Allow extensions-only schema #160 (#162)

Author: kobylynskyi

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

@@ -217,7 +217,9 @@ private File generateEnum(MappingContext mappingContext, ExtendedEnumTypeDefinit
 
     private void initCustomTypeMappings(Collection<ExtendedScalarTypeDefinition> scalarTypeDefinitions) {
         for (ExtendedScalarTypeDefinition definition : scalarTypeDefinitions) {
-            mappingConfig.putCustomTypeMappingIfAbsent(definition.getDefinition().getName(), "String");
+            if (definition.getDefinition() != null) {
+                mappingConfig.putCustomTypeMappingIfAbsent(definition.getDefinition().getName(), "String");
+            }
             for (ScalarTypeExtensionDefinition extension : definition.getExtensions()) {
                 mappingConfig.putCustomTypeMappingIfAbsent(extension.getName(), "String");
             }

src/main/java/com/kobylynskyi/graphql/codegen/model/definitions/ExtendedDefinition.java

@@ -1,12 +1,15 @@
 package com.kobylynskyi.graphql.codegen.model.definitions;
 
-import graphql.language.*;
+import graphql.language.Comment;
+import graphql.language.NamedNode;
+import graphql.language.Node;
 import lombok.Getter;
-import lombok.NonNull;
 import lombok.Setter;
 
-import java.util.*;
-import java.util.function.Function;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
 
 /**
  * Base class for all GraphQL definition types that contains base definition and its extensions
@@ -18,17 +21,23 @@
 @Setter
 public abstract class ExtendedDefinition<T extends NamedNode<T>, E extends T> {
 
-    @NonNull
+    /**
+     * Nullable because some schemas can have just "extends"
+     */
     protected T definition;
     protected List<E> extensions = new ArrayList<>();
 
     public String getName() {
-        return definition.getName();
+        if (definition != null) {
+            return definition.getName();
+        } else {
+            return extensions.stream().map(NamedNode::getName).findFirst().orElse(null);
+        }
     }
 
     public List<String> getJavaDoc() {
         List<String> comments = new ArrayList<>();
-        if (definition.getComments() != null) {
+        if (definition != null && definition.getComments() != null) {
             definition.getComments().stream()
                     .map(Comment::getContent)
                     .filter(Objects::nonNull)

src/main/java/com/kobylynskyi/graphql/codegen/model/definitions/ExtendedEnumTypeDefinition.java

@@ -4,6 +4,7 @@
 import graphql.language.EnumTypeExtensionDefinition;
 import graphql.language.EnumValueDefinition;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class ExtendedEnumTypeDefinition extends ExtendedDefinition<EnumTypeDefinition, EnumTypeExtensionDefinition> {
@@ -14,7 +15,10 @@ public class ExtendedEnumTypeDefinition extends ExtendedDefinition<EnumTypeDefin
      * @return list of all enum value definitions
      */
     public List<EnumValueDefinition> getValueDefinitions() {
-        List<EnumValueDefinition> definitions = definition.getEnumValueDefinitions();
+        List<EnumValueDefinition> definitions = new ArrayList<>();
+        if (definition != null) {
+            definitions.addAll(definition.getEnumValueDefinitions());
+        }
         extensions.stream()
                 .map(EnumTypeExtensionDefinition::getEnumValueDefinitions)
                 .forEach(definitions::addAll);

src/main/java/com/kobylynskyi/graphql/codegen/model/definitions/ExtendedInputObjectTypeDefinition.java

@@ -4,12 +4,16 @@
 import graphql.language.InputObjectTypeExtensionDefinition;
 import graphql.language.InputValueDefinition;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class ExtendedInputObjectTypeDefinition extends ExtendedDefinition<InputObjectTypeDefinition, InputObjectTypeExtensionDefinition> {
 
     public List<InputValueDefinition> getValueDefinitions() {
-        List<InputValueDefinition> definitions = definition.getInputValueDefinitions();
+        List<InputValueDefinition> definitions = new ArrayList<>();
+        if (definition != null) {
+            definitions.addAll(definition.getInputValueDefinitions());
+        }
         extensions.stream()
                 .map(InputObjectTypeDefinition::getInputValueDefinitions)
                 .forEach(definitions::addAll);

src/main/java/com/kobylynskyi/graphql/codegen/model/definitions/ExtendedInterfaceTypeDefinition.java

@@ -11,9 +11,11 @@ public class ExtendedInterfaceTypeDefinition extends ExtendedDefinition<Interfac
 
     public List<ExtendedFieldDefinition> getFieldDefinitions() {
         List<ExtendedFieldDefinition> definitions = new ArrayList<>();
-        definition.getFieldDefinitions().stream()
-                .map(f -> new ExtendedFieldDefinition(f, false))
-                .forEach(definitions::add);
+        if (definition != null) {
+            definition.getFieldDefinitions().stream()
+                    .map(f -> new ExtendedFieldDefinition(f, false))
+                    .forEach(definitions::add);
+        }
         extensions.stream()
                 .map(InterfaceTypeExtensionDefinition::getFieldDefinitions)
                 .flatMap(Collection::stream)

src/main/java/com/kobylynskyi/graphql/codegen/model/definitions/ExtendedObjectTypeDefinition.java

@@ -1,6 +1,8 @@
 package com.kobylynskyi.graphql.codegen.model.definitions;
 
-import graphql.language.*;
+import graphql.language.ObjectTypeDefinition;
+import graphql.language.ObjectTypeExtensionDefinition;
+import graphql.language.Type;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -10,9 +12,11 @@ public class ExtendedObjectTypeDefinition extends ExtendedDefinition<ObjectTypeD
 
     public List<ExtendedFieldDefinition> getFieldDefinitions() {
         List<ExtendedFieldDefinition> definitions = new ArrayList<>();
-        definition.getFieldDefinitions().stream()
-                .map(f -> new ExtendedFieldDefinition(f, false))
-                .forEach(definitions::add);
+        if (definition != null) {
+            definition.getFieldDefinitions().stream()
+                    .map(f -> new ExtendedFieldDefinition(f, false))
+                    .forEach(definitions::add);
+        }
         extensions.stream()
                 .map(ObjectTypeExtensionDefinition::getFieldDefinitions)
                 .flatMap(Collection::stream)
@@ -23,7 +27,10 @@ public List<ExtendedFieldDefinition> getFieldDefinitions() {
 
     @SuppressWarnings("rawtypes")
     public List<Type> getImplements() {
-        List<Type> definitionImplements = definition.getImplements();
+        List<Type> definitionImplements = new ArrayList<>();
+        if (definition != null) {
+            definitionImplements.addAll(definition.getImplements());
+        }
         extensions.stream()
                 .map(ObjectTypeDefinition::getImplements)
                 .forEach(definitionImplements::addAll);

src/main/java/com/kobylynskyi/graphql/codegen/model/definitions/ExtendedUnionTypeDefinition.java

@@ -27,11 +27,13 @@ public boolean isDefinitionPartOfUnion(ExtendedDefinition<?, ?> definition) {
 
     private Set<String> getMemberTypeNames() {
         Set<String> memberTypeNames = new HashSet<>();
-        getDefinition().getMemberTypes().stream()
-                .map(NamedNode.class::cast)
-                .map(NamedNode::getName)
-                .forEach(memberTypeNames::add);
-        getExtensions().stream()
+        if (definition != null) {
+            definition.getMemberTypes().stream()
+                    .map(NamedNode.class::cast)
+                    .map(NamedNode::getName)
+                    .forEach(memberTypeNames::add);
+        }
+        extensions.stream()
                 .map(UnionTypeDefinition::getMemberTypes)
                 .flatMap(Collection::stream)
                 .map(NamedNode.class::cast)

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

@@ -56,6 +56,17 @@ void generateServerSideClasses() throws Exception {
         }
     }
 
+    @Test
+    void generate_onlyExtend() throws Exception {
+        schemaFinder.setIncludePattern("only-extend-queries.*\\.graphqls");
+        new GraphQLCodegen(schemaFinder.findSchemas(), outputBuildDir, mappingConfig).generate();
+
+        assertEquals(new HashSet<>(asList("Subscription.java", "UserQuery.java", "User.java",
+                "UsersCreatedSubscription.java", "CreateUserMutation.java", "Mutation.java", "Query.java",
+                "UserInput.java")), Arrays.stream(Objects.requireNonNull(outputJavaClassesDir.listFiles()))
+                .map(File::getName).collect(toSet()));
+    }
+
     @Test
     void generateServerSideClasses_ExtensionFieldsResolvers() throws Exception {
         mappingConfig.setGenerateExtensionFieldsResolvers(true);

src/test/resources/schemas/only-extend-queries.graphqls

@@ -0,0 +1,20 @@
+extend type Query {
+    user(userId: ID!): User
+}
+
+extend type Mutation {
+    createUser(input: UserInput!): User
+}
+
+extend type Subscription {
+    usersCreated: [User]
+}
+
+type User {
+    id: ID!
+    name: String!
+}
+
+input UserInput {
+    name: String!
+}