Support for async resolvers (#26)

* Support for async resolvers

Solves issue: #24

* #24 Refactors and fixes

* Renamed asyncApi to generateAsyncApi in MappingConfig
* Changes for adding java.util.concurrent import when it comes to async Query or Mutation
* Improved tests coverage

Author: ReneBL

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

@@ -31,7 +31,7 @@ public static Map<String, Object> map(MappingConfig mappingConfig, FieldDefiniti
         Map<String, Object> dataModel = new HashMap<>();
         String packageName = MapperUtils.getApiPackageName(mappingConfig);
         dataModel.put(PACKAGE, packageName);
-        dataModel.put(IMPORTS, MapperUtils.getImports(mappingConfig, packageName));
+        dataModel.put(IMPORTS, MapperUtils.getImportsForFieldDefinition(mappingConfig, packageName, objectTypeName));
         dataModel.put(CLASS_NAME, getClassName(fieldDefinition.getName(), objectTypeName));
         OperationDefinition operation = mapFieldDefinition(mappingConfig, fieldDefinition, objectTypeName);
         dataModel.put(OPERATIONS, Collections.singletonList(operation));
@@ -50,7 +50,7 @@ static OperationDefinition mapFieldDefinition(MappingConfig mappingConfig, Field
         OperationDefinition operation = new OperationDefinition();
         operation.setName(fieldDef.getName());
         String javaType = GraphqlTypeToJavaTypeMapper.getJavaType(mappingConfig, fieldDef.getType(), fieldDef.getName(), parentTypeName);
-        operation.setType(GraphqlTypeToJavaTypeMapper.wrapIntoSubscriptionIfRequired(mappingConfig, javaType, parentTypeName));
+        operation.setType(GraphqlTypeToJavaTypeMapper.wrapIntoAsyncIfRequired(mappingConfig, javaType, parentTypeName));
         operation.setAnnotations(GraphqlTypeToJavaTypeMapper.getAnnotations(mappingConfig, fieldDef.getType(), fieldDef.getName(), parentTypeName));
         operation.setParameters(InputValueDefinitionToParameterMapper.map(mappingConfig, fieldDef.getInputValueDefinitions(), fieldDef.getName()));
         return operation;

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

@@ -167,6 +167,32 @@ private static String wrapIntoJavaCollection(String type) {
         return String.format("Collection<%s>", type);
     }
 
+    /**
+     * Wrap java type into {@link java.util.concurrent.CompletableFuture}. E.g.: "String" becomes "CompletableFuture<String>"
+     *
+     * @param type Anything that will be wrapped into CompletableFuture<>
+     * @return String wrapped into CompletableFuture<>
+     */
+    private static String wrapIntoJavaCompletableFuture(String type) {
+        return String.format("CompletableFuture<%s>", type);
+    }
+
+    /**
+     * Wraps type taking into account if an async api is needed, whether it is a Query, Mutation or Subscription
+     *
+     * @param mappingConfig  Global mapping configuration
+     * @param javaTypeName   The type that will be wrapped into
+     * @param parentTypeName Name of the parent type
+     * @return Java type wrapped into the subscriptionReturnType
+     */
+    static String wrapIntoAsyncIfRequired(MappingConfig mappingConfig, String javaTypeName, String parentTypeName) {
+        if (MapperUtils.isAsyncQueryOrMutation(mappingConfig, parentTypeName)) {
+            return wrapIntoJavaCompletableFuture(javaTypeName);
+        }
+
+        return wrapIntoSubscriptionIfRequired(mappingConfig, javaTypeName, parentTypeName);
+    }
+
     /**
      * Wraps type into subscriptionReturnType (defined in the mapping configuration.
      * Example:

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

@@ -4,6 +4,7 @@
 import com.kobylynskyi.graphql.codegen.utils.Utils;
 import graphql.language.Document;
 import graphql.language.NamedNode;
+import graphql.language.OperationDefinition.Operation;
 import graphql.language.UnionTypeDefinition;
 
 import java.util.Arrays;
@@ -158,4 +159,37 @@ static Set<String> getImports(MappingConfig mappingConfig, String packageName) {
         imports.add("java.util");
         return imports;
     }
+
+    /**
+     * Returns imports required for the particular case of field definitions (operations), taking into account async
+     * operations, etc.
+     *
+     * @param mappingConfig
+     * @param packageName
+     * @param objectTypeName
+     * @return
+     */
+    static Set<String> getImportsForFieldDefinition(MappingConfig mappingConfig, String packageName, String objectTypeName) {
+        final Set<String> imports = getImports(mappingConfig, packageName);
+
+        if (isAsyncQueryOrMutation(mappingConfig, objectTypeName)) {
+            imports.add("java.util.concurrent");
+        }
+
+        return imports;
+    }
+
+    /**
+     * Determines if the specified operation is an async query or mutation
+     *
+     * @param mappingConfig
+     * @param objectTypeName
+     * @return true if the given operation is an async query or mutation, false otherwise
+     */
+    static boolean isAsyncQueryOrMutation(MappingConfig mappingConfig, String objectTypeName) {
+        boolean isAsyncApi = mappingConfig.getGenerateAsyncApi() != null && mappingConfig.getGenerateAsyncApi().booleanValue();
+
+        return isAsyncApi && (Operation.QUERY.name().equalsIgnoreCase(objectTypeName) || Operation.MUTATION.name()
+                .equalsIgnoreCase(objectTypeName));
+    }
 }

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

@@ -29,7 +29,7 @@ public static Map<String, Object> map(MappingConfig mappingConfig, ObjectTypeDef
         Map<String, Object> dataModel = new HashMap<>();
         String packageName = MapperUtils.getApiPackageName(mappingConfig);
         dataModel.put(PACKAGE, packageName);
-        dataModel.put(IMPORTS, MapperUtils.getImports(mappingConfig, packageName));
+        dataModel.put(IMPORTS, MapperUtils.getImportsForFieldDefinition(mappingConfig, packageName, typeDefinition.getName()));
         dataModel.put(CLASS_NAME, Utils.capitalize(typeDefinition.getName()));
         List<Object> operations = typeDefinition.getFieldDefinitions().stream()
                 .map(fieldDef ->

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

@@ -1,9 +1,7 @@
 package com.kobylynskyi.graphql.codegen.model;
 
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Map;
-import java.util.Set;
 
 import lombok.Data;
 
@@ -39,6 +37,7 @@ public class MappingConfig implements Combinable<MappingConfig> {
     private String subscriptionReturnType;
     private Boolean generateEqualsAndHashCode;
     private Boolean generateToString;
+    private Boolean generateAsyncApi;
 
 
     /**
@@ -81,5 +80,6 @@ public void combine(MappingConfig source) {
         this.subscriptionReturnType = source.subscriptionReturnType  != null ? source.subscriptionReturnType : this.subscriptionReturnType;
         this.generateEqualsAndHashCode = source.generateEqualsAndHashCode != null ? source.generateEqualsAndHashCode : this.generateEqualsAndHashCode;
         this.generateToString = source.generateToString != null ? source.generateToString : this.generateToString;
+        this.generateAsyncApi = source.generateAsyncApi != null? source.generateAsyncApi : this.generateAsyncApi;
     }
 }

src/test/java/com/kobylynskyi/graphql/codegen/GraphqlCodegenTest.java

@@ -1,30 +1,24 @@
 package com.kobylynskyi.graphql.codegen;
 
-import static java.util.stream.Collectors.toList;
-import static org.hamcrest.MatcherAssert.assertThat;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
-import static org.junit.jupiter.api.Assertions.fail;
-
-import java.io.File;
-import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.nio.file.NoSuchFileException;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Objects;
-
+import com.kobylynskyi.graphql.codegen.model.MappingConfig;
+import com.kobylynskyi.graphql.codegen.utils.Utils;
+import org.hamcrest.Matchers;
 import org.hamcrest.core.StringContains;
 import org.hamcrest.core.StringStartsWith;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import com.kobylynskyi.graphql.codegen.model.MappingConfig;
-import com.kobylynskyi.graphql.codegen.utils.Utils;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.nio.file.NoSuchFileException;
+import java.util.*;
+
+import static java.util.stream.Collectors.toList;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
 
 class GraphqlCodegenTest {
 
@@ -343,4 +337,59 @@ void generate_OnlyModel() throws Exception {
         assertEquals(Arrays.asList("Event.java", "EventProperty.java", "EventStatus.java"), generatedFileNames);
     }
 
+    @Test
+    void generate_WithoutAsyncApis() throws Exception {
+        mappingConfig.setGenerateAsyncApi(false);
+        generator.generate();
+
+        File[] files = Objects.requireNonNull(outputJavaClassesDir.listFiles());
+        assertFileContainsElements(files, "VersionQuery.java", "String version()");
+    }
+
+    @Test
+    void generate_AsyncQueryApis() throws Exception {
+        mappingConfig.setGenerateAsyncApi(true);
+        generator.generate();
+
+        File[] files = Objects.requireNonNull(outputJavaClassesDir.listFiles());
+
+        String importJavaUtilConcurrent = "import java.util.concurrent";
+
+        assertFileContainsElements(files, "VersionQuery.java", importJavaUtilConcurrent,
+                "CompletableFuture<String> version()");
+
+        assertFileContainsElements(files, "EventsByCategoryAndStatusQuery.java", importJavaUtilConcurrent,
+                "CompletableFuture<Collection<Event>> eventsByCategoryAndStatus(");
+
+        assertFileContainsElements(files, "EventByIdQuery.java", importJavaUtilConcurrent,
+                "CompletableFuture<Event> eventById(");
+
+    }
+
+    @Test
+    void generate_AsyncMutationApis() throws Exception {
+        mappingConfig.setGenerateAsyncApi(true);
+        generator.generate();
+
+        File[] files = Objects.requireNonNull(outputJavaClassesDir.listFiles());
+
+        assertFileContainsElements(files, "CreateEventMutation.java",
+                "import java.util.concurrent","CompletableFuture<Event> createEvent(");
+
+    }
+
+    private void assertFileContainsElements(File[] files, String fileName, String...elements)
+            throws IOException {
+        File file = getFile(files, fileName);
+
+        assertNotNull(file);
+
+        String fileContent = Utils.getFileContent(file.getPath());
+        assertThat(fileContent, Matchers.stringContainsInOrder(elements));
+    }
+
+    private File getFile(File[] files, String fileName) {
+        return Arrays.stream(files).filter(f -> f.getName().equals(fileName)).findFirst().get();
+    }
+
 }

src/test/java/com/kobylynskyi/graphql/codegen/model/MappingConfigTest.java

@@ -67,6 +67,7 @@ void combineCustomWithDefault() {
         assertEquals("ModelValidationAnnotation", mappingConfig.getModelValidationAnnotation());
         assertEquals("PackageName", mappingConfig.getPackageName());
         assertEquals("SubscriptionsReturnType", mappingConfig.getSubscriptionReturnType());
+        assertFalse(mappingConfig.getGenerateAsyncApi());
     }
 
     @Test
@@ -88,6 +89,7 @@ void combineCustomWithCustom() {
         assertEquals("ModelValidationAnnotation2", mappingConfig.getModelValidationAnnotation());
         assertEquals("PackageName2", mappingConfig.getPackageName());
         assertEquals("SubscriptionsReturnType2", mappingConfig.getSubscriptionReturnType());
+        assertTrue(mappingConfig.getGenerateAsyncApi());
     }
 
     private static Map<String, String> hashMap(AbstractMap.SimpleEntry<String, String>... entries) {
@@ -109,6 +111,7 @@ private static MappingConfig buildMappingConfig() {
         config.setModelValidationAnnotation("ModelValidationAnnotation");
         config.setPackageName("PackageName");
         config.setSubscriptionReturnType("SubscriptionsReturnType");
+        config.setGenerateAsyncApi(false);
         return config;
     }
 
@@ -126,6 +129,7 @@ private static MappingConfig buildMappingConfig2() {
         config.setModelValidationAnnotation("ModelValidationAnnotation2");
         config.setPackageName("PackageName2");
         config.setSubscriptionReturnType("SubscriptionsReturnType2");
+        config.setGenerateAsyncApi(true);
         return config;
     }