GH-9416: Extract BaseMessageBuilder for easier message extensions

Fixes: #9416
Issue link: https://github.com/spring-projects/spring-integration/issues/9416

The `MessageBuilderFactory` bean could be used a central place to provide custom `Message`
implementation into the application.
For example, the `GenericMessage.toString()` can be overridden to remove or mask sensitive
information from the payload or headers.

* Extract a `BaseMessageBuilder` from the `MessageBuilder` class to simplify
a custom `MessageBuilderFactory` implementation
* Test and document new feature and its purpose

spring-integration-core/src/main/java/org/springframework/integration/IntegrationMessageHeaderAccessor.java

@@ -108,7 +108,7 @@ public class IntegrationMessageHeaderAccessor extends MessageHeaderAccessor {
 	 * @see #isReadOnly(String)
 	 */
 	public void setReadOnlyHeaders(String... readOnlyHeaders) {
-		Assert.noNullElements(readOnlyHeaders, "'readOnlyHeaders' must not be contain null items.");
+		Assert.noNullElements(readOnlyHeaders, "'readOnlyHeaders' must not contain null items.");
 		if (!ObjectUtils.isEmpty(readOnlyHeaders)) {
 			this.readOnlyHeaders = new HashSet<>(Arrays.asList(readOnlyHeaders));
 		}

spring-integration-core/src/main/java/org/springframework/integration/support/BaseMessageBuilder.java

@@ -0,0 +1,335 @@
+/*
+ * Copyright 2024 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
+ *
+ *      https://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.integration.support;
+
+import java.util.Arrays;
+import java.util.Date;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.integration.IntegrationMessageHeaderAccessor;
+import org.springframework.lang.Nullable;
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.messaging.MessageHeaders;
+import org.springframework.messaging.support.ErrorMessage;
+import org.springframework.messaging.support.GenericMessage;
+import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
+
+/**
+ * The {@link AbstractIntegrationMessageBuilder} extension for the default logic to build message.
+ * The {@link MessageBuilder} is fully based on this class.
+ * This abstract class can be used for creating custom {@link Message} instances.
+ * For that purpose its {@link #build()} method has to be overridden.
+ * The custom {@link Message} type could be used, for example, to hide sensitive information
+ * from payload and headers when message is logged.
+ * For this goal there would be enough to override {@link GenericMessage#toString()}
+ * and filter out (or mask) those headers which container such sensitive information.
+ *
+ * @param <T> the payload type.
+ * @param <B> the target builder class type.
+ *
+ * @author Artem Bilan
+ *
+ * @since 6.4
+ *
+ * @see MessageBuilder
+ * @see MessageBuilderFactory
+ */
+public abstract class BaseMessageBuilder<T, B extends BaseMessageBuilder<T, B>>
+		extends AbstractIntegrationMessageBuilder<T> {
+
+	private static final Log LOGGER = LogFactory.getLog(BaseMessageBuilder.class);
+
+	private final T payload;
+
+	private final IntegrationMessageHeaderAccessor headerAccessor;
+
+	@Nullable
+	private final Message<T> originalMessage;
+
+	private volatile boolean modified;
+
+	private String[] readOnlyHeaders;
+
+	protected BaseMessageBuilder(T payload, @Nullable Message<T> originalMessage) {
+		Assert.notNull(payload, "payload must not be null");
+		this.payload = payload;
+		this.originalMessage = originalMessage;
+		this.headerAccessor = new IntegrationMessageHeaderAccessor(originalMessage);
+		if (originalMessage != null) {
+			this.modified = (!this.payload.equals(originalMessage.getPayload()));
+		}
+	}
+
+	@Override
+	public T getPayload() {
+		return this.payload;
+	}
+
+	@Override
+	public Map<String, Object> getHeaders() {
+		return this.headerAccessor.toMap();
+	}
+
+	@Nullable
+	@Override
+	public <V> V getHeader(String key, Class<V> type) {
+		return this.headerAccessor.getHeader(key, type);
+	}
+
+	/**
+	 * Set the value for the given header name. If the provided value is {@code null}, the header will be removed.
+	 * @param headerName The header name.
+	 * @param headerValue The header value.
+	 * @return this MessageBuilder.
+	 */
+	@Override
+	public B setHeader(String headerName, @Nullable Object headerValue) {
+		this.headerAccessor.setHeader(headerName, headerValue);
+		return _this();
+	}
+
+	/**
+	 * Set the value for the given header name only if the header name is not already associated with a value.
+	 * @param headerName The header name.
+	 * @param headerValue The header value.
+	 * @return this MessageBuilder.
+	 */
+	@Override
+	public B setHeaderIfAbsent(String headerName, Object headerValue) {
+		this.headerAccessor.setHeaderIfAbsent(headerName, headerValue);
+		return _this();
+	}
+
+	/**
+	 * Removes all headers provided via array of 'headerPatterns'. As the name suggests the array
+	 * may contain simple matching patterns for header names. Supported pattern styles are:
+	 * {@code xxx*}, {@code *xxx}, {@code *xxx*} and {@code xxx*yyy}.
+	 * @param headerPatterns The header patterns.
+	 * @return this MessageBuilder.
+	 */
+	@Override
+	public B removeHeaders(String... headerPatterns) {
+		this.headerAccessor.removeHeaders(headerPatterns);
+		return _this();
+	}
+
+	/**
+	 * Remove the value for the given header name.
+	 * @param headerName The header name.
+	 * @return this MessageBuilder.
+	 */
+	@Override
+	public B removeHeader(String headerName) {
+		if (!this.headerAccessor.isReadOnly(headerName)) {
+			this.headerAccessor.removeHeader(headerName);
+		}
+		else if (LOGGER.isInfoEnabled()) {
+			LOGGER.info("The header [" + headerName + "] is ignored for removal because it is is readOnly.");
+		}
+		return _this();
+	}
+
+	/**
+	 * Copy the name-value pairs from the provided Map. This operation will overwrite any existing values. Use
+	 * {@link #copyHeadersIfAbsent(Map)} to avoid overwriting values. Note that the 'id' and 'timestamp' header values
+	 * will never be overwritten.
+	 * @param headersToCopy The headers to copy.
+	 * @return this MessageBuilder.
+	 * @see MessageHeaders#ID
+	 * @see MessageHeaders#TIMESTAMP
+	 */
+	@Override
+	public B copyHeaders(@Nullable Map<String, ?> headersToCopy) {
+		this.headerAccessor.copyHeaders(headersToCopy);
+		return _this();
+	}
+
+	/**
+	 * Copy the name-value pairs from the provided Map. This operation will not override any existing values.
+	 * @param headersToCopy The headers to copy.
+	 * @return this MessageBuilder.
+	 */
+	@Override
+	public B copyHeadersIfAbsent(@Nullable Map<String, ?> headersToCopy) {
+		if (headersToCopy != null) {
+			for (Map.Entry<String, ?> entry : headersToCopy.entrySet()) {
+				String headerName = entry.getKey();
+				if (!this.headerAccessor.isReadOnly(headerName)) {
+					this.headerAccessor.setHeaderIfAbsent(headerName, entry.getValue());
+				}
+			}
+		}
+		return _this();
+	}
+
+	@SuppressWarnings("unchecked")
+	@Override
+	@Nullable
+	protected List<List<Object>> getSequenceDetails() {
+		return (List<List<Object>>) this.headerAccessor.getHeader(IntegrationMessageHeaderAccessor.SEQUENCE_DETAILS);
+	}
+
+	@Override
+	@Nullable
+	protected Object getCorrelationId() {
+		return this.headerAccessor.getCorrelationId();
+	}
+
+	@Override
+	protected Object getSequenceNumber() {
+		return this.headerAccessor.getSequenceNumber();
+	}
+
+	@Override
+	protected Object getSequenceSize() {
+		return this.headerAccessor.getSequenceSize();
+	}
+
+	@Override
+	public B pushSequenceDetails(Object correlationId, int sequenceNumber, int sequenceSize) {
+		super.pushSequenceDetails(correlationId, sequenceNumber, sequenceSize);
+		return _this();
+	}
+
+	@Override
+	public B popSequenceDetails() {
+		super.popSequenceDetails();
+		return _this();
+	}
+
+	@Override
+	public B setExpirationDate(@Nullable Long expirationDate) {
+		super.setExpirationDate(expirationDate);
+		return _this();
+	}
+
+	@Override
+	public B setExpirationDate(@Nullable Date expirationDate) {
+		super.setExpirationDate(expirationDate);
+		return _this();
+	}
+
+	@Override
+	public B setCorrelationId(Object correlationId) {
+		super.setCorrelationId(correlationId);
+		return _this();
+	}
+
+	@Override
+	public B setReplyChannel(MessageChannel replyChannel) {
+		super.setReplyChannel(replyChannel);
+		return _this();
+	}
+
+	@Override
+	public B setReplyChannelName(String replyChannelName) {
+		super.setReplyChannelName(replyChannelName);
+		return _this();
+	}
+
+	@Override
+	public B setErrorChannel(MessageChannel errorChannel) {
+		super.setErrorChannel(errorChannel);
+		return _this();
+	}
+
+	@Override
+	public B setErrorChannelName(String errorChannelName) {
+		super.setErrorChannelName(errorChannelName);
+		return _this();
+	}
+
+	@Override
+	public B setSequenceNumber(Integer sequenceNumber) {
+		super.setSequenceNumber(sequenceNumber);
+		return _this();
+	}
+
+	@Override
+	public B setSequenceSize(Integer sequenceSize) {
+		super.setSequenceSize(sequenceSize);
+		return _this();
+	}
+
+	@Override
+	public B setPriority(Integer priority) {
+		super.setPriority(priority);
+		return _this();
+	}
+
+	/**
+	 * Specify a list of headers which should be considered as read only
+	 * and prohibited from being populated in the message.
+	 * @param readOnlyHeaders the list of headers for {@code readOnly} mode.
+	 * Defaults to {@link MessageHeaders#ID} and {@link MessageHeaders#TIMESTAMP}.
+	 * @return the current {@link BaseMessageBuilder}
+	 * @see IntegrationMessageHeaderAccessor#isReadOnly(String)
+	 */
+	public B readOnlyHeaders(@Nullable String... readOnlyHeaders) {
+		this.readOnlyHeaders = readOnlyHeaders != null ? Arrays.copyOf(readOnlyHeaders, readOnlyHeaders.length) : null;
+		if (readOnlyHeaders != null) {
+			this.headerAccessor.setReadOnlyHeaders(readOnlyHeaders);
+		}
+		return _this();
+	}
+
+	/**
+	 * Return an original message instance if it is not modified and does not have read-only headers.
+	 * If payload is an instance of {@link Throwable}, then an {@link ErrorMessage} is built.
+	 * Otherwise, a new instance of {@link GenericMessage} is produced.
+	 * This method can be overridden to provide any custom message implementations.
+	 * @return the message instance
+	 * @see #getPayload()
+	 * @see #getHeaders()
+	 */
+	@Override
+	@SuppressWarnings("unchecked")
+	public Message<T> build() {
+		if (!this.modified && !this.headerAccessor.isModified() && this.originalMessage != null
+				&& !containsReadOnly(this.originalMessage.getHeaders())) {
+
+			return this.originalMessage;
+		}
+		if (payload instanceof Throwable throwable) {
+			return (Message<T>) new ErrorMessage(throwable, getHeaders());
+		}
+		return new GenericMessage<>(payload, getHeaders());
+	}
+
+	private boolean containsReadOnly(MessageHeaders headers) {
+		if (!ObjectUtils.isEmpty(this.readOnlyHeaders)) {
+			for (String readOnly : this.readOnlyHeaders) {
+				if (headers.containsKey(readOnly)) {
+					return true;
+				}
+			}
+		}
+		return false;
+	}
+
+	@SuppressWarnings("unchecked")
+	private B _this() {
+		return (B) this;
+	}
+
+}

spring-integration-core/src/main/java/org/springframework/integration/support/MessageBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -16,23 +16,10 @@
 
 package org.springframework.integration.support;
 
-import java.util.Arrays;
-import java.util.Date;
-import java.util.List;
-import java.util.Map;
-
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-
-import org.springframework.integration.IntegrationMessageHeaderAccessor;
 import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
-import org.springframework.messaging.MessageChannel;
-import org.springframework.messaging.MessageHeaders;
-import org.springframework.messaging.support.ErrorMessage;
 import org.springframework.messaging.support.GenericMessage;
 import org.springframework.util.Assert;
-import org.springframework.util.ObjectUtils;
 
 /**
  * The default message builder; creates immutable {@link GenericMessage}s.
@@ -48,52 +35,17 @@ import org.springframework.util.ObjectUtils;
  * @author Gary Russell
  * @author Artem Bilan
  */
-public final class MessageBuilder<T> extends AbstractIntegrationMessageBuilder<T> {
-
-	private static final Log LOGGER = LogFactory.getLog(MessageBuilder.class);
-
-	private final T payload;
-
-	private final IntegrationMessageHeaderAccessor headerAccessor;
-
-	@Nullable
-	private final Message<T> originalMessage;
-
-	private volatile boolean modified;
-
-	private String[] readOnlyHeaders;
+public final class MessageBuilder<T> extends BaseMessageBuilder<T, MessageBuilder<T>> {
 
 	/**
 	 * Private constructor to be invoked from the static factory methods only.
 	 */
 	private MessageBuilder(T payload, @Nullable Message<T> originalMessage) {
-		Assert.notNull(payload, "payload must not be null");
-		this.payload = payload;
-		this.originalMessage = originalMessage;
-		this.headerAccessor = new IntegrationMessageHeaderAccessor(originalMessage);
-		if (originalMessage != null) {
-			this.modified = (!this.payload.equals(originalMessage.getPayload()));
-		}
-	}
-
-	@Override
-	public T getPayload() {
-		return this.payload;
-	}
-
-	@Override
-	public Map<String, Object> getHeaders() {
-		return this.headerAccessor.toMap();
-	}
-
-	@Nullable
-	@Override
-	public <V> V getHeader(String key, Class<V> type) {
-		return this.headerAccessor.getHeader(key, type);
+		super(payload, originalMessage);
 	}
 
 	/**
-	 * Create a builder for a new {@link Message} instance pre-populated with all of the headers copied from the
+	 * Create a builder for a new {@link Message} instance pre-populated with all the headers copied from the
 	 * provided message. The payload of the provided Message will also be used as the payload for the new message.
 	 * @param message the Message from which the payload and all headers will be copied
 	 * @param <T> The type of the payload.
@@ -114,230 +66,4 @@ public final class MessageBuilder<T> extends AbstractIntegrationMessageBuilder<T
 		return new MessageBuilder<>(payload, null);
 	}
 
-	/**
-	 * Set the value for the given header name. If the provided value is <code>null</code>, the header will be removed.
-	 * @param headerName The header name.
-	 * @param headerValue The header value.
-	 * @return this MessageBuilder.
-	 */
-	@Override
-	public MessageBuilder<T> setHeader(String headerName, @Nullable Object headerValue) {
-		this.headerAccessor.setHeader(headerName, headerValue);
-		return this;
-	}
-
-	/**
-	 * Set the value for the given header name only if the header name is not already associated with a value.
-	 * @param headerName The header name.
-	 * @param headerValue The header value.
-	 * @return this MessageBuilder.
-	 */
-	@Override
-	public MessageBuilder<T> setHeaderIfAbsent(String headerName, Object headerValue) {
-		this.headerAccessor.setHeaderIfAbsent(headerName, headerValue);
-		return this;
-	}
-
-	/**
-	 * Removes all headers provided via array of 'headerPatterns'. As the name suggests the array
-	 * may contain simple matching patterns for header names. Supported pattern styles are:
-	 * "xxx*", "*xxx", "*xxx*" and "xxx*yyy".
-	 * @param headerPatterns The header patterns.
-	 * @return this MessageBuilder.
-	 */
-	@Override
-	public MessageBuilder<T> removeHeaders(String... headerPatterns) {
-		this.headerAccessor.removeHeaders(headerPatterns);
-		return this;
-	}
-
-	/**
-	 * Remove the value for the given header name.
-	 * @param headerName The header name.
-	 * @return this MessageBuilder.
-	 */
-	@Override
-	public MessageBuilder<T> removeHeader(String headerName) {
-		if (!this.headerAccessor.isReadOnly(headerName)) {
-			this.headerAccessor.removeHeader(headerName);
-		}
-		else if (LOGGER.isInfoEnabled()) {
-			LOGGER.info("The header [" + headerName + "] is ignored for removal because it is is readOnly.");
-		}
-		return this;
-	}
-
-	/**
-	 * Copy the name-value pairs from the provided Map. This operation will overwrite any existing values. Use {
-	 * {@link #copyHeadersIfAbsent(Map)} to avoid overwriting values. Note that the 'id' and 'timestamp' header values
-	 * will never be overwritten.
-	 * @param headersToCopy The headers to copy.
-	 * @return this MessageBuilder.
-	 * @see MessageHeaders#ID
-	 * @see MessageHeaders#TIMESTAMP
-	 */
-	@Override
-	public MessageBuilder<T> copyHeaders(@Nullable Map<String, ?> headersToCopy) {
-		this.headerAccessor.copyHeaders(headersToCopy);
-		return this;
-	}
-
-	/**
-	 * Copy the name-value pairs from the provided Map. This operation will <em>not</em> overwrite any existing values.
-	 * @param headersToCopy The headers to copy.
-	 * @return this MessageBuilder.
-	 */
-	@Override
-	public MessageBuilder<T> copyHeadersIfAbsent(@Nullable Map<String, ?> headersToCopy) {
-		if (headersToCopy != null) {
-			for (Map.Entry<String, ?> entry : headersToCopy.entrySet()) {
-				String headerName = entry.getKey();
-				if (!this.headerAccessor.isReadOnly(headerName)) {
-					this.headerAccessor.setHeaderIfAbsent(headerName, entry.getValue());
-				}
-			}
-		}
-		return this;
-	}
-
-	@SuppressWarnings("unchecked")
-	@Override
-	@Nullable
-	protected List<List<Object>> getSequenceDetails() {
-		return (List<List<Object>>) this.headerAccessor.getHeader(IntegrationMessageHeaderAccessor.SEQUENCE_DETAILS);
-	}
-
-	@Override
-	@Nullable
-	protected Object getCorrelationId() {
-		return this.headerAccessor.getCorrelationId();
-	}
-
-	@Override
-	protected Object getSequenceNumber() {
-		return this.headerAccessor.getSequenceNumber();
-	}
-
-	@Override
-	protected Object getSequenceSize() {
-		return this.headerAccessor.getSequenceSize();
-	}
-
-	/*
-	 * The following overrides (delegating to super) are provided to ease the
-	 * pain for existing applications that use the builder API and expect
-	 * a MessageBuilder to be returned.
-	 */
-	@Override
-	public MessageBuilder<T> pushSequenceDetails(Object correlationId, int sequenceNumber, int sequenceSize) {
-		super.pushSequenceDetails(correlationId, sequenceNumber, sequenceSize);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> popSequenceDetails() {
-		super.popSequenceDetails();
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setExpirationDate(@Nullable Long expirationDate) {
-		super.setExpirationDate(expirationDate);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setExpirationDate(@Nullable Date expirationDate) {
-		super.setExpirationDate(expirationDate);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setCorrelationId(Object correlationId) {
-		super.setCorrelationId(correlationId);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setReplyChannel(MessageChannel replyChannel) {
-		super.setReplyChannel(replyChannel);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setReplyChannelName(String replyChannelName) {
-		super.setReplyChannelName(replyChannelName);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setErrorChannel(MessageChannel errorChannel) {
-		super.setErrorChannel(errorChannel);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setErrorChannelName(String errorChannelName) {
-		super.setErrorChannelName(errorChannelName);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setSequenceNumber(Integer sequenceNumber) {
-		super.setSequenceNumber(sequenceNumber);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setSequenceSize(Integer sequenceSize) {
-		super.setSequenceSize(sequenceSize);
-		return this;
-	}
-
-	@Override
-	public MessageBuilder<T> setPriority(Integer priority) {
-		super.setPriority(priority);
-		return this;
-	}
-
-	/**
-	 * Specify a list of headers which should be considered as read only
-	 * and prohibited from being populated in the message.
-	 * @param readOnlyHeaders the list of headers for {@code readOnly} mode.
-	 * Defaults to {@link MessageHeaders#ID} and {@link MessageHeaders#TIMESTAMP}.
-	 * @return the current {@link MessageBuilder}
-	 * @since 4.3.2
-	 * @see IntegrationMessageHeaderAccessor#isReadOnly(String)
-	 */
-	public MessageBuilder<T> readOnlyHeaders(String... readOnlyHeaders) {
-		this.readOnlyHeaders = readOnlyHeaders != null ? Arrays.copyOf(readOnlyHeaders, readOnlyHeaders.length) : null;
-		this.headerAccessor.setReadOnlyHeaders(readOnlyHeaders);
-		return this;
-	}
-
-	@Override
-	@SuppressWarnings("unchecked")
-	public Message<T> build() {
-		if (!this.modified && !this.headerAccessor.isModified() && this.originalMessage != null
-				&& !containsReadOnly(this.originalMessage.getHeaders())) {
-
-			return this.originalMessage;
-		}
-		if (this.payload instanceof Throwable) {
-			return (Message<T>) new ErrorMessage((Throwable) this.payload, this.headerAccessor.toMap());
-		}
-		return new GenericMessage<>(this.payload, this.headerAccessor.toMap());
-	}
-
-	private boolean containsReadOnly(MessageHeaders headers) {
-		if (!ObjectUtils.isEmpty(this.readOnlyHeaders)) {
-			for (String readOnly : this.readOnlyHeaders) {
-				if (headers.containsKey(readOnly)) {
-					return true;
-				}
-			}
-		}
-		return false;
-	}
-
 }

spring-integration-core/src/test/java/org/springframework/integration/support/MessageBuilderTests.java

@@ -16,16 +16,22 @@
 
 package org.springframework.integration.support;
 
-import org.junit.Test;
+import java.io.Serial;
+import java.util.Map;
+import java.util.stream.Collectors;
 
+import org.junit.jupiter.api.Test;
+
+import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
+import org.springframework.messaging.support.GenericMessage;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
  * @author Gary Russell
+ * @author Artem Bilan
  * @since 4.3.10
- *
  */
 public class MessageBuilderTests {
 
@@ -45,4 +51,71 @@ public class MessageBuilderTests {
 		assertThat(message.getHeaders().get("qux")).isNull();
 	}
 
+	@Test
+	public void personalInfoHeadersAreMaskedWithCustomMessage() {
+		Message<String> message =
+				MessageBuilder.withPayload("some_user")
+						.setHeader("password", "some_password")
+						.build();
+
+		Message<String> piiMessage = new PiiMessageBuilderFactory().fromMessage(message).build();
+
+		assertThat(piiMessage).isInstanceOf(PiiMessage.class);
+		assertThat(piiMessage.getPayload()).isEqualTo("some_user");
+		assertThat(piiMessage.getHeaders().get("password")).isEqualTo("some_password");
+		assertThat(piiMessage.toString())
+				.doesNotContain("some_password")
+				.contains("******");
+	}
+
+	private static class PiiMessageBuilderFactory implements MessageBuilderFactory {
+
+		@Override
+		public <T> PiiMessageBuilder<T> fromMessage(Message<T> message) {
+			return new PiiMessageBuilder<>(message.getPayload(), message);
+		}
+
+		@Override
+		public <T> PiiMessageBuilder<T> withPayload(T payload) {
+			return new PiiMessageBuilder<>(payload, null);
+		}
+
+	}
+
+	private static class PiiMessageBuilder<P> extends BaseMessageBuilder<P, PiiMessageBuilder<P>> {
+
+		public PiiMessageBuilder(P payload, @Nullable Message<P> originalMessage) {
+			super(payload, originalMessage);
+		}
+
+		@Override
+		public Message<P> build() {
+			return new PiiMessage<>(getPayload(), getHeaders());
+		}
+
+	}
+
+	private static class PiiMessage<P> extends GenericMessage<P> {
+
+		@Serial
+		private static final long serialVersionUID = -354503673433669578L;
+
+		public PiiMessage(P payload, Map<String, Object> headers) {
+			super(payload, headers);
+		}
+
+		@Override
+		public String toString() {
+			return "PiiMessage [payload=" + getPayload() + ", headers=" + maskHeaders(getHeaders()) + ']';
+		}
+
+		private static Map<String, Object> maskHeaders(Map<String, Object> headers) {
+			return headers.entrySet()
+					.stream()
+					.map((entry) -> entry.getKey().equals("password") ? Map.entry(entry.getKey(), "******") : entry)
+					.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+		}
+
+	}
+
 }