GH-422 GH-606 Add support for simplifying message headers to attribute mapping

Added CloudEventAttributesProvider and default implementation
Added CloudEventMessageUtils

spring-cloud-function-samples/function-sample-cloudevent/src/main/java/io/spring/cloudevent/CloudeventDemoApplication.java

@@ -20,8 +20,12 @@ import java.util.function.Function;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.function.cloudevent.CloudEventAttributes;
+import org.springframework.cloud.function.cloudevent.CloudEventAtttributesProvider;
+import org.springframework.cloud.function.cloudevent.DefaultCloudEventAttributesProvider;
 import org.springframework.context.annotation.Bean;
 import org.springframework.messaging.Message;
+import org.springframework.messaging.support.MessageBuilder;
 
 /**
  * Sample application that demonstrates how user functions can be triggered by cloud event.
@@ -77,4 +81,38 @@ public class CloudeventDemoApplication {
 			return v.toString();
 		};
 	}
+
+	@Bean
+	public Function<Message<SpringReleaseEvent>, Message<SpringReleaseEvent>> consumeAndProduceCloudEvent(CloudEventAtttributesProvider ceAttrProvider) {
+		return ceMessage -> {
+			SpringReleaseEvent data = ceMessage.getPayload();
+			data.setVersion("2.0");
+			data.setReleaseDateAsString("01-10-2006");
+
+			CloudEventAttributes ceAttributes = ceAttrProvider.get(ceMessage.getHeaders())
+				.setSource("https://interface21.icom/")
+				.setType("com.interface21");
+
+			return MessageBuilder.withPayload(data).copyHeaders(ceAttributes).build();
+		};
+	}
+
+//	// spring.io/applicationName
+//
+//	@Bean
+//	public Function<Message<SpringReleaseEvent>, SpringReleaseEvent> consumeAndProduceCloudEvent() {
+//		return ceMessage -> {
+//			SpringReleaseEvent data = ceMessage.getPayload();
+//			data.setVersion("2.0");
+//			data.setReleaseDateAsString("01-10-2006");
+//
+//			CloudEventAtttributesProvider ceAttrProvider = new DefaultCloudEventAttributesProvider();
+//
+//			CloudEventAttributes ceAttributes = ceAttrProvider.get(ceMessage.getHeaders())
+//				.setSource("https://interface21.icom/")
+//				.setType("com.interface21");
+//
+//			return MessageBuilder.withPayload(data).copyHeaders(ceAttributes).build();
+//		};
+//	}
 }

spring-cloud-function-samples/function-sample-cloudevent/src/main/java/io/spring/cloudevent/SpringReleaseEvent.java

@@ -16,6 +16,7 @@
 
 package io.spring.cloudevent;
 
+import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 
@@ -44,6 +45,15 @@ public class SpringReleaseEvent {
 		this.releaseDate = releaseDate;
 	}
 
+	public void setReleaseDateAsString(String releaseDate) {
+		try {
+			this.releaseDate = new SimpleDateFormat("dd-MM-yyyy").parse(releaseDate);
+		}
+		catch (ParseException e) {
+			throw new IllegalArgumentException(e);
+		}
+	}
+
 	public String getReleaseName() {
 		return releaseName;
 	}