -255,6 +255,11 @@
             <artifactId>jackson-jaxrs-json-provider</artifactId>
             <version>${jackson-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
             <!-- XML processing: Jackson -->
@@ -306,6 +311,7 @@
         <spring-web-version>4.3.9.RELEASE</spring-web-version>
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         {{#joda}}
         <jodatime-version>2.9.9</jodatime-version>
         {{/joda}}

modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/play24/ApiClient.mustache

@@ -8,6 +8,8 @@ import java.util.*;
 import retrofit2.Retrofit;
 import retrofit2.converter.scalars.ScalarsConverterFactory;
 import retrofit2.converter.jackson.JacksonConverterFactory;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 
 import play.libs.Json;
 import play.libs.ws.WSClient;
@@ -68,10 +70,14 @@ public class ApiClient {
             auth.applyToParams(extraQueryParams, extraHeaders);
         }
 
+        ObjectMapper mapper = Json.mapper();
+        JsonNullableModule jnm = new JsonNullableModule();
+        mapper.registerModule(jnm);
+
         return new Retrofit.Builder()
                        .baseUrl(basePath)
                        .addConverterFactory(ScalarsConverterFactory.create())
-                       .addConverterFactory(JacksonConverterFactory.create(Json.mapper()))
+                       .addConverterFactory(JacksonConverterFactory.create(mapper))
                        .callFactory(new Play24CallFactory(wsClient, extraHeaders, extraQueryParams))
                        .addCallAdapterFactory(new Play24CallAdapterFactory())
                        .build()