Use java.util.List for GQL lists (#186)

Author: lorenzleutgeb

plugins/gradle/example-client/src/main/java/io/github/kobylynskyi/order/external/ProductServiceGraphQLClient.java

@@ -25,7 +25,6 @@
 
 import java.math.BigDecimal;
 import java.net.URI;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -61,7 +60,7 @@ public Product getProduct(String productId) throws UnableToRetrieveProductExcept
         return productMapper.map(result.productById());
     }
 
-    public List<Product> getProducts(Collection<String> productIds) throws UnableToRetrieveProductsException {
+    public List<Product> getProducts(List<String> productIds) throws UnableToRetrieveProductsException {
         ProductsByIdsQueryRequest getProductRequest = new ProductsByIdsQueryRequest();
         getProductRequest.setIds(productIds);
         ProductResponseProjection responseProjection = new ProductResponseProjection()

plugins/gradle/example-client/src/main/java/io/github/kobylynskyi/order/graphql/resolvers/QueriesResolver.java

@@ -10,7 +10,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
-import java.util.Collection;
+import java.util.List;
 
 import static java.util.stream.Collectors.toList;
 
@@ -23,7 +23,7 @@ public class QueriesResolver implements OrdersQueryResolver, OrderByIdQueryResol
     private OrderMapper mapper;
 
     @Override
-    public Collection<OrderTO> orders() {
+    public List<OrderTO> orders() {
         return service.getOrders().stream().map(mapper::map).collect(toList());
     }
 

plugins/gradle/example-server/src/main/java/io/github/kobylynskyi/product/graphql/resolvers/QueriesResolver.java

@@ -9,7 +9,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
-import java.util.Collection;
+import java.util.List;
 
 import static java.util.stream.Collectors.toList;
 
@@ -22,7 +22,7 @@ public class QueriesResolver implements ProductsQueryResolver, ProductsByIdsQuer
     private ProductMapper mapper;
 
     @Override
-    public Collection<ProductTO> products() {
+    public List<ProductTO> products() {
         return service.findAll().stream().map(mapper::map).collect(toList());
     }
 
@@ -32,7 +32,7 @@ public ProductTO productById(String id) throws Exception {
     }
 
     @Override
-    public Collection<ProductTO> productsByIds(Collection<String> ids) {
+    public List<ProductTO> productsByIds(List<String> ids) {
         return service.findByIds(ids).stream().map(mapper::map).collect(toList());
     }
 }

plugins/maven/example-client/src/main/java/io/github/kobylynskyi/order/external/ProductServiceGraphQLClient.java

@@ -25,7 +25,6 @@
 
 import java.math.BigDecimal;
 import java.net.URI;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -61,7 +60,7 @@ public Product getProduct(String productId) throws UnableToRetrieveProductExcept
         return productMapper.map(result.productById());
     }
 
-    public List<Product> getProducts(Collection<String> productIds) throws UnableToRetrieveProductsException {
+    public List<Product> getProducts(List<String> productIds) throws UnableToRetrieveProductsException {
         ProductsByIdsQueryRequest getProductRequest = new ProductsByIdsQueryRequest();
         getProductRequest.setIds(productIds);
         ProductResponseProjection responseProjection = new ProductResponseProjection()

plugins/maven/example-client/src/main/java/io/github/kobylynskyi/order/graphql/resolvers/QueriesResolver.java

@@ -10,7 +10,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
-import java.util.Collection;
+import java.util.List;
 
 import static java.util.stream.Collectors.toList;
 
@@ -23,7 +23,7 @@ public class QueriesResolver implements OrdersQueryResolver, OrderByIdQueryResol
     private OrderMapper mapper;
 
     @Override
-    public Collection<OrderTO> orders() {
+    public List<OrderTO> orders() {
         return service.getOrders().stream().map(mapper::map).collect(toList());
     }
 

plugins/maven/example-server/src/main/java/io/github/kobylynskyi/product/graphql/resolvers/QueriesResolver.java

@@ -9,7 +9,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 
-import java.util.Collection;
+import java.util.List;
 
 import static java.util.stream.Collectors.toList;
 
@@ -22,7 +22,7 @@ public class QueriesResolver implements ProductsQueryResolver, ProductsByIdsQuer
     private ProductMapper mapper;
 
     @Override
-    public Collection<ProductTO> products() {
+    public List<ProductTO> products() {
         return service.findAll().stream().map(mapper::map).collect(toList());
     }
 
@@ -32,7 +32,7 @@ public ProductTO productById(String id) throws Exception {
     }
 
     @Override
-    public Collection<ProductTO> productsByIds(Collection<String> ids) {
+    public List<ProductTO> productsByIds(List<String> ids) {
         return service.findByIds(ids).stream().map(mapper::map).collect(toList());
     }
 }

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

@@ -51,9 +51,9 @@ static NamedDefinition getJavaType(MappingContext mappingContext, Type graphqlTy
         } else if (graphqlType instanceof ListType) {
             NamedDefinition mappedCollectionType = getJavaType(mappingContext, ((ListType) graphqlType).getType(), name, parentTypeName);
             if (mappedCollectionType.isInterface() && mappingContext.getInterfaceNames().contains(parentTypeName)) {
-                mappedCollectionType.setName(wrapSuperTypeIntoJavaCollection(mappedCollectionType.getName()));
+                mappedCollectionType.setName(wrapSuperTypeIntoJavaList(mappedCollectionType.getName()));
             } else {
-                mappedCollectionType.setName(wrapIntoJavaCollection(mappedCollectionType.getName()));
+                mappedCollectionType.setName(wrapIntoJavaList(mappedCollectionType.getName()));
             }
             return mappedCollectionType;
         } else if (graphqlType instanceof NonNullType) {
@@ -145,24 +145,24 @@ private static List<String> getAnnotations(MappingContext mappingContext, String
     }
 
     /**
-     * Wrap java type into collection. E.g.: "String" becomes "Collection<String"
+     * Wrap Java type into {@link java.util.List}. E.g.: {@code "String"} becomes {@code "List<String>"}
      *
-     * @param type Anything that will be wrapped into Collection<>
-     * @return String wrapped into Collection<>
+     * @param type The name of a type that will be wrapped into List<>
+     * @return String The name of the given type, wrapped into List<>
      */
-    private static String wrapIntoJavaCollection(String type) {
-        return String.format("java.util.Collection<%s>", type);
+    private static String wrapIntoJavaList(String type) {
+        return String.format("java.util.List<%s>", type);
     }
 
     /**
      * Return upper bounded wildcard for the given interface type:
-     * <code>Foo</code> becomes <code>Collection<? extends Foo></code>
+     * {@code "Foo"} becomes {@code "List<? extends Foo>"}.
      *
-     * @param type Anything that will be wrapped into Collection<? extends @type>
-     * @return String wrapped into Collection<? extends @type>
+     * @param type The name of a type whose upper bound wildcard will be wrapped into a list.
+     * @return String The name of the the wrapped type.
      */
-    private static String wrapSuperTypeIntoJavaCollection(String type) {
-        return String.format("java.util.Collection<? extends %s>", type);
+    private static String wrapSuperTypeIntoJavaList(String type) {
+        return String.format("java.util.List<? extends %s>", type);
     }
 
     /**

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

@@ -179,7 +179,7 @@ void generate_CustomSubscriptionReturnType() throws Exception {
         File[] files = Objects.requireNonNull(outputJavaClassesDir.listFiles());
 
         assertFileContainsElements(files, "EventsCreatedSubscriptionResolver.java",
-                "org.reactivestreams.Publisher<java.util.Collection<Event>> eventsCreated() throws Exception;");
+                "org.reactivestreams.Publisher<java.util.List<Event>> eventsCreated() throws Exception;");
     }
 
     @Test
@@ -345,7 +345,7 @@ void generate_AsyncQueryApis() throws Exception {
                 "java.util.concurrent.CompletableFuture<String> version()");
 
         assertFileContainsElements(files, "EventsByCategoryAndStatusQueryResolver.java",
-                "java.util.concurrent.CompletableFuture<java.util.Collection<Event>> eventsByCategoryAndStatus(");
+                "java.util.concurrent.CompletableFuture<java.util.List<Event>> eventsByCategoryAndStatus(");
 
         assertFileContainsElements(files, "EventByIdQueryResolver.java",
                 "java.util.concurrent.CompletableFuture<Event> eventById(");

src/test/resources/expected-classes/CommitResolver.java.txt

@@ -15,7 +15,7 @@ public interface CommitResolver {
     @javax.validation.constraints.NotNull
     CommitCommentConnection comments(Commit commit, String after, String before, Integer first, Integer last, graphql.schema.DataFetchingEnvironment env) throws Exception;
 
-    DeploymentConnection deployments(Commit commit, String after, String before, java.util.Collection<String> environments, Integer first, Integer last, DeploymentOrder orderBy, graphql.schema.DataFetchingEnvironment env) throws Exception;
+    DeploymentConnection deployments(Commit commit, String after, String before, java.util.List<String> environments, Integer first, Integer last, DeploymentOrder orderBy, graphql.schema.DataFetchingEnvironment env) throws Exception;
 
     @javax.validation.constraints.NotNull
     CommitHistoryConnection history(Commit commit, String after, CommitAuthor author, String before, Integer first, Integer last, String path, String since, String until, graphql.schema.DataFetchingEnvironment env) throws Exception;

src/test/resources/expected-classes/Event.java.txt

@@ -8,7 +8,7 @@ public class Event implements java.io.Serializable {
 
     private String id;
     private String categoryId;
-    private java.util.Collection<EventProperty> properties;
+    private java.util.List<EventProperty> properties;
     private EventStatus status;
     private String createdBy;
     private String createdDateTime;
@@ -18,7 +18,7 @@ public class Event implements java.io.Serializable {
     public Event() {
     }
 
-    public Event(String id, String categoryId, java.util.Collection<EventProperty> properties, EventStatus status, String createdBy, String createdDateTime, Boolean active, Integer rating) {
+    public Event(String id, String categoryId, java.util.List<EventProperty> properties, EventStatus status, String createdBy, String createdDateTime, Boolean active, Integer rating) {
         this.id = id;
         this.categoryId = categoryId;
         this.properties = properties;
@@ -43,10 +43,10 @@ public class Event implements java.io.Serializable {
         this.categoryId = categoryId;
     }
 
-    public java.util.Collection<EventProperty> getProperties() {
+    public java.util.List<EventProperty> getProperties() {
         return properties;
     }
-    public void setProperties(java.util.Collection<EventProperty> properties) {
+    public void setProperties(java.util.List<EventProperty> properties) {
         this.properties = properties;
     }
 
@@ -95,7 +95,7 @@ public class Event implements java.io.Serializable {
 
         private String id;
         private String categoryId;
-        private java.util.Collection<EventProperty> properties;
+        private java.util.List<EventProperty> properties;
         private EventStatus status;
         private String createdBy;
         private String createdDateTime;
@@ -115,7 +115,7 @@ public class Event implements java.io.Serializable {
             return this;
         }
 
-        public Builder setProperties(java.util.Collection<EventProperty> properties) {
+        public Builder setProperties(java.util.List<EventProperty> properties) {
             this.properties = properties;
             return this;
         }