[Fix serverlessworkflow#1091] Add EmittedEventDecorator (serverlessworkflow#1092)

Signed-off-by: fjtirado <[email protected]>

Author: fjtirado

impl/core/src/main/java/io/serverlessworkflow/impl/events/EmittedEventDecorator.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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 io.serverlessworkflow.impl.events;
+
+import io.cloudevents.core.builder.CloudEventBuilder;
+import io.serverlessworkflow.impl.ServicePriority;
+import io.serverlessworkflow.impl.TaskContext;
+import io.serverlessworkflow.impl.WorkflowContext;
+
+public interface EmittedEventDecorator extends ServicePriority {
+
+  void decorate(
+      CloudEventBuilder ceBuilder, WorkflowContext workflowContext, TaskContext taskContext);
+}

impl/core/src/main/java/io/serverlessworkflow/impl/executors/EmitExecutor.java

@@ -33,17 +33,24 @@
 import io.serverlessworkflow.impl.WorkflowUtils;
 import io.serverlessworkflow.impl.WorkflowValueResolver;
 import io.serverlessworkflow.impl.events.CloudEventUtils;
+import io.serverlessworkflow.impl.events.EmittedEventDecorator;
 import io.serverlessworkflow.impl.events.EventPublisher;
 import io.serverlessworkflow.impl.expressions.ExpressionDescriptor;
 import java.net.URI;
 import java.time.OffsetDateTime;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Optional;
+import java.util.ServiceLoader;
 import java.util.concurrent.CompletableFuture;
 
 public class EmitExecutor extends RegularTaskExecutor<EmitTask> {
 
+  private static final Collection<EmittedEventDecorator> emittedDecorators =
+      ServiceLoader.load(EmittedEventDecorator.class).stream()
+          .map(ServiceLoader.Provider::get)
+          .sorted()
+          .toList();
   private final EventPropertiesBuilder props;
 
   public static class EmitExecutorBuilder extends RegularTaskExecutorBuilder<EmitTask> {
@@ -124,7 +131,7 @@ private CloudEvent buildCloudEvent(WorkflowContext workflow, TaskContext taskCon
         .additionalFilter()
         .map(filter -> filter.apply(workflow, taskContext, taskContext.input()))
         .ifPresent(value -> value.forEach((k, v) -> addExtension(ceBuilder, k, v)));
-
+    emittedDecorators.forEach(d -> d.decorate(ceBuilder, workflow, taskContext));
     return ceBuilder.build();
   }