feat(#389): allow templating for generated Java / Kotlin class names

Adds an optional `nameTemplate` input parameter to the plugin, allowing
customization of the generated Java / Kotlin class names.

The following template variables are supported:
- name - the original name of the class
- schemaType - the GraphQL schema type (Type, Input, Interface, Enum)

The default value for this new property is null. In this case the output
will be identical to the current one.

Examples:

Given an original class name `Person` and schema type `Type`:
 - null -> Person
 - "{name}GraphQL{schemaType}" -> PersonGraphQLType
 - "{name}GraphQL" -> PersonGraphQL
 - "{name}{schemaType}" -> PersonType

Author: BlasiusSecundus

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/CodeGen.kt

@@ -505,7 +505,8 @@ class CodeGenConfig(
     var javaGenerateAllConstructor: Boolean = true,
     var implementSerializable: Boolean = false,
     var addGeneratedAnnotation: Boolean = false,
-    var addDeprecatedAnnotation: Boolean = false
+    var addDeprecatedAnnotation: Boolean = false,
+    var nameTemplate: String? = null
 ) {
     val packageNameClient: String = "$packageName.$subPackageNameClient"
 

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/java/DataTypeGenerator.kt

@@ -18,12 +18,38 @@
 
 package com.netflix.graphql.dgs.codegen.generators.java
 
-import com.netflix.graphql.dgs.codegen.*
+import com.netflix.graphql.dgs.codegen.CodeGenConfig
+import com.netflix.graphql.dgs.codegen.CodeGenResult
+import com.netflix.graphql.dgs.codegen.filterSkipped
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.SiteTarget
 import com.netflix.graphql.dgs.codegen.generators.shared.applyDirectivesJava
-import com.squareup.javapoet.*
-import graphql.language.*
+import com.netflix.graphql.dgs.codegen.shouldSkip
+import com.squareup.javapoet.ClassName
+import com.squareup.javapoet.CodeBlock
+import com.squareup.javapoet.FieldSpec
+import com.squareup.javapoet.JavaFile
+import com.squareup.javapoet.MethodSpec
+import com.squareup.javapoet.ParameterSpec
+import com.squareup.javapoet.TypeSpec
+import graphql.language.ArrayValue
+import graphql.language.BooleanValue
+import graphql.language.Description
+import graphql.language.Directive
+import graphql.language.Document
+import graphql.language.EnumValue
+import graphql.language.FloatValue
+import graphql.language.InputObjectTypeDefinition
+import graphql.language.InputObjectTypeExtensionDefinition
+import graphql.language.IntValue
+import graphql.language.InterfaceTypeDefinition
+import graphql.language.ListType
+import graphql.language.ObjectTypeDefinition
+import graphql.language.ObjectTypeExtensionDefinition
+import graphql.language.StringValue
+import graphql.language.Type
 import graphql.language.TypeName
+import graphql.language.UnionTypeDefinition
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import java.io.Serializable
@@ -39,7 +65,7 @@ class DataTypeGenerator(config: CodeGenConfig, document: Document) : BaseDataTyp
 
         logger.info("Generating data type ${definition.name}")
 
-        val name = definition.name
+        val name = definition.templatedClassName(config.nameTemplate)
         val unionTypes = document.getDefinitionsOfType(UnionTypeDefinition::class.java).filter { union ->
             union.memberTypes.asSequence().map { it as TypeName }.any { it.name == name }
         }.map { it.name }
@@ -120,7 +146,7 @@ class InputTypeGenerator(config: CodeGenConfig, document: Document) : BaseDataTy
 
         logger.info("Generating input type ${definition.name}")
 
-        val name = definition.name
+        val name = definition.templatedClassName(config.nameTemplate)
         val fieldDefinitions = definition.inputValueDefinitions.map {
             val defaultValue = it.defaultValue?.let { defVal ->
                 when (defVal) {

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/java/EnumTypeGenerator.kt

@@ -20,6 +20,7 @@ package com.netflix.graphql.dgs.codegen.generators.java
 
 import com.netflix.graphql.dgs.codegen.CodeGenConfig
 import com.netflix.graphql.dgs.codegen.CodeGenResult
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.SiteTarget
 import com.netflix.graphql.dgs.codegen.generators.shared.applyDirectivesJava
 import com.netflix.graphql.dgs.codegen.shouldSkip
@@ -42,7 +43,7 @@ class EnumTypeGenerator(private val config: CodeGenConfig) {
 
         val javaType =
             TypeSpec
-                .enumBuilder(definition.name)
+                .enumBuilder(definition.templatedClassName(config.nameTemplate))
                 .addModifiers(Modifier.PUBLIC)
                 .addOptionalGeneratedAnnotation(config)
 

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/java/InterfaceGenerator.kt

@@ -22,12 +22,18 @@ import com.netflix.graphql.dgs.codegen.CodeGenConfig
 import com.netflix.graphql.dgs.codegen.CodeGenResult
 import com.netflix.graphql.dgs.codegen.filterSkipped
 import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.capitalized
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.shouldSkip
 import com.squareup.javapoet.ClassName
 import com.squareup.javapoet.JavaFile
 import com.squareup.javapoet.MethodSpec
 import com.squareup.javapoet.TypeSpec
-import graphql.language.*
+import graphql.language.Document
+import graphql.language.FieldDefinition
+import graphql.language.InterfaceTypeDefinition
+import graphql.language.InterfaceTypeExtensionDefinition
+import graphql.language.ObjectTypeDefinition
+import graphql.language.TypeName
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import javax.lang.model.element.Modifier
@@ -48,7 +54,7 @@ class InterfaceGenerator(private val config: CodeGenConfig, private val document
         }
 
         logger.info("Generating type ${definition.name}")
-        val javaType = TypeSpec.interfaceBuilder(definition.name)
+        val javaType = TypeSpec.interfaceBuilder(definition.templatedClassName(config.nameTemplate))
             .addOptionalGeneratedAnnotation(config)
             .addModifiers(Modifier.PUBLIC)
 

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/kotlin/KotlinDataTypeGenerator.kt

@@ -22,6 +22,7 @@ import com.netflix.graphql.dgs.codegen.CodeGenConfig
 import com.netflix.graphql.dgs.codegen.CodeGenResult
 import com.netflix.graphql.dgs.codegen.filterSkipped
 import com.netflix.graphql.dgs.codegen.generators.java.InputTypeGenerator
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.applyDirectivesKotlin
 import com.netflix.graphql.dgs.codegen.shouldSkip
 import com.squareup.kotlinpoet.BOOLEAN
@@ -67,7 +68,7 @@ class KotlinDataTypeGenerator(config: CodeGenConfig, document: Document) :
                 .filterSkipped()
                 .map { Field(it.name, typeUtils.findReturnType(it.type), typeUtils.isNullable(it.type), null, it.description, it.directives) }
         val interfaces = definition.implements
-        return generate(definition.name, fields, interfaces, document, definition.description, definition.directives)
+        return generate(definition.templatedClassName(config.nameTemplate), fields, interfaces, document, definition.description, definition.directives)
     }
 }
 
@@ -94,7 +95,7 @@ class KotlinInputTypeGenerator(config: CodeGenConfig, document: Document) :
                 }
             )
         val interfaces = emptyList<Type<*>>()
-        return generate(definition.name, fields, interfaces, document, definition.description, definition.directives)
+        return generate(definition.templatedClassName(config.nameTemplate), fields, interfaces, document, definition.description, definition.directives)
     }
 
     private fun generateCode(value: Value<Value<*>>, type: KtTypeName): CodeBlock =

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/kotlin/KotlinEnumTypeGenerator.kt

@@ -21,6 +21,7 @@ package com.netflix.graphql.dgs.codegen.generators.kotlin
 import com.netflix.graphql.dgs.codegen.CodeGenConfig
 import com.netflix.graphql.dgs.codegen.CodeGenResult
 import com.netflix.graphql.dgs.codegen.generators.java.EnumTypeGenerator
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.applyDirectivesKotlin
 import com.netflix.graphql.dgs.codegen.shouldSkip
 import com.squareup.kotlinpoet.FileSpec
@@ -40,7 +41,7 @@ class KotlinEnumTypeGenerator(private val config: CodeGenConfig) {
 
         logger.info("Generating enum type ${definition.name}")
 
-        val kotlinType = TypeSpec.classBuilder(definition.name)
+        val kotlinType = TypeSpec.classBuilder(definition.templatedClassName(config.nameTemplate))
             .addOptionalGeneratedAnnotation(config)
             .addModifiers(KModifier.ENUM)
 

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/kotlin/KotlinInterfaceTypeGenerator.kt

@@ -20,6 +20,7 @@ package com.netflix.graphql.dgs.codegen.generators.kotlin
 
 import com.netflix.graphql.dgs.codegen.CodeGenConfig
 import com.netflix.graphql.dgs.codegen.CodeGenResult
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.shouldSkip
 import com.squareup.kotlinpoet.*
 import graphql.language.*
@@ -46,7 +47,7 @@ class KotlinInterfaceTypeGenerator(private val config: CodeGenConfig, private va
 
         logger.info("Generating type {}", definition.name)
 
-        val interfaceBuilder = TypeSpec.interfaceBuilder(definition.name)
+        val interfaceBuilder = TypeSpec.interfaceBuilder(definition.templatedClassName(config.nameTemplate))
             .addOptionalGeneratedAnnotation(config)
         if (definition.description != null) {
             interfaceBuilder.addKdoc("%L", definition.description.sanitizeKdoc())

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/kotlin2/GenerateKotlin2DataTypes.kt

@@ -32,6 +32,7 @@ import com.netflix.graphql.dgs.codegen.generators.kotlin.jvmNameAnnotation
 import com.netflix.graphql.dgs.codegen.generators.kotlin.sanitizeKdoc
 import com.netflix.graphql.dgs.codegen.generators.kotlin.suppressInapplicableJvmNameAnnotation
 import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.capitalized
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.SchemaExtensionsUtils.findTypeExtensions
 import com.netflix.graphql.dgs.codegen.generators.shared.excludeSchemaTypeExtension
 import com.netflix.graphql.dgs.codegen.shouldSkip
@@ -156,7 +157,7 @@ fun generateKotlin2DataTypes(
                 .build()
 
             // create the data class
-            val typeSpec = TypeSpec.classBuilder(typeDefinition.name)
+            val typeSpec = TypeSpec.classBuilder(typeDefinition.templatedClassName(config.nameTemplate))
                 .addOptionalGeneratedAnnotation(config)
                 // add docs if available
                 .apply {

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/kotlin2/GenerateKotlin2EnumTypes.kt

@@ -22,6 +22,7 @@ import com.netflix.graphql.dgs.codegen.CodeGenConfig
 import com.netflix.graphql.dgs.codegen.generators.kotlin.addEnumConstants
 import com.netflix.graphql.dgs.codegen.generators.kotlin.addOptionalGeneratedAnnotation
 import com.netflix.graphql.dgs.codegen.generators.kotlin.sanitizeKdoc
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.SchemaExtensionsUtils.findEnumExtensions
 import com.netflix.graphql.dgs.codegen.generators.shared.applyDirectivesKotlin
 import com.netflix.graphql.dgs.codegen.generators.shared.excludeSchemaTypeExtension
@@ -55,7 +56,7 @@ fun generateKotlin2EnumTypes(
                 .flatMap { it.enumValueDefinitions }
 
             // create the enum class
-            val enumSpec = TypeSpec.classBuilder(enumDefinition.name)
+            val enumSpec = TypeSpec.classBuilder(enumDefinition.templatedClassName(config.nameTemplate))
                 .addOptionalGeneratedAnnotation(config)
                 .addModifiers(KModifier.ENUM)
                 // add docs if available

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/kotlin2/GenerateKotlin2InputTypes.kt

@@ -23,6 +23,7 @@ import com.netflix.graphql.dgs.codegen.GraphQLInput
 import com.netflix.graphql.dgs.codegen.generators.kotlin.ReservedKeywordFilter
 import com.netflix.graphql.dgs.codegen.generators.kotlin.addOptionalGeneratedAnnotation
 import com.netflix.graphql.dgs.codegen.generators.kotlin.sanitizeKdoc
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.SchemaExtensionsUtils.findInputExtensions
 import com.netflix.graphql.dgs.codegen.generators.shared.excludeSchemaTypeExtension
 import com.netflix.graphql.dgs.codegen.shouldSkip
@@ -69,7 +70,7 @@ fun generateKotlin2InputTypes(
             val typeName = ClassName(config.packageNameTypes, inputDefinition.name)
 
             // create the input class
-            val typeSpec = TypeSpec.classBuilder(typeName)
+            val typeSpec = TypeSpec.classBuilder(inputDefinition.templatedClassName(config.nameTemplate))
                 .addOptionalGeneratedAnnotation(config)
                 // add docs if available
                 .apply {

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/kotlin2/GenerateKotlin2Interfaces.kt

@@ -26,6 +26,7 @@ import com.netflix.graphql.dgs.codegen.generators.kotlin.jsonTypeInfoAnnotation
 import com.netflix.graphql.dgs.codegen.generators.kotlin.jvmNameAnnotation
 import com.netflix.graphql.dgs.codegen.generators.kotlin.sanitizeKdoc
 import com.netflix.graphql.dgs.codegen.generators.kotlin.suppressInapplicableJvmNameAnnotation
+import com.netflix.graphql.dgs.codegen.generators.shared.CodeGeneratorUtils.templatedClassName
 import com.netflix.graphql.dgs.codegen.generators.shared.SchemaExtensionsUtils.findInterfaceExtensions
 import com.netflix.graphql.dgs.codegen.generators.shared.SchemaExtensionsUtils.findUnionExtensions
 import com.netflix.graphql.dgs.codegen.generators.shared.excludeSchemaTypeExtension
@@ -82,7 +83,7 @@ fun generateKotlin2Interfaces(
             val overrideFields = typeLookup.overrideFields(implementedInterfaces)
 
             // create the interface
-            val interfaceSpec = TypeSpec.interfaceBuilder(interfaceDefinition.name)
+            val interfaceSpec = TypeSpec.interfaceBuilder(interfaceDefinition.templatedClassName(config.nameTemplate))
                 .addOptionalGeneratedAnnotation(config)
                 .addModifiers(KModifier.SEALED)
                 // add docs if available

graphql-dgs-codegen-core/src/main/kotlin/com/netflix/graphql/dgs/codegen/generators/shared/CodeGeneratorUtils.kt

@@ -18,6 +18,12 @@
 
 package com.netflix.graphql.dgs.codegen.generators.shared
 
+import graphql.language.EnumTypeDefinition
+import graphql.language.InputObjectTypeDefinition
+import graphql.language.InterfaceTypeDefinition
+import graphql.language.NamedNode
+import graphql.language.ObjectTypeDefinition
+
 object CodeGeneratorUtils {
 
     enum class Case {
@@ -40,6 +46,37 @@ object CodeGeneratorUtils {
 
     fun String.capitalized(): String = replaceFirstChar(Character::toTitleCase)
 
+    /**
+     * Returns the name generated using [nameTemplate]. If [nameTemplate] is null, returns the name of the node.
+     *
+     * The following variables are available in the template:
+     * - name: the original name of the node
+     * - schemaType: the GraphQL Schema type of the node (Type, Input, Interface, Enum)
+     *
+     * Examples:
+     * Given a node named "Person" and schema type "Type", the following templates will generate the following names:
+     * - null -> "Person"
+     * - "{name}GraphQL{schemaType}" -> "PersonGraphQLType"
+     * - "{name}GraphQL" -> "PersonGraphQL"
+     * - "{name}{schemaType}" -> "PersonType"
+     */
+    fun NamedNode<*>.templatedClassName(nameTemplate: String?): String =
+        nameTemplate
+            ?.replace(
+                "{name}",
+                this.name
+            )
+            ?.replace(
+                "{schemaType}",
+                when (this) {
+                    is ObjectTypeDefinition -> "Type"
+                    is InputObjectTypeDefinition -> "Input"
+                    is InterfaceTypeDefinition -> "Interface"
+                    is EnumTypeDefinition -> "Enum"
+                    else -> ""
+                }
+            ) ?: this.name
+
     /**
      * Mostly copied from Apache Commons StringUtils.splitByCharacterType
      */

graphql-dgs-codegen-core/src/test/kotlin/com/netflix/graphql/dgs/codegen/CodeGenTest.kt

@@ -4503,4 +4503,23 @@ It takes a title and such.
         assertThat(dataTypes[0].typeSpec.fieldSpecs[0].initializer.toString()).isEqualTo("Locale.forLanguageTag(\"en-US\")")
         assertCompilesJava(dataTypes)
     }
+
+    @TemplateClassNameTest
+    fun generateSerializedDataClassWithCustomName(
+        schema: String,
+        nameTemplate: String?,
+        expectedName: String
+    ) {
+        val dataTypes = CodeGen(
+            CodeGenConfig(
+                schemas = setOf(schema),
+                packageName = basePackageName,
+                nameTemplate = nameTemplate
+            )
+        )
+            .generate()
+            .javaSources()
+
+        assertThat(dataTypes.firstOrNull()?.typeSpec?.name).isEqualTo(expectedName)
+    }
 }

graphql-dgs-codegen-core/src/test/kotlin/com/netflix/graphql/dgs/codegen/KotlinCodeGenTest.kt

@@ -3732,4 +3732,21 @@ It takes a title and such.
         assertThat(typeSpec.primaryConstructor!!.parameters[0].defaultValue.toString()).isEqualTo("Locale.forLanguageTag(\"en-US\")")
         assertCompilesKotlin(dataTypes)
     }
+
+    @TemplateClassNameTest
+    fun `Should generate class names based on template`(
+        schema: String,
+        nameTemplate: String?,
+        expectedName: String
+    ) {
+        val dataTypes = CodeGen(
+            CodeGenConfig(
+                schemas = setOf(schema),
+                language = Language.KOTLIN,
+                nameTemplate = nameTemplate
+            )
+        ).generate().kotlinSources()
+
+        assertThat(dataTypes.firstOrNull()?.name).isEqualTo(expectedName)
+    }
 }

graphql-dgs-codegen-core/src/test/kotlin/com/netflix/graphql/dgs/codegen/Kotline2CodeGenTest.kt

@@ -28,23 +28,7 @@ import java.io.Serializable
 class Kotline2CodeGenTest {
     @Test
     fun generateSerializableDataClass() {
-        val schema = """
-            type Person {
-                firstname: String
-                lastname: String
-            }
-        """.trimIndent()
-
-        val codeGenResult = CodeGen(
-            CodeGenConfig(
-                schemas = setOf(schema),
-                packageName = basePackageName,
-                language = Language.KOTLIN,
-                generateKotlinNullableClasses = true,
-                generateKotlinClosureProjections = true,
-                implementSerializable = true
-            )
-        ).generate()
+        val codeGenResult = CodeGen(getTestCodeGenConfig()).generate()
 
         val dataTypes = codeGenResult.kotlinDataTypes
 
@@ -92,4 +76,32 @@ class Kotline2CodeGenTest {
         )
         assertCompilesKotlin(result.kotlinEnumTypes)
     }
+
+    @TemplateClassNameTest
+    fun generateSerializedDataClassWithCustomName(
+        schema: String,
+        nameTemplate: String?,
+        expectedName: String
+    ) {
+        val dataTypes = CodeGen(getTestCodeGenConfig(nameTemplate = nameTemplate, schema = schema))
+            .generate()
+            .kotlinSources()
+
+        assertThat(dataTypes.firstOrNull()?.name).isEqualTo(expectedName)
+    }
+
+    companion object {
+        private fun getTestCodeGenConfig(
+            nameTemplate: String? = null,
+            schema: String = PERSON_TYPE_SCHEMA
+        ): CodeGenConfig = CodeGenConfig(
+            schemas = setOf(schema),
+            packageName = basePackageName,
+            language = Language.KOTLIN,
+            generateKotlinNullableClasses = true,
+            generateKotlinClosureProjections = true,
+            implementSerializable = true,
+            nameTemplate = nameTemplate
+        )
+    }
 }