Modifications to customize the code templates to use in code generation. To achieve this feature the follwing changes has been added:

* Modified GraphqlMavenPlugin POJO with new param tempaltes to configure with templates to overwrite. The key is the alias of the template and the value is the classpath resource related to the file. PluginCofiguration and PluginConfigurationTestHelper has been modified to add support to new new property
* CodeGenerator has been modifiied to check if a template has been overwritten. For every invocation to generateTargetFiles, the template to use is resolved with an invocation to the new method resolveTemplate. The maker easier the management of the available templates, all static properties with the classpath resources for the templates has been refactored to a new enumeration: CodeTemplate. Also, each enumeration entry is classfied with it scope: client, server or common (applies to both). The available scopes have also been definied in a new enumeration: CodeTemplateScope

Unit and Integration tests changes:
* Added unit test for CodeGenerator.resolveTemplate
* Added integration tests to validate both custom generation of server an client code: CustomTemplatesClientTest and CustomTemplatesServerTest. Both tests extends AbstractCustomTemplateIntegrationTest wich defines assertions for customized code generation. Spring configuration has been added for each test: CustomTemplates_Client_SpringConfiguration and CustomTemplates_Server_SpringConfiguration. Both configuration extend AbstractCustomTemplatesSpringConfiguration which configures code generation with customized templates
* Customized code templates has been added to graphql-maven-plugin-logic/src/test/resources/tempaltes_personalization. Every templates generates the first line of the file as "/** This template is custom **/"

Author: gonzalogomezgarcia

graphql-maven-plugin-logic/pom.xml

@@ -89,6 +89,11 @@
 			<artifactId>spring-boot-starter-data-jpa</artifactId>
 			<scope>provided</scope>
 		</dependency>
+		<dependency>
+		    <groupId>org.javatuples</groupId>
+		    <artifactId>javatuples</artifactId>
+		    <scope>test</scope>
+		</dependency>
 
 		<!-- Other dependencies -->
 		<dependency>

graphql-maven-plugin-logic/src/main/java/com/graphql_java_generator/plugin/CodeGenerator.java

@@ -47,26 +47,6 @@
 @Component
 public class CodeGenerator {
 
-	// Templates for both client and server generation
-	private static final String PATH_VELOCITY_TEMPLATE_OBJECT = "templates/object_type.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_INTERFACE = "templates/interface_type.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_ENUM = "templates/enum_type.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_UNION = "templates/union_type.vm.java";
-	// Templates for client generation only
-	private static final String PATH_VELOCITY_TEMPLATE_CUSTOM_SCALAR_REGISTRY_INITIALIZER = "templates/client_CustomScalarRegistryInitializer.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_QUERY_MUTATION_SUBSCRIPTION = "templates/client_query_mutation_subscription_type.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_QUERY_TARGET_TYPE = "templates/client_query_target_type.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_JACKSON_DESERIALIZER = "templates/client_jackson_deserialize.vm.java";
-	// Templates for server generation only
-	private static final String PATH_VELOCITY_TEMPLATE_BATCHLOADERDELEGATE = "templates/server_BatchLoaderDelegate.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_BATCHLOADERDELEGATEIMPL = "templates/server_BatchLoaderDelegateImpl.vm.java";
-	// private static final String PATH_VELOCITY_TEMPLATE_CUSTOM_SCALARS = "templates/server_GraphQLScalarType.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_DATAFETCHER = "templates/server_GraphQLDataFetchers.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_DATAFETCHERDELEGATE = "templates/server_GraphQLDataFetchersDelegate.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_GRAPHQLUTIL = "templates/server_GraphQLUtil.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_PROVIDER = "templates/server_GraphQLProvider.vm.java";
-	private static final String PATH_VELOCITY_TEMPLATE_SERVER = "templates/server_GraphQLServerMain.vm.java";
-
 	public static final String FILE_TYPE_JACKSON_DESERIALIZER = "Jackson deserializer";
 
 	@Autowired
@@ -103,33 +83,33 @@ public CodeGenerator() {
 	public int generateCode() throws IOException {
 
 		int i = 0;
-		i += generateTargetFiles(documentParser.getObjectTypes(), "object", PATH_VELOCITY_TEMPLATE_OBJECT);
-		i += generateTargetFiles(documentParser.getInterfaceTypes(), "interface", PATH_VELOCITY_TEMPLATE_INTERFACE);
-		i += generateTargetFiles(documentParser.getUnionTypes(), "union", PATH_VELOCITY_TEMPLATE_UNION);
-		i += generateTargetFiles(documentParser.getEnumTypes(), "enum", PATH_VELOCITY_TEMPLATE_ENUM);
+		i += generateTargetFiles(documentParser.getObjectTypes(), "object", resolveTemplate(CodeTemplate.OBJECT));
+		i += generateTargetFiles(documentParser.getInterfaceTypes(), "interface", resolveTemplate(CodeTemplate.INTERFACE));
+		i += generateTargetFiles(documentParser.getUnionTypes(), "union", resolveTemplate(CodeTemplate.UNION));
+		i += generateTargetFiles(documentParser.getEnumTypes(), "enum", resolveTemplate(CodeTemplate.ENUM));
 
 		switch (pluginConfiguration.getMode()) {
 		case server:
 			i += generateServerFiles();
 			break;
 		case client:
 			i += generateTargetFiles(documentParser.getQueryTypes(), "query",
-					PATH_VELOCITY_TEMPLATE_QUERY_MUTATION_SUBSCRIPTION);
+					resolveTemplate(CodeTemplate.QUERY_MUTATION_SUBSCRIPTION));
 			i += generateTargetFiles(documentParser.getMutationTypes(), "mutation",
-					PATH_VELOCITY_TEMPLATE_QUERY_MUTATION_SUBSCRIPTION);
+					resolveTemplate(CodeTemplate.QUERY_MUTATION_SUBSCRIPTION));
 			i += generateTargetFiles(documentParser.getSubscriptionTypes(), "subscription",
-					PATH_VELOCITY_TEMPLATE_QUERY_MUTATION_SUBSCRIPTION);
+					resolveTemplate(CodeTemplate.QUERY_MUTATION_SUBSCRIPTION));
 
 			// Files for Custom Scalars
 			VelocityContext context = new VelocityContext();
 			context.put("pluginConfiguration", pluginConfiguration);
 			context.put("customScalars", documentParser.customScalars);
 			i += generateOneFile(getJavaFile("CustomScalarRegistryInitializer"),
 					"Generating CustomScalarRegistryInitializer", context,
-					PATH_VELOCITY_TEMPLATE_CUSTOM_SCALAR_REGISTRY_INITIALIZER);
+					resolveTemplate(CodeTemplate.CUSTOM_SCALAR_REGISTRY_INITIALIZER));
 			//
 			i += generateTargetFiles(documentParser.customScalars, FILE_TYPE_JACKSON_DESERIALIZER,
-					PATH_VELOCITY_TEMPLATE_JACKSON_DESERIALIZER);
+					resolveTemplate(CodeTemplate.JACKSON_DESERIALIZER));
 			i += generateQueryTargetType();
 			break;
 		}
@@ -223,7 +203,7 @@ int generateQueryTargetType() {
 				context.put("objectName", objectName);
 				context.put("query", query);
 
-				i += generateOneFile(targetFile, msg, context, PATH_VELOCITY_TEMPLATE_QUERY_TARGET_TYPE);
+				i += generateOneFile(targetFile, msg, context, resolveTemplate(CodeTemplate.QUERY_TARGET_TYPE));
 			}
 		}
 		return i;
@@ -253,28 +233,28 @@ int generateServerFiles() throws IOException {
 
 		int ret = 0;
 		ret += generateOneFile(getJavaFile("GraphQLServerMain"), "generating GraphQLServerMain", context,
-				PATH_VELOCITY_TEMPLATE_SERVER);
+				resolveTemplate(CodeTemplate.SERVER));
 		ret += generateOneFile(getJavaFile("GraphQLProvider"), "generating GraphQLProvider", context,
-				PATH_VELOCITY_TEMPLATE_PROVIDER);
+				resolveTemplate(CodeTemplate.PROVIDER));
 		ret += generateOneFile(getJavaFile("GraphQLDataFetchers"), "generating GraphQLDataFetchers", context,
-				PATH_VELOCITY_TEMPLATE_DATAFETCHER);
+				resolveTemplate(CodeTemplate.DATAFETCHER));
 		ret += generateOneFile(getJavaFile("GraphQLUtil"), "generating GraphQLUtil", context,
-				PATH_VELOCITY_TEMPLATE_GRAPHQLUTIL);
+				resolveTemplate(CodeTemplate.GRAPHQLUTIL));
 
 		for (DataFetchersDelegate dataFetcherDelegate : documentParser.dataFetchersDelegates) {
 			context.put("dataFetcherDelegate", dataFetcherDelegate);
 			ret += generateOneFile(getJavaFile(dataFetcherDelegate.getPascalCaseName()),
 					"generating " + dataFetcherDelegate.getPascalCaseName(), context,
-					PATH_VELOCITY_TEMPLATE_DATAFETCHERDELEGATE);
+					resolveTemplate(CodeTemplate.DATAFETCHERDELEGATE));
 		}
 
 		ret += generateOneFile(getJavaFile("BatchLoaderDelegate"), "generating BatchLoaderDelegate", context,
-				PATH_VELOCITY_TEMPLATE_BATCHLOADERDELEGATE);
+				resolveTemplate(CodeTemplate.BATCHLOADERDELEGATE));
 		for (BatchLoader batchLoader : documentParser.batchLoaders) {
 			String name = "BatchLoaderDelegate" + batchLoader.getType().getClassSimpleName() + "Impl";
 			context.put("batchLoader", batchLoader);
 			ret += generateOneFile(getJavaFile(name), "generating " + name, context,
-					PATH_VELOCITY_TEMPLATE_BATCHLOADERDELEGATEIMPL);
+					resolveTemplate(CodeTemplate.BATCHLOADERDELEGATEIMPL));
 		}
 
 		return ret;
@@ -393,4 +373,18 @@ List<String> getImportList() {
 		}
 		return ret;
 	}
+	
+	/**
+	 * Resolves the template for the given key
+	 * @param templateKey
+	 * @param defaultValue
+	 * @return
+	 */
+	protected String resolveTemplate(CodeTemplate template) {
+		if(pluginConfiguration.getTemplates().containsKey(template.name())) {
+			return pluginConfiguration.getTemplates().get(template.name());
+		} else {
+			return template.getDefaultValue();
+		}
+	}
 }

graphql-maven-plugin-logic/src/main/java/com/graphql_java_generator/plugin/CodeTemplate.java

@@ -0,0 +1,49 @@
+package com.graphql_java_generator.plugin;
+
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NonNull;
+import lombok.RequiredArgsConstructor;
+
+/**
+ * Enumeration that defines the available templates for code generation
+ * @author ggomez
+ *
+ */
+@Getter
+@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
+public enum CodeTemplate {
+	
+	
+	OBJECT(CodeTemplateScope.COMMON, "templates/object_type.vm.java"),
+	INTERFACE(CodeTemplateScope.COMMON, "templates/interface_type.vm.java"),
+	ENUM(CodeTemplateScope.COMMON, "templates/enum_type.vm.java"),
+	UNION(CodeTemplateScope.COMMON, "templates/union_type.vm.java"),
+	CUSTOM_SCALAR_REGISTRY_INITIALIZER(CodeTemplateScope.CLIENT, "templates/client_CustomScalarRegistryInitializer.vm.java"),
+	QUERY_MUTATION_SUBSCRIPTION(CodeTemplateScope.CLIENT, "templates/client_query_mutation_subscription_type.vm.java"),
+	QUERY_TARGET_TYPE(CodeTemplateScope.CLIENT, "templates/client_query_target_type.vm.java"),
+	JACKSON_DESERIALIZER(CodeTemplateScope.CLIENT, "templates/client_jackson_deserialize.vm.java"),
+	BATCHLOADERDELEGATE(CodeTemplateScope.SERVER, "templates/server_BatchLoaderDelegate.vm.java"),
+	BATCHLOADERDELEGATEIMPL(CodeTemplateScope.SERVER, "templates/server_BatchLoaderDelegateImpl.vm.java"),
+	DATAFETCHER(CodeTemplateScope.SERVER, "templates/server_GraphQLDataFetchers.vm.java"),
+	DATAFETCHERDELEGATE(CodeTemplateScope.SERVER, "templates/server_GraphQLDataFetchersDelegate.vm.java"),
+	GRAPHQLUTIL(CodeTemplateScope.SERVER, "templates/server_GraphQLUtil.vm.java"),
+	PROVIDER(CodeTemplateScope.SERVER, "templates/server_GraphQLProvider.vm.java"),
+	SERVER(CodeTemplateScope.SERVER, "templates/server_GraphQLServerMain.vm.java");	
+	
+	/**
+	 * The de
+	 */
+	@NonNull
+	private CodeTemplateScope scope;
+	
+	/**
+	 * The default value to use
+	 */
+	@NonNull
+	private String defaultValue;
+
+	
+	
+
+}

graphql-maven-plugin-logic/src/main/java/com/graphql_java_generator/plugin/CodeTemplateScope.java

@@ -0,0 +1,25 @@
+package com.graphql_java_generator.plugin;
+
+/**
+ * Enumeration that defines the {@link CodeTemplate} scopes avaible
+ * @author ggomez
+ *
+ */
+public enum CodeTemplateScope {
+	
+	/**
+	 * Scope for just client code
+	 */
+	CLIENT,
+	
+	/**
+	 * Scope for server code
+	 */
+	SERVER,
+	
+	/**
+	 * Scope for both client and server code
+	 */
+	COMMON;
+
+}

graphql-maven-plugin-logic/src/main/java/com/graphql_java_generator/plugin/PluginConfiguration.java

@@ -108,7 +108,12 @@ public interface PluginConfiguration {
 
 	/** The folder where the generated classes will be generated */
 	public File getTargetSourceFolder();
-
+	
+	/**
+	 * The overwritting templates
+	 */
+	public Map<String, String> getTemplates();
+	
 	/**
 	 * Returns true if shall copy graphql sources (graphql-java-runtime) source code
 	 * @return
@@ -129,6 +134,8 @@ default public void logConfiguration() {
 			getLog().debug("  TargetClassFolder: " + getTargetClassFolder());
 			getLog().debug("  TargetSourceFolder: " + getTargetSourceFolder());
 			getLog().debug("  CopyGraphQLJavaSources: " + isCopyGraphQLJavaSources());
+			getLog().debug("  Templates: " +  (Objects.nonNull(getTemplates())? 
+					getTemplates().entrySet().stream().map(entry -> String.format("%s=%s", entry.getKey(), entry.getValue())).collect(Collectors.joining(", ")): StringUtils.EMPTY) );
 		}
 	}
 }

graphql-maven-plugin-logic/src/test/java/com/graphql_java_generator/plugin/CodeGeneratorTest.java

@@ -1,9 +1,9 @@
 package com.graphql_java_generator.plugin;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
-import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.mock;
@@ -47,7 +47,6 @@
 @ContextConfiguration(classes = { AllGraphQLCases_Server_SpringConfiguration.class })
 class CodeGeneratorTest {
 
-
 	@Resource
 	ApplicationContext context;
 	@Resource
@@ -252,6 +251,26 @@ void testGenerateCode_skipCopySources() throws IOException {
 		assertFalse(targetRuntimeClassesSourceFolder.exists());
 	}
 
+	/**
+	 * Test for validating default template resolution
+	 */
+	@Test
+	@DirtiesContext
+	protected void testResolveTemplateDefault() {
+		pluginConfiguration.templates.clear();
+		assertEquals(CodeTemplate.BATCHLOADERDELEGATE.getDefaultValue(), this.codeGenerator.resolveTemplate(CodeTemplate.BATCHLOADERDELEGATE));;
+	}
+
+	/**
+	 * Test for validating customized template resolution
+	 */
+	@Test
+	@DirtiesContext
+	protected void testResolveTemplateCustom() {
+		pluginConfiguration.templates.clear();
+		pluginConfiguration.templates.put(CodeTemplate.BATCHLOADERDELEGATE.name(), "/my/custom/template");
+		assertEquals("/my/custom/template", this.codeGenerator.resolveTemplate(CodeTemplate.BATCHLOADERDELEGATE));;
+	}
 
 	/**
 	 * Creates a mock graphql-java-runtime-sources.jar

graphql-maven-plugin-logic/src/test/java/com/graphql_java_generator/plugin/compilation_tests/AbstractCustomTemplateIntegrationTest.java

@@ -0,0 +1,39 @@
+package com.graphql_java_generator.plugin.compilation_tests;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.File;
+import java.util.Arrays;
+
+import org.apache.commons.io.FileUtils;
+
+/**
+ * Base integration test for Custom templates scenario
+ * Offers methods to assert customized code validation
+ * @author ggomez
+ *
+ */
+public abstract class AbstractCustomTemplateIntegrationTest extends AbstractIntegrationTest {
+	
+	protected static final String CUSTOMIZED_CODE_FIRST_LINE = "/** This template is custom **/";
+	
+	/**
+	 * Helper method that validates that given dir contains files generated with custom templates
+	 * Custom template file are identified by it's first line. It's value is \/** This template is custom **\/
+	 * @param generatedSourcesDir
+	 */
+	protected void assertCustomTemplateGeneration(File sourcesDirectory) {
+		// Validate that every file generated has been generated with the templates in src/test/resources/templates_personalization
+		Arrays.stream(sourcesDirectory.listFiles())
+			.filter(generatedFile -> generatedFile.exists() && generatedFile.isFile())
+			.forEach(generatedFile-> {
+				try {
+					assertEquals(CUSTOMIZED_CODE_FIRST_LINE, FileUtils.readLines(generatedFile, "UTF-8").get(0));					
+				} catch(Exception e) {
+					throw new RuntimeException(e);
+				}
+			});
+	}
+		
+
+}

graphql-maven-plugin-logic/src/test/java/com/graphql_java_generator/plugin/compilation_tests/CustomTemplatesClientTest.java

@@ -0,0 +1,46 @@
+package com.graphql_java_generator.plugin.compilation_tests;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import graphql.mavenplugin_notscannedbyspring.CustomTemplates_Client_SpringConfiguration;
+
+@ExtendWith(SpringExtension.class)
+@ContextConfiguration(classes = { CustomTemplates_Client_SpringConfiguration.class })
+class CustomTemplatesClientTest extends AbstractCustomTemplateIntegrationTest {
+
+	// Everything is in the AbstractIntegrationTest class.
+
+	// The only aim of this class, is to have its own Spring Configuration
+	@BeforeEach
+	public void setUp() throws IOException {
+		graphqlTestHelper.checkSchemaStringProvider("allGraphQLCases.graphqls");
+	}
+	
+	/**
+	 * This test will be executed for each concrete subclass of this class
+	 * 
+	 * @throws MojoExecutionException
+	 * @throws IOException
+	 */
+	@Test
+	@DirtiesContext // We need to forget the previous parsing (or everything may be doubled)
+	void testGenerateCode() throws IOException {
+		super.testGenerateCode();
+		
+		// Validate that every file generated has been generated with the templates in src/test/resources/templates_personalization
+		File generatedSourcesDir = new File(this.pluginConfiguration.getTargetSourceFolder(), pluginConfiguration.getPackageName().replaceAll("\\.", File.separator));
+		assertCustomTemplateGeneration(generatedSourcesDir);
+		
+		
+	}
+
+	
+}