Include event type in visitor name

This commit fixes event visitor method generation by including the *event type*
in the visitor name. Note that event type here is actually the member name in
the encompassing eventstream structure, *not* the Java class of the event.

For example, in the example below, "Foo" is the event type.

"MyEventStream": {
   "type": "structure",
   "eventstream": true,
   "members": {
       "Foo": {
           "shape": "Bar"
       }
   }
}

To ensure that this change is backwards compatible with existing services that
have event streams (Transcribe Streaming and Kinesis), we also include a
customization to supress this behavior keep the method name as "visit".

Note that by sheer luck, the existing consumer method setters, e.g.

Builder onSubscribeToShardEvent(Consumer<SubscribeToShardEvent>);

are unaffected by this change. The previous generation scheme for these methods
is "on{Generation Java class name for event shape}"; now it's "on{event type}".
However, both Transcribe and Kinesis use the shape name as the member name (or
vise versa?) in their current iteration of their event streams.

For example, in Kinesis, SubscribeToShard's output stream is defined as

"SubscribeToShardEventStream":{
  "type":"structure",
  "required":["SubscribeToShardEvent"],
  "members":{
    "SubscribeToShardEvent":{"shape":"SubscribeToShardEvent"},

    ...
    },
  "eventstream":true
}

Author: dagnir

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

@@ -33,7 +33,8 @@ public static CodegenCustomizationProcessor getProcessorFor(
                 new ShapeModifiersProcessor(config.getShapeModifiers()),
                 new ShapeSubstitutionsProcessor(config.getShapeSubstitutions()),
                 new OperationModifiersProcessor(config.getOperationModifiers()),
-                new RemoveExceptionMessagePropertyProcessor()
+                new RemoveExceptionMessagePropertyProcessor(),
+                new ExcludeEventNameFromVisitMethodProcessor()
         );
     }
 }

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

@@ -0,0 +1,87 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.codegen.customization.processors;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import software.amazon.awssdk.codegen.customization.CodegenCustomizationProcessor;
+import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
+import software.amazon.awssdk.codegen.model.intermediate.MemberModel;
+import software.amazon.awssdk.codegen.model.intermediate.ShapeModel;
+import software.amazon.awssdk.codegen.model.service.ServiceModel;
+
+/**
+ * This process enforces constraints placed on the "excludeEventNameFromVisitMethod"; 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);
+
+    @Override
+    public void preprocess(ServiceModel serviceModel) {
+        // no-op
+    }
+
+    @Override
+    public void postprocess(IntermediateModel intermediateModel) {
+        Map<String, List<String>> excludeEventNameFromVisitMethod = intermediateModel.getCustomizationConfig()
+                .getExcludeEventNameFromVisitMethod();
+
+        excludeEventNameFromVisitMethod.forEach((eventStream, members) -> {
+            ShapeModel shapeModel = getShapeByC2jName(intermediateModel, eventStream);
+
+            if (shapeModel == null || !shapeModel.isEventStream()) {
+                log.warn("Encountered " + CUSTOMIZATION_NAME + " for unrecognized eventstream " + eventStream);
+                return;
+            }
+
+            Map<String, Integer> shapeToEventCount = new HashMap<>();
+
+            members.forEach(m -> {
+                MemberModel event = shapeModel.getMemberByC2jName(m);
+
+                if (event != null) {
+                    String shapeName = event.getC2jShape();
+                    int count = shapeToEventCount.getOrDefault(shapeName, 0);
+                    shapeToEventCount.put(shapeName, ++count);
+                } else {
+                    String msg = String.format("Encountered %s customization for unrecognized eventstream member %s#%s",
+                            CUSTOMIZATION_NAME, eventStream, m);
+                    log.warn(msg);
+                }
+            });
+
+            shapeToEventCount.forEach((shape, count) -> {
+                if (count > 1) {
+                    throw new IllegalArgumentException(CUSTOMIZATION_NAME + " customization declared for "
+                            + eventStream + ", but more than it targets more than one member with the shape " + shape);
+                }
+            });
+        });
+    }
+
+    private ShapeModel getShapeByC2jName(IntermediateModel intermediateModel, String c2jName) {
+        return intermediateModel.getShapes().values().stream()
+                .filter(s -> s.getC2jName().equals(c2jName))
+                .findAny()
+                .orElse(null);
+    }
+}

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

@@ -176,6 +176,16 @@ 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>)}.
+     * <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 CustomizationConfig() {
     }
 
@@ -454,4 +464,12 @@ public void setAllowEndpointOverrideForEndpointDiscoveryRequiredOperations(
         this.allowEndpointOverrideForEndpointDiscoveryRequiredOperations =
             allowEndpointOverrideForEndpointDiscoveryRequiredOperations;
     }
+
+    public Map<String, List<String>> getExcludeEventNameFromVisitMethod() {
+        return excludeEventNameFromVisitMethod;
+    }
+
+    public void setExcludeEventNameFromVisitMethod(Map<String, List<String>> excludeEventNameFromVisitMethod) {
+        this.excludeEventNameFromVisitMethod = excludeEventNameFromVisitMethod;
+    }
 }

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

@@ -23,6 +23,7 @@
 import software.amazon.awssdk.annotations.SdkPublicApi;
 import software.amazon.awssdk.awscore.eventstream.EventStreamResponseHandler;
 import software.amazon.awssdk.codegen.emitters.GeneratorTaskParams;
+import software.amazon.awssdk.codegen.model.intermediate.IntermediateModel;
 import software.amazon.awssdk.codegen.model.intermediate.OperationModel;
 import software.amazon.awssdk.codegen.poet.ClassSpec;
 import software.amazon.awssdk.codegen.poet.PoetExtensions;
@@ -33,6 +34,7 @@
  */
 public class EventStreamResponseHandlerSpec implements ClassSpec {
 
+    private final IntermediateModel intermediateModel;
     private final PoetExtensions poetExt;
     private final OperationModel operationModel;
     private final String apiName;
@@ -41,6 +43,7 @@ public class EventStreamResponseHandlerSpec implements ClassSpec {
     private final ClassName eventStreamBaseClass;
 
     public EventStreamResponseHandlerSpec(GeneratorTaskParams params, OperationModel operationModel) {
+        this.intermediateModel = params.getModel();
         this.poetExt = params.getPoetExtensions();
         this.operationModel = operationModel;
         this.apiName = poetExt.getApiName(operationModel);
@@ -61,7 +64,7 @@ public TypeSpec poetSpec() {
                         .addJavadoc("Response handler for the $L API.", apiName)
                         .addMethod(builderMethodSpec())
                         .addType(new EventStreamResponseHandlerBuilderInterfaceSpec(poetExt, operationModel).poetSpec())
-                        .addType(new EventStreamVisitorInterfaceSpec(poetExt, operationModel).poetSpec())
+                        .addType(new EventStreamVisitorInterfaceSpec(intermediateModel, poetExt, operationModel).poetSpec())
                         .build();
     }
 

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

@@ -96,11 +96,11 @@ public static Optional<ShapeModel> getBaseEventStreamShape(IntermediateModel mod
     }
 
     /**
-     * Returns the stream of event member shapes ('event: true') excluding exceptions
+     * Returns the stream of event members ('event: true') excluding exceptions
      * from the input event stream shape ('eventstream: true').
      */
-    public static Stream<ShapeModel> getEvents(ShapeModel eventStreamShape) {
-        return getEventMembers(eventStreamShape).map(MemberModel::getShape);
+    public static Stream<MemberModel> getEvents(ShapeModel eventStreamShape) {
+        return getEventMembers(eventStreamShape);
     }
 
     /**

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

@@ -25,16 +25,17 @@
 import javax.lang.model.element.Modifier;
 import software.amazon.awssdk.annotations.SdkInternalApi;
 import software.amazon.awssdk.codegen.emitters.GeneratorTaskParams;
+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;
 
 /**
  * Generates the implementation for the builder of an event stream visitor.
  */
 public class EventStreamVisitorBuilderImplSpec extends EventStreamVisitorBuilderInterfaceSpec {
-
+    private final IntermediateModel intermediateModel;
     private final PoetExtensions poetExt;
     private final OperationModel opModel;
     private final ClassName visitorType;
@@ -43,6 +44,7 @@ public class EventStreamVisitorBuilderImplSpec extends EventStreamVisitorBuilder
 
     public EventStreamVisitorBuilderImplSpec(GeneratorTaskParams params, OperationModel operationModel) {
         super(params.getPoetExtensions(), operationModel);
+        this.intermediateModel = params.getModel();
         this.poetExt = params.getPoetExtensions();
         this.opModel = operationModel;
         this.visitorType = poetExt.eventStreamResponseHandlerVisitorType(opModel);
@@ -68,7 +70,7 @@ private class VisitorFromBuilderImplSpec extends EventStreamVisitorInterfaceSpec
         private final MethodSpec.Builder constrBuilder;
 
         VisitorFromBuilderImplSpec() {
-            super(poetExt, opModel);
+            super(intermediateModel, poetExt, opModel);
             this.constrBuilder = MethodSpec.constructorBuilder()
                                            .addParameter(enclosingClassName(), "builder")
                                            .addStatement("this.onDefault = builder.onDefault != null ?\n"
@@ -98,10 +100,10 @@ protected MethodSpec.Builder applyVisitDefaultMethodSpecUpdates(MethodSpec.Build
         @Override
         protected MethodSpec.Builder applyVisitSubTypeMethodSpecUpdates(TypeSpec.Builder typeBuilder,
                                                                         MethodSpec.Builder methodBuilder,
-                                                                        ShapeModel s) {
-            ClassName eventSubType = poetExt.getModelClass(s.getShapeName());
+                                                                        MemberModel event) {
+            ClassName eventSubType = poetExt.getModelClass(event.getShape().getShapeName());
             TypeName eventConsumerType = consumerType(eventSubType);
-            FieldSpec consumerField = FieldSpec.builder(eventConsumerType, "on" + eventSubType.simpleName())
+            FieldSpec consumerField = FieldSpec.builder(eventConsumerType, eventConsumerName(event))
                                                .addModifiers(Modifier.PRIVATE, Modifier.FINAL)
                                                .build();
             typeBuilder.addField(consumerField);
@@ -127,10 +129,10 @@ private ClassName enclosingClassName() {
     @Override
     protected MethodSpec.Builder applyOnSubTypeMethodSpecUpdates(TypeSpec.Builder typeBuilder,
                                                                  MethodSpec.Builder methodBuilder,
-                                                                 ShapeModel eventSubTypeShape) {
-        ClassName eventSubType = poetExt.getModelClass(eventSubTypeShape.getShapeName());
+                                                                 MemberModel event) {
+        ClassName eventSubType = poetExt.getModelClass(event.getShape().getShapeName());
         TypeName eventConsumerType = consumerType(eventSubType);
-        FieldSpec consumerField = FieldSpec.builder(eventConsumerType, "on" + eventSubType.simpleName())
+        FieldSpec consumerField = FieldSpec.builder(eventConsumerType, eventConsumerName(event))
                                            .addModifiers(Modifier.PRIVATE)
                                            .build();
         typeBuilder.addField(consumerField);

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

@@ -23,11 +23,13 @@
 import java.util.function.Consumer;
 import javax.lang.model.element.Modifier;
 import software.amazon.awssdk.codegen.docs.DocumentationBuilder;
+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.ClassSpec;
 import software.amazon.awssdk.codegen.poet.PoetExtensions;
 import software.amazon.awssdk.codegen.poet.PoetUtils;
+import software.amazon.awssdk.utils.internal.CodegenNamingUtils;
 
 /**
  * Spec for builder interface for visitor.
@@ -52,8 +54,8 @@ public final TypeSpec poetSpec() {
             .addMethod(applyBuildMethodSpecUpdates(createBuildMethodSpec()).build());
 
         EventStreamUtils.getEvents(eventStreamShape)
-                        .forEach(s -> typeBuilder.addMethod(
-                            applyOnSubTypeMethodSpecUpdates(typeBuilder, createOnSubTypeMethodSpec(s), s)
+                        .forEach(e -> typeBuilder.addMethod(
+                            applyOnSubTypeMethodSpecUpdates(typeBuilder, createOnSubTypeMethodSpec(e), e)
                                 .build()));
 
         return typeBuilder.build();
@@ -105,8 +107,8 @@ protected MethodSpec.Builder applyBuildMethodSpecUpdates(MethodSpec.Builder buil
 
     protected MethodSpec.Builder applyOnSubTypeMethodSpecUpdates(TypeSpec.Builder typeBuilder,
                                                                  MethodSpec.Builder methodBuilder,
-                                                                 ShapeModel eventSubTypeShape) {
-        ClassName eventSubType = poetExt.getModelClass(eventSubTypeShape.getShapeName());
+                                                                 MemberModel event) {
+        ClassName eventSubType = poetExt.getModelClass(event.getShape().getShapeName());
         String javadocs = new DocumentationBuilder()
             .description("Callback to invoke when a {@link $T} is visited.")
             .param("c", "Callback to process the event.")
@@ -116,13 +118,16 @@ protected MethodSpec.Builder applyOnSubTypeMethodSpecUpdates(TypeSpec.Builder ty
                             .addJavadoc(javadocs, eventSubType);
     }
 
-    private MethodSpec.Builder createOnSubTypeMethodSpec(ShapeModel eventSubTypeShape) {
-        ClassName eventSubType = poetExt.getModelClass(eventSubTypeShape.getShapeName());
+    private MethodSpec.Builder createOnSubTypeMethodSpec(MemberModel event) {
+        ClassName eventSubType = poetExt.getModelClass(event.getShape().getShapeName());
         ParameterizedTypeName eventConsumerType = ParameterizedTypeName.get(ClassName.get(Consumer.class), eventSubType);
-        return MethodSpec.methodBuilder("on" + eventSubType.simpleName())
+        return MethodSpec.methodBuilder(eventConsumerName(event))
                          .addModifiers(Modifier.PUBLIC)
                          .addParameter(ParameterSpec.builder(eventConsumerType, "c").build())
                          .returns(visitorBuilderType);
     }
 
+    protected final String eventConsumerName(MemberModel event) {
+        return "on" + CodegenNamingUtils.pascalCase(event.getName());
+    }
 }