Generate jackson type id resolver

docs/codegen-options.md

@@ -18,6 +18,7 @@
 | `generateImmutableModels`                             | Boolean                                                               | False                                                  | Specifies whether generated model classes should be immutable. |
 | `generateToString`                                    | Boolean                                                               | False                                                  | Specifies whether generated model classes should have toString method defined. |
 | `addGeneratedAnnotation`                              | Boolean                                                               | True                                                   | Specifies whether generated classes should have `@Generated` annotation. |
+| `generateJacksonTypeIdResolver`                       | Boolean                                                               | False                                                  | Specifies whether generated union interfaces should be annotated with a custom Jackson type id resolver generated in model package. |
 | `apiNamePrefix`                                       | String                                                                | Empty                                                  | Sets the prefix for GraphQL api classes (query, mutation, subscription). |
 | `apiNameSuffix`                                       | String                                                                | `Resolver`                                             | Sets the suffix for GraphQL api classes (query, mutation, subscription). |
 | `apiInterfaceStrategy`                                | *See<br>[ApiInterfaceStrategy](#option-apiinterfacestrategy)*         | `INTERFACE_PER_OPERATION`                              | *See [ApiInterfaceStrategy](#option-apiinterfacestrategy)* |

plugins/gradle/graphql-java-codegen-gradle-plugin/src/main/java/io/github/kobylynskyi/graphql/codegen/gradle/GraphQLCodegenGradleTask.java

@@ -83,6 +83,7 @@ public class GraphQLCodegenGradleTask extends DefaultTask implements GraphQLCode
     private Boolean useOptionalForNullableReturnTypes = MappingConfigConstants.DEFAULT_USE_OPTIONAL_FOR_NULLABLE_RETURN_TYPES;
     private Boolean generateApisWithThrowsException = MappingConfigConstants.DEFAULT_GENERATE_APIS_WITH_THROWS_EXCEPTION;
     private Boolean addGeneratedAnnotation = MappingConfigConstants.DEFAULT_ADD_GENERATED_ANNOTATION;
+    private Boolean generateJacksonTypeIdResolver = MappingConfigConstants.DEFAULT_GENERATE_JACKSON_TYPE_ID_RESOLVER;
     private Set<String> fieldsWithResolvers = new HashSet<>();
     private Set<String> fieldsWithoutResolvers = new HashSet<>();
     private Set<String> typesAsInterfaces = new HashSet<>();
@@ -143,6 +144,7 @@ public void generate() throws Exception {
         mappingConfig.setUseOptionalForNullableReturnTypes(useOptionalForNullableReturnTypes);
         mappingConfig.setGenerateApisWithThrowsException(generateApisWithThrowsException);
         mappingConfig.setAddGeneratedAnnotation(addGeneratedAnnotation);
+        mappingConfig.setGenerateJacksonTypeIdResolver(generateJacksonTypeIdResolver);
         mappingConfig.setApiReturnType(apiReturnType);
         mappingConfig.setApiReturnListType(apiReturnListType);
         mappingConfig.setSubscriptionReturnType(subscriptionReturnType);
@@ -632,6 +634,17 @@ public void setAddGeneratedAnnotation(Boolean addGeneratedAnnotation) {
         this.addGeneratedAnnotation = addGeneratedAnnotation;
     }
 
+    @Input
+    @Optional
+    @Override
+    public Boolean getGenerateJacksonTypeIdResolver() {
+        return generateJacksonTypeIdResolver;
+    }
+
+    public void setGenerateJacksonTypeIdResolver(Boolean generateJacksonTypeIdResolver) {
+        this.generateJacksonTypeIdResolver = generateJacksonTypeIdResolver;
+    }
+
     @Input
     @Optional
     @Override

plugins/maven/graphql-java-codegen-maven-plugin/src/main/java/io/github/kobylynskyi/graphql/codegen/GraphQLCodegenMojo.java

@@ -152,6 +152,9 @@ public class GraphQLCodegenMojo extends AbstractMojo implements GraphQLCodegenCo
     @Parameter(defaultValue = MappingConfigConstants.DEFAULT_ADD_GENERATED_ANNOTATION_STRING)
     private boolean addGeneratedAnnotation;
 
+    @Parameter(defaultValue = MappingConfigConstants.DEFAULT_GENERATE_JACKSON_TYPE_ID_RESOLVER_STRING)
+    private boolean generateJacksonTypeIdResolver;
+
     @Parameter
     private String[] fieldsWithResolvers;
 
@@ -239,6 +242,7 @@ public void execute() throws MojoExecutionException {
         mappingConfig.setUseOptionalForNullableReturnTypes(useOptionalForNullableReturnTypes);
         mappingConfig.setGenerateApisWithThrowsException(generateApisWithThrowsException);
         mappingConfig.setAddGeneratedAnnotation(addGeneratedAnnotation);
+        mappingConfig.setGenerateJacksonTypeIdResolver(generateJacksonTypeIdResolver);
         mappingConfig.setFieldsWithResolvers(mapToHashSet(fieldsWithResolvers));
         mappingConfig.setFieldsWithoutResolvers(mapToHashSet(fieldsWithoutResolvers));
         mappingConfig.setRelayConfig(relayConfig);
@@ -490,6 +494,11 @@ public Boolean getAddGeneratedAnnotation() {
         return addGeneratedAnnotation;
     }
 
+    @Override
+    public Boolean getGenerateJacksonTypeIdResolver() {
+        return generateJacksonTypeIdResolver;
+    }
+
     @Override
     public ApiRootInterfaceStrategy getApiRootInterfaceStrategy() {
         return apiRootInterfaceStrategy;

src/main/java/com/kobylynskyi/graphql/codegen/FreeMarkerTemplateType.java

@@ -10,6 +10,7 @@ enum FreeMarkerTemplateType {
     INTERFACE,
     OPERATIONS,
     PARAMETRIZED_INPUT,
-    RESPONSE_PROJECTION;
+    RESPONSE_PROJECTION,
+    JACKSON_TYPE_ID_RESOLVER;
 
 }

src/main/java/com/kobylynskyi/graphql/codegen/FreeMarkerTemplatesRegistry.java

@@ -13,6 +13,7 @@
 
 import static com.kobylynskyi.graphql.codegen.FreeMarkerTemplateType.ENUM;
 import static com.kobylynskyi.graphql.codegen.FreeMarkerTemplateType.INTERFACE;
+import static com.kobylynskyi.graphql.codegen.FreeMarkerTemplateType.JACKSON_TYPE_ID_RESOLVER;
 import static com.kobylynskyi.graphql.codegen.FreeMarkerTemplateType.OPERATIONS;
 import static com.kobylynskyi.graphql.codegen.FreeMarkerTemplateType.PARAMETRIZED_INPUT;
 import static com.kobylynskyi.graphql.codegen.FreeMarkerTemplateType.REQUEST;
@@ -58,6 +59,8 @@ class FreeMarkerTemplatesRegistry {
                     configuration.getTemplate("templates/java-lang/javaClassGraphqlParametrizedInput.ftl"));
             javaTemplates.put(RESPONSE_PROJECTION,
                     configuration.getTemplate("templates/java-lang/javaClassGraphqlResponseProjection.ftl"));
+            javaTemplates.put(JACKSON_TYPE_ID_RESOLVER,
+                    configuration.getTemplate("templates/java-lang/javaClassGraphqlJacksonTypeIdResolver.ftl"));
             templateMap.put(GeneratedLanguage.JAVA, javaTemplates);
 
             EnumMap<FreeMarkerTemplateType, Template> scalaTemplates = new EnumMap<>(FreeMarkerTemplateType.class);

src/main/java/com/kobylynskyi/graphql/codegen/GraphQLCodegen.java

@@ -1,5 +1,6 @@
 package com.kobylynskyi.graphql.codegen;
 
+import com.kobylynskyi.graphql.codegen.mapper.DataModelMapper;
 import com.kobylynskyi.graphql.codegen.mapper.DataModelMapperFactory;
 import com.kobylynskyi.graphql.codegen.mapper.FieldDefinitionToParameterMapper;
 import com.kobylynskyi.graphql.codegen.model.ApiInterfaceStrategy;
@@ -28,10 +29,17 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 
+import static com.kobylynskyi.graphql.codegen.model.DataModelFields.CLASS_NAME;
+import static com.kobylynskyi.graphql.codegen.model.DataModelFields.GENERATED_ANNOTATION;
+import static com.kobylynskyi.graphql.codegen.model.DataModelFields.GENERATED_INFO;
+import static com.kobylynskyi.graphql.codegen.model.DataModelFields.MODEL_NAME_PREFIX;
+import static com.kobylynskyi.graphql.codegen.model.DataModelFields.MODEL_NAME_SUFFIX;
+import static com.kobylynskyi.graphql.codegen.model.DataModelFields.PACKAGE;
 import static java.util.stream.Collectors.toList;
 
 /**
@@ -185,6 +193,10 @@ protected void initDefaultValues(MappingConfig mappingConfig) {
         if (mappingConfig.getAddGeneratedAnnotation() == null) {
             mappingConfig.setAddGeneratedAnnotation(MappingConfigConstants.DEFAULT_ADD_GENERATED_ANNOTATION);
         }
+        if (mappingConfig.getGenerateJacksonTypeIdResolver() == null) {
+            mappingConfig.setGenerateJacksonTypeIdResolver(
+                    MappingConfigConstants.DEFAULT_GENERATE_JACKSON_TYPE_ID_RESOLVER);
+        }
         if (mappingConfig.getUseOptionalForNullableReturnTypes() == null) {
             mappingConfig.setUseOptionalForNullableReturnTypes(
                     MappingConfigConstants.DEFAULT_USE_OPTIONAL_FOR_NULLABLE_RETURN_TYPES);
@@ -310,6 +322,9 @@ private List<File> processDefinitions(ExtendedDocument document) {
         for (ExtendedInterfaceTypeDefinition definition : document.getInterfaceDefinitions()) {
             generateFieldResolver(context, definition.getFieldDefinitions(), definition).ifPresent(generatedFiles::add);
         }
+        if (Boolean.TRUE.equals(mappingConfig.getGenerateJacksonTypeIdResolver())) {
+            generatedFiles.add(generateJacksonTypeIdResolver(context));
+        }
         System.out.printf("Generated %d definition classes in folder %s%n", generatedFiles.size(),
                 outputDir.getAbsolutePath());
         return generatedFiles;
@@ -531,6 +546,18 @@ private File generateEnum(MappingContext mappingContext, ExtendedEnumTypeDefinit
                 .generateFile(mappingContext, FreeMarkerTemplateType.ENUM, dataModel, outputDir);
     }
 
+    private File generateJacksonTypeIdResolver(MappingContext context) {
+        Map<String, Object> dataModel = new HashMap<>();
+        dataModel.put(PACKAGE, DataModelMapper.getModelPackageName(context));
+        dataModel.put(MODEL_NAME_PREFIX, context.getModelNamePrefix());
+        dataModel.put(MODEL_NAME_SUFFIX, context.getModelNameSuffix());
+        dataModel.put(CLASS_NAME, "GraphqlJacksonTypeIdResolver");
+        dataModel.put(GENERATED_ANNOTATION, context.getAddGeneratedAnnotation());
+        dataModel.put(GENERATED_INFO, context.getGeneratedInformation());
+        return GraphQLCodegenFileCreator
+                .generateFile(context, FreeMarkerTemplateType.JACKSON_TYPE_ID_RESOLVER, dataModel, outputDir);
+    }
+
     protected void initCustomTypeMappings(Collection<ExtendedScalarTypeDefinition> scalarTypeDefinitions) {
         for (ExtendedScalarTypeDefinition definition : scalarTypeDefinitions) {
             if (definition.getDefinition() != null) {

src/main/java/com/kobylynskyi/graphql/codegen/mapper/GraphQLTypeMapper.java

@@ -5,6 +5,7 @@
 import com.kobylynskyi.graphql.codegen.model.MultiLanguageDeprecated;
 import com.kobylynskyi.graphql.codegen.model.NamedDefinition;
 import com.kobylynskyi.graphql.codegen.model.definitions.ExtendedDefinition;
+import com.kobylynskyi.graphql.codegen.model.definitions.ExtendedUnionTypeDefinition;
 import com.kobylynskyi.graphql.codegen.utils.Utils;
 import graphql.language.Argument;
 import graphql.language.Directive;
@@ -262,18 +263,18 @@ default List<String> getAnnotations(MappingContext mappingContext, Type<?> type,
             return getAnnotations(mappingContext, ((NonNullType) type).getType(), def, parentTypeName, true);
         } else if (type instanceof TypeName) {
             return getAnnotations(mappingContext, ((TypeName) type).getName(), def.getName(), parentTypeName,
-                    getDirectives(def), mandatory);
+                    getDirectives(def), mandatory, false);
         }
         return Collections.emptyList();
     }
 
     default List<String> getAnnotations(MappingContext mappingContext, ExtendedDefinition<?, ?> extendedDefinition) {
         return getAnnotations(mappingContext, extendedDefinition.getName(), extendedDefinition.getName(), null,
-                Collections.emptyList(), false);
+                Collections.emptyList(), false, extendedDefinition instanceof ExtendedUnionTypeDefinition);
     }
 
     default List<String> getAnnotations(MappingContext mappingContext, String name) {
-        return getAnnotations(mappingContext, name, name, null, Collections.emptyList(), false);
+        return getAnnotations(mappingContext, name, name, null, Collections.emptyList(), false, false);
     }
 
     /**
@@ -288,7 +289,8 @@ default List<String> getAnnotations(MappingContext mappingContext, String name)
      * @return list of Java annotations for a given GraphQL type
      */
     default List<String> getAnnotations(MappingContext mappingContext, String graphQLTypeName, String name,
-                                        String parentTypeName, List<Directive> directives, boolean mandatory) {
+                                        String parentTypeName, List<Directive> directives, boolean mandatory,
+                                        boolean isUnion) {
         List<String> annotations = new ArrayList<>();
         if (mandatory) {
             String possiblyPrimitiveType = mappingContext.getCustomTypesMapping()
@@ -312,6 +314,17 @@ default List<String> getAnnotations(MappingContext mappingContext, String graphQ
             if (!Utils.isEmpty(annotationsToAdd)) {
                 annotations.addAll(annotationsToAdd);
             }
+        } else if (Boolean.TRUE.equals(mappingContext.getGenerateJacksonTypeIdResolver()) && isUnion) {
+            annotations.add("com.fasterxml.jackson.annotation.JsonTypeInfo(use = " +
+                    "com.fasterxml.jackson.annotation.JsonTypeInfo.Id.NAME, property = \"__typename\")");
+            String modelPackageName = DataModelMapper.getModelPackageName(mappingContext);
+            if (modelPackageName == null) {
+                modelPackageName = "";
+            } else if (Utils.isNotBlank(modelPackageName)) {
+                modelPackageName += ".";
+            }
+            annotations.add("com.fasterxml.jackson.databind.annotation.JsonTypeIdResolver(" + modelPackageName +
+                    "GraphqlJacksonTypeIdResolver.class)");
         }
 
         Map<String, List<String>> directiveAnnotationsMapping = mappingContext.getDirectiveAnnotationsMapping();

src/main/java/com/kobylynskyi/graphql/codegen/model/DataModelFields.java

@@ -10,6 +10,8 @@ public final class DataModelFields {
     public static final String PACKAGE = "package";
     public static final String IMPORTS = "imports";
     public static final String CLASS_NAME = "className";
+    public static final String MODEL_NAME_PREFIX = "modelNamePrefix";
+    public static final String MODEL_NAME_SUFFIX = "modelNameSuffix";
     public static final String NAME = "name";
     public static final String FIELDS = "fields";
     public static final String IMPLEMENTS = "implements";

src/main/java/com/kobylynskyi/graphql/codegen/model/GraphQLCodegenConfiguration.java

@@ -259,6 +259,15 @@ public interface GraphQLCodegenConfiguration {
      */
     Boolean getAddGeneratedAnnotation();
 
+    /**
+     * Specifies whether generated union interfaces should be annotated with a Jackson type id resolver generated in
+     * model package.
+     *
+     * @return <b>true</b> if union interfaces should be annotated with a Jackson type id resolver generated in model
+     * package
+     */
+    Boolean getGenerateJacksonTypeIdResolver();
+
     /**
      * Relay-related configurations.
      *

src/main/java/com/kobylynskyi/graphql/codegen/model/MappingConfig.java

@@ -53,6 +53,7 @@ public class MappingConfig implements GraphQLCodegenConfiguration, Combinable<Ma
     private Boolean useOptionalForNullableReturnTypes;
     private Boolean generateApisWithThrowsException;
     private Boolean addGeneratedAnnotation;
+    private Boolean generateJacksonTypeIdResolver;
 
     // field resolvers configs:
     private Set<String> fieldsWithResolvers = new HashSet<>();
@@ -150,6 +151,8 @@ public void combine(MappingConfig source) {
                 GraphQLCodegenConfiguration::getGenerateApisWithThrowsException);
         addGeneratedAnnotation = getValueOrDefaultToThis(source,
                 GraphQLCodegenConfiguration::getAddGeneratedAnnotation);
+        generateJacksonTypeIdResolver = getValueOrDefaultToThis(source,
+                GraphQLCodegenConfiguration::getGenerateJacksonTypeIdResolver);
         relayConfig = getValueOrDefaultToThis(source, GraphQLCodegenConfiguration::getRelayConfig);
         queryResolverParentInterface = getValueOrDefaultToThis(source,
                 GraphQLCodegenConfiguration::getQueryResolverParentInterface);
@@ -461,6 +464,15 @@ public void setAddGeneratedAnnotation(Boolean addGeneratedAnnotation) {
         this.addGeneratedAnnotation = addGeneratedAnnotation;
     }
 
+    @Override
+    public Boolean getGenerateJacksonTypeIdResolver() {
+        return generateJacksonTypeIdResolver;
+    }
+
+    public void setGenerateJacksonTypeIdResolver(Boolean generateJacksonTypeIdResolver) {
+        this.generateJacksonTypeIdResolver = generateJacksonTypeIdResolver;
+    }
+
     @Override
     public RelayConfig getRelayConfig() {
         return relayConfig;

src/main/java/com/kobylynskyi/graphql/codegen/model/MappingConfigConstants.java

@@ -29,6 +29,8 @@ public class MappingConfigConstants {
     public static final String DEFAULT_GENERATE_APIS_WITH_THROWS_EXCEPTION_STRING = "true";
     public static final boolean DEFAULT_ADD_GENERATED_ANNOTATION = true;
     public static final String DEFAULT_ADD_GENERATED_ANNOTATION_STRING = "true";
+    public static final boolean DEFAULT_GENERATE_JACKSON_TYPE_ID_RESOLVER = false;
+    public static final String DEFAULT_GENERATE_JACKSON_TYPE_ID_RESOLVER_STRING = "false";
     public static final boolean DEFAULT_USE_OPTIONAL_FOR_NULLABLE_RETURN_TYPES = false;
     public static final String DEFAULT_USE_OPTIONAL_FOR_NULLABLE_RETURN_TYPES_STRING = "false";
     public static final ApiNamePrefixStrategy DEFAULT_API_NAME_PREFIX_STRATEGY = ApiNamePrefixStrategy.CONSTANT;

src/main/java/com/kobylynskyi/graphql/codegen/model/MappingContext.java

@@ -202,6 +202,11 @@ public Boolean getAddGeneratedAnnotation() {
         return config.getAddGeneratedAnnotation();
     }
 
+    @Override
+    public Boolean getGenerateJacksonTypeIdResolver() {
+        return config.getGenerateJacksonTypeIdResolver();
+    }
+
     @Override
     public RelayConfig getRelayConfig() {
         return config.getRelayConfig();

src/main/resources/templates/java-lang/javaClassGraphqlJacksonTypeIdResolver.ftl

@@ -0,0 +1,55 @@
+<#if package?has_content>
+package ${package};
+
+</#if>
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.DatabindContext;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.jsontype.impl.TypeIdResolverBase;
+
+<#if generatedAnnotation && generatedInfo.getGeneratedType()?has_content>
+@${generatedInfo.getGeneratedType()}(
+    value = "com.kobylynskyi.graphql.codegen.GraphQLCodegen",
+    date = "${generatedInfo.getDateTime()}"
+)
+</#if>
+public class GraphqlJacksonTypeIdResolver extends TypeIdResolverBase {
+
+    private JavaType superType;
+
+    @Override
+    public void init(JavaType baseType) {
+        superType = baseType;
+    }
+
+    @Override
+    public JavaType typeFromId(DatabindContext context, String typename) {
+        try {
+            var clazz = Class.forName(
+                <#if package?has_content>"${package}." +
+                </#if><#if modelNamePrefix?has_content>"${modelNamePrefix}" +
+                </#if>typename<#if modelNamePrefix?has_content> +
+                "${modelNameSuffix}"</#if>
+            );
+            return context.constructSpecializedType(superType, clazz);
+        } catch (ClassNotFoundException e) {
+            System.err.println(e.getMessage());
+            return null;
+        }
+    }
+
+    @Override
+    public JsonTypeInfo.Id getMechanism() {
+        return JsonTypeInfo.Id.NAME;
+    }
+
+    @Override
+    public String idFromValue(Object obj) {
+        return idFromValueAndType(obj, obj.getClass());
+    }
+
+    @Override
+    public String idFromValueAndType(Object obj, Class<?> subType) {
+        return subType.getSimpleName();
+    }
+}