Add originalMessage to ErrorMessage

Issue: SPR-15459

spring-messaging/src/main/java/org/springframework/messaging/support/ErrorMessage.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,13 +18,23 @@ package org.springframework.messaging.support;
 
 import java.util.Map;
 
+import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 
 /**
  * A {@link GenericMessage} with a {@link Throwable} payload.
+ * The payload is typically a {@link org.springframework.messaging.MessagingException}
+ * with the message at the point of failure in its {@code failedMessage} property.
+ * An optional {@code originalMessage} may be provided, which represents the message
+ * that existed at the point in the stack where the error message is created.
+ * <p>Consider some code that starts with a message, invokes some process that performs
+ * transformation on that message and then fails for some reason, throwing the exception.
+ * The exception is caught and an error message produced that contains both the original
+ * message, and the transformed message that failed.
  *
  * @author Mark Fisher
  * @author Oleg Zhurakousky
+ * @author Gary Russell
  * @since 4.0
  * @see MessageBuilder
  */
@@ -32,6 +42,7 @@ public class ErrorMessage extends GenericMessage<Throwable> {
 
 	private static final long serialVersionUID = -5470210965279837728L;
 
+	private final Message<?> originalMessage;
 
 	/**
 	 * Create a new message with the given payload.
@@ -39,6 +50,7 @@ public class ErrorMessage extends GenericMessage<Throwable> {
 	 */
 	public ErrorMessage(Throwable payload) {
 		super(payload);
+		this.originalMessage = null;
 	}
 
 	/**
@@ -49,6 +61,7 @@ public class ErrorMessage extends GenericMessage<Throwable> {
 	 */
 	public ErrorMessage(Throwable payload, Map<String, Object> headers) {
 		super(payload, headers);
+		this.originalMessage = null;
 	}
 
 	/**
@@ -60,6 +73,72 @@ public class ErrorMessage extends GenericMessage<Throwable> {
 	 */
 	public ErrorMessage(Throwable payload, MessageHeaders headers) {
 		super(payload, headers);
+		this.originalMessage = null;
+	}
+
+	/**
+	 * Create a new message with the given payload and original message.
+	 * @param payload the message payload (never {@code null})
+	 * @param originalMessage the original message (if present) at the point in the stack
+	 *        where the ErrorMessage was created
+	 * @since 5.0
+	 */
+	public ErrorMessage(Throwable payload, Message<?> originalMessage) {
+		super(payload);
+		this.originalMessage = originalMessage;
+	}
+
+	/**
+	 * Create a new message with the given payload, headers and original message.
+	 * The content of the given header map is copied.
+	 * @param payload the message payload (never {@code null})
+	 * @param headers message headers to use for initialization
+	 * @param originalMessage the original message (if present) at the point in the stack
+	 *        where the ErrorMessage was created
+	 * @since 5.0
+	 */
+	public ErrorMessage(Throwable payload, Map<String, Object> headers, Message<?> originalMessage) {
+		super(payload, headers);
+		this.originalMessage = originalMessage;
+	}
+
+	/**
+	 * Create a new message with the payload, {@link MessageHeaders} and original message.
+	 * <p><strong>Note:</strong> the given {@code MessageHeaders} instance
+	 * is used directly in the new message, i.e. it is not copied.
+	 * @param payload the message payload (never {@code null})
+	 * @param headers message headers
+	 * @param originalMessage the original message (if present) at the point in the stack
+	 *        where the ErrorMessage was created
+	 * @since 5.0
+	 */
+	public ErrorMessage(Throwable payload, MessageHeaders headers, Message<?> originalMessage) {
+		super(payload, headers);
+		this.originalMessage = originalMessage;
+	}
+
+	/**
+	 * The original message (if present) at the point in the stack where the
+	 * ErrorMessage was created.
+	 * @return the originalMessage
+	 */
+	public Message<?> getOriginalMessage() {
+		return originalMessage;
+	}
+
+	@Override
+	public String toString() {
+		if (this.originalMessage == null) {
+			return super.toString();
+		}
+		else {
+			StringBuilder sb = new StringBuilder(super.toString());
+			if (sb.length() > 0) {
+				sb.setLength(sb.length() - 1);
+			}
+			sb.append(", originalMessage=").append(this.originalMessage.toString()).append("]");
+			return sb.toString();
+		}
 	}
 
 }

spring-messaging/src/test/java/org/springframework/messaging/support/ErrorMessageTests.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2017 the original author or 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 org.springframework.messaging.support;
+
+import org.junit.Test;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
+/**
+ *
+ * @author Gary Russell
+ * @since 5.0
+ */
+public class ErrorMessageTests {
+
+	@Test
+	public void testToString() {
+		ErrorMessage em = new ErrorMessage(new RuntimeException("foo"));
+		String emString = em.toString();
+		assertThat(emString, not(containsString("originalMessage")));
+		em = new ErrorMessage(new RuntimeException("foo"), new GenericMessage<>("bar"));
+		emString = em.toString();
+		assertThat(emString, containsString("}, originalMessage="));
+	}
+
+}