Subclass events to do visitor dispatch

Generate events as discrete subclasses of the base shape class that take care
dispatching to the correct visitor method. The base shape is what we would
generate as a normal model class for a non request/response shape today.
However, because they need to be extended, they are no longer final; insteach
any method that can be made final (such as property getters) is made final.

This commit also generates static builder methods on the event stream interface
to make discovery and creation of events easier.

Author: dagnir

build-tools/src/main/resources/software/amazon/awssdk/spotbugs-suppressions.xml

@@ -211,4 +211,9 @@
         <Method name="execute"/>
         <Bug pattern="RCN_REDUNDANT_NULLCHECK_OF_NONNULL_VALUE"/>
     </Match>
+
+    <Match>
+        <Package name="~software\.amazon\.awssdk\.services\.protocolrestjson\.model\..*"/>
+        <Bug pattern="NM_SAME_SIMPLE_NAME_AS_INTERFACE, NM_SAME_SIMPLE_NAME_AS_SUPERCLASS"/>
+    </Match>
 </FindBugsFilter>

codegen/src/main/java/software/amazon/awssdk/codegen/customization/processors/DefaultCustomizationProcessor.java

@@ -34,7 +34,7 @@ public static CodegenCustomizationProcessor getProcessorFor(
                 new ShapeSubstitutionsProcessor(config.getShapeSubstitutions()),
                 new OperationModifiersProcessor(config.getOperationModifiers()),
                 new RemoveExceptionMessagePropertyProcessor(),
-                new ExcludeEventNameFromVisitMethodProcessor()
+                new UseLegacyEventGenerationSchemeProcessor()
         );
     }
 }

codegen/src/main/java/software/amazon/awssdk/codegen/customization/processors/ExcludeEventNameFromVisitMethodProcessor.java renamed to codegen/src/main/java/software/amazon/awssdk/codegen/customization/processors/UseLegacyEventGenerationSchemeProcessor.java

@@ -27,13 +27,13 @@
 import software.amazon.awssdk.codegen.model.service.ServiceModel;
 
 /**
- * This process enforces constraints placed on the "excludeEventNameFromVisitMethod"; i.e. that no two members
+ * This process enforces constraints placed on the "useLegacyEventGenerationSchemeProcessor"; i.e. that no two members
  * of the same event stream sharing the same shape have this customization enabled for them. This processor does not
  * modify the the service or intermediate model.
  */
-public class ExcludeEventNameFromVisitMethodProcessor implements CodegenCustomizationProcessor {
-    private static final String CUSTOMIZATION_NAME = "ExcludeEventNameFromVisitMethod";
-    private static final Logger log = LoggerFactory.getLogger(ExcludeEventNameFromVisitMethodProcessor.class);
+public class UseLegacyEventGenerationSchemeProcessor implements CodegenCustomizationProcessor {
+    private static final String CUSTOMIZATION_NAME = "UseLegacyEventGenerationScheme";
+    private static final Logger log = LoggerFactory.getLogger(UseLegacyEventGenerationSchemeProcessor.class);
 
     @Override
     public void preprocess(ServiceModel serviceModel) {
@@ -42,14 +42,15 @@ public void preprocess(ServiceModel serviceModel) {
 
     @Override
     public void postprocess(IntermediateModel intermediateModel) {
-        Map<String, List<String>> excludeEventNameFromVisitMethod = intermediateModel.getCustomizationConfig()
-                .getExcludeEventNameFromVisitMethod();
+        Map<String, List<String>> useLegacyEventGenerationScheme = intermediateModel.getCustomizationConfig()
+                .getUseLegacyEventGenerationScheme();
 
-        excludeEventNameFromVisitMethod.forEach((eventStream, members) -> {
+        useLegacyEventGenerationScheme.forEach((eventStream, members) -> {
             ShapeModel shapeModel = getShapeByC2jName(intermediateModel, eventStream);
 
             if (shapeModel == null || !shapeModel.isEventStream()) {
-                log.warn("Encountered " + CUSTOMIZATION_NAME + " for unrecognized eventstream " + eventStream);
+                log.warn(String.format("Encountered %s for unrecognized eventstream %s",
+                        CUSTOMIZATION_NAME, eventStream));
                 return;
             }
 

codegen/src/main/java/software/amazon/awssdk/codegen/emitters/tasks/ModelClassGeneratorTasks.java

@@ -17,12 +17,15 @@
 
 import static software.amazon.awssdk.utils.FunctionalUtils.safeFunction;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
+import java.util.stream.Collectors;
 import software.amazon.awssdk.codegen.emitters.GeneratorTask;
 import software.amazon.awssdk.codegen.emitters.GeneratorTaskParams;
 import software.amazon.awssdk.codegen.emitters.PoetGeneratorTask;
+import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
+import software.amazon.awssdk.codegen.model.intermediate.MemberModel;
 import software.amazon.awssdk.codegen.model.intermediate.Metadata;
 import software.amazon.awssdk.codegen.model.intermediate.ShapeModel;
 import software.amazon.awssdk.codegen.model.intermediate.ShapeType;
@@ -31,20 +34,23 @@
 import software.amazon.awssdk.codegen.poet.model.AwsServiceBaseRequestSpec;
 import software.amazon.awssdk.codegen.poet.model.AwsServiceBaseResponseSpec;
 import software.amazon.awssdk.codegen.poet.model.AwsServiceModel;
+import software.amazon.awssdk.codegen.poet.model.EventModelSpec;
+import software.amazon.awssdk.codegen.poet.model.EventStreamSpecHelper;
 import software.amazon.awssdk.codegen.poet.model.ResponseMetadataSpec;
 import software.amazon.awssdk.codegen.poet.model.ServiceModelCopiers;
 
 class ModelClassGeneratorTasks extends BaseGeneratorTasks {
-
     private final String modelClassDir;
+    private final IntermediateModel intermediateModel;
 
     ModelClassGeneratorTasks(GeneratorTaskParams dependencies) {
         super(dependencies);
         this.modelClassDir = dependencies.getPathProvider().getModelDirectory();
+        this.intermediateModel = dependencies.getModel();
     }
 
     @Override
-    protected List<GeneratorTask> createTasks() throws Exception {
+    protected List<GeneratorTask> createTasks() {
         List<GeneratorTask> tasks = new ArrayList<>();
 
         tasks.add(new PoetGeneratorTask(modelClassDir, model.getFileHeader(), new AwsServiceBaseRequestSpec(model)));
@@ -55,6 +61,8 @@ protected List<GeneratorTask> createTasks() throws Exception {
                     .map(safeFunction(this::createTask))
                     .forEach(tasks::add);
 
+        tasks.addAll(eventModelGenerationTasks());
+
         new ServiceModelCopiers(model).copierSpecs().stream()
                 .map(safeFunction(spec -> new PoetGeneratorTask(modelClassDir, model.getFileHeader(), spec)))
                 .forEach(tasks::add);
@@ -72,7 +80,7 @@ private boolean shouldGenerateShape(ShapeModel shapeModel) {
         return true;
     }
 
-    private GeneratorTask createTask(ShapeModel shapeModel) throws IOException {
+    private GeneratorTask createTask(ShapeModel shapeModel) {
         Metadata metadata = model.getMetadata();
         ClassSpec classSpec;
         if (shapeModel.getShapeType() == ShapeType.Enum) {
@@ -82,4 +90,25 @@ private GeneratorTask createTask(ShapeModel shapeModel) throws IOException {
         }
         return new PoetGeneratorTask(modelClassDir, model.getFileHeader(), classSpec);
     }
+
+    private List<GeneratorTask> eventModelGenerationTasks() {
+        return model.getShapes().values().stream()
+                .filter(ShapeModel::isEventStream)
+                .flatMap(eventStream -> {
+                    EventStreamSpecHelper eventStreamSpecHelper = new EventStreamSpecHelper(eventStream,
+                            intermediateModel);
+
+                    return eventStream.getMembers().stream()
+                            .filter(e -> e.getShape().isEvent())
+                            .filter(e -> !eventStreamSpecHelper.useLegacyGenerationScheme(e))
+                            .map(e -> createEventGenerationTask(e, eventStream));
+                })
+                .collect(Collectors.toList());
+    }
+
+    private GeneratorTask createEventGenerationTask(MemberModel memberModel, ShapeModel eventStream) {
+        EventModelSpec spec = new EventModelSpec(memberModel, eventStream, model);
+        String outputDir = modelClassDir + "/" + eventStream.getShapeName().toLowerCase(Locale.ENGLISH);
+        return new PoetGeneratorTask(outputDir, model.getFileHeader(), spec);
+    }
 }

codegen/src/main/java/software/amazon/awssdk/codegen/model/config/customization/CustomizationConfig.java

@@ -177,14 +177,13 @@ public class CustomizationConfig {
     private boolean allowEndpointOverrideForEndpointDiscoveryRequiredOperations = false;
 
     /**
-     * Customization to instruct the code generator *not* to include the event's name in the {@code Visitor#visit*()}
-     * method; i.e. the signature of the method will be {@code void visit(<Event Shape type>)}.
+     * Customization to instruct the code generator to use the legacy model generation scheme for the given events.
      * <p>
      * <b>NOTE</b>This customization is primarily here to preserve backwards compatibility with existing code before the
      * generation scheme for the visitor methods was changed. There should be no good reason to use this customization
      * for any other purpose.
      */
-    private Map<String, List<String>> excludeEventNameFromVisitMethod = new HashMap<>();
+    private Map<String, List<String>> useLegacyEventGenerationScheme = new HashMap<>();
 
     private CustomizationConfig() {
     }
@@ -465,11 +464,11 @@ public void setAllowEndpointOverrideForEndpointDiscoveryRequiredOperations(
             allowEndpointOverrideForEndpointDiscoveryRequiredOperations;
     }
 
-    public Map<String, List<String>> getExcludeEventNameFromVisitMethod() {
-        return excludeEventNameFromVisitMethod;
+    public Map<String, List<String>> getUseLegacyEventGenerationScheme() {
+        return useLegacyEventGenerationScheme;
     }
 
-    public void setExcludeEventNameFromVisitMethod(Map<String, List<String>> excludeEventNameFromVisitMethod) {
-        this.excludeEventNameFromVisitMethod = excludeEventNameFromVisitMethod;
+    public void setUseLegacyEventGenerationScheme(Map<String, List<String>> useLegacyEventGenerationScheme) {
+        this.useLegacyEventGenerationScheme = useLegacyEventGenerationScheme;
     }
 }

codegen/src/main/java/software/amazon/awssdk/codegen/poet/eventstream/EventStreamVisitorBuilderImplSpec.java

@@ -28,8 +28,10 @@
 import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
 import software.amazon.awssdk.codegen.model.intermediate.MemberModel;
 import software.amazon.awssdk.codegen.model.intermediate.OperationModel;
+import software.amazon.awssdk.codegen.model.intermediate.ShapeModel;
 import software.amazon.awssdk.codegen.poet.PoetExtensions;
 import software.amazon.awssdk.codegen.poet.PoetUtils;
+import software.amazon.awssdk.codegen.poet.model.EventStreamSpecHelper;
 
 /**
  * Generates the implementation for the builder of an event stream visitor.
@@ -41,6 +43,7 @@ public class EventStreamVisitorBuilderImplSpec extends EventStreamVisitorBuilder
     private final ClassName visitorType;
     private final ClassName visitorBuilderType;
     private final ClassName eventStreamBaseClass;
+    private final EventStreamSpecHelper eventStreamSpecHelper;
 
     public EventStreamVisitorBuilderImplSpec(GeneratorTaskParams params, OperationModel operationModel) {
         super(params.getPoetExtensions(), operationModel);
@@ -49,8 +52,10 @@ public EventStreamVisitorBuilderImplSpec(GeneratorTaskParams params, OperationMo
         this.opModel = operationModel;
         this.visitorType = poetExt.eventStreamResponseHandlerVisitorType(opModel);
         this.visitorBuilderType = poetExt.eventStreamResponseHandlerVisitorBuilderType(opModel);
-        this.eventStreamBaseClass = poetExt.getModelClassFromShape(
-            EventStreamUtils.getEventStreamInResponse(operationModel.getOutputShape()));
+
+        ShapeModel eventStream = EventStreamUtils.getEventStreamInResponse(operationModel.getOutputShape());
+        this.eventStreamBaseClass = poetExt.getModelClassFromShape(eventStream);
+        this.eventStreamSpecHelper = new EventStreamSpecHelper(eventStream, intermediateModel);
     }
 
     @Override
@@ -110,7 +115,8 @@ protected MethodSpec.Builder applyVisitSubTypeMethodSpecUpdates(TypeSpec.Builder
 
             constrBuilder.addStatement("this.$1L = builder.$1L != null ?\n"
                                        + "builder.$1L :\n"
-                                       + "$2T.super::visit", consumerField.name, visitorType);
+                                       + "$2T.super::$3N", consumerField.name, visitorType,
+                    eventStreamSpecHelper.visitMethodName(event));
             return methodBuilder
                 .addAnnotation(Override.class)
                 .addStatement("$L.accept(event)", consumerField.name);

codegen/src/main/java/software/amazon/awssdk/codegen/poet/eventstream/EventStreamVisitorInterfaceSpec.java

@@ -19,8 +19,6 @@
 import com.squareup.javapoet.MethodSpec;
 import com.squareup.javapoet.ParameterSpec;
 import com.squareup.javapoet.TypeSpec;
-import java.util.List;
-import java.util.Map;
 import javax.lang.model.element.Modifier;
 import software.amazon.awssdk.codegen.docs.DocumentationBuilder;
 import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
@@ -30,24 +28,24 @@
 import software.amazon.awssdk.codegen.poet.ClassSpec;
 import software.amazon.awssdk.codegen.poet.PoetExtensions;
 import software.amazon.awssdk.codegen.poet.PoetUtils;
-import software.amazon.awssdk.utils.internal.CodegenNamingUtils;
+import software.amazon.awssdk.codegen.poet.model.EventStreamSpecHelper;
 
 /**
  * Spec for generated visitor interface.
  */
 class EventStreamVisitorInterfaceSpec implements ClassSpec {
-    private final IntermediateModel intermediateModel;
     private final PoetExtensions poetExt;
     private final OperationModel operationModel;
     private final ShapeModel eventStreamShape;
     private final ClassName eventStreamBaseClass;
+    private final EventStreamSpecHelper eventStreamSpecHelper;
 
     EventStreamVisitorInterfaceSpec(IntermediateModel intermediateModel, PoetExtensions poetExt, OperationModel operationModel) {
-        this.intermediateModel = intermediateModel;
         this.poetExt = poetExt;
         this.operationModel = operationModel;
         this.eventStreamShape = EventStreamUtils.getEventStreamInResponse(operationModel.getOutputShape());
         this.eventStreamBaseClass = poetExt.getModelClassFromShape(eventStreamShape);
+        this.eventStreamSpecHelper = new EventStreamSpecHelper(eventStreamShape, intermediateModel);
     }
 
     @Override
@@ -126,10 +124,7 @@ protected MethodSpec.Builder applyVisitSubTypeMethodSpecUpdates(TypeSpec.Builder
     }
 
     protected String visitorMethodName(MemberModel event) {
-        if (!excludeNameFromVisitorName(event)) {
-            return "visit" + CodegenNamingUtils.pascalCase(event.getName());
-        }
-        return "visit";
+        return eventStreamSpecHelper.visitMethodName(event);
     }
 
     private MethodSpec createBuilderMethodSpec() {
@@ -141,17 +136,4 @@ private MethodSpec createBuilderMethodSpec() {
                          .addStatement("return new Default$LVisitorBuilder()", poetExt.getApiName(operationModel))
                          .build();
     }
-
-    private boolean excludeNameFromVisitorName(MemberModel event) {
-        Map<String, List<String>> excludeEventNameFromVisitMethod = intermediateModel.getCustomizationConfig()
-                .getExcludeEventNameFromVisitMethod();
-
-        List<String> targetEvents = excludeEventNameFromVisitMethod.get(eventStreamShape.getC2jName());
-
-        if (targetEvents == null) {
-            return false;
-        }
-
-        return targetEvents.stream().anyMatch(e -> e.equals(event.getC2jName()));
-    }
 }