Sonar fixes

Critical smells `o.s.i.m*`.

Author: garyrussell

spring-integration-core/src/main/java/org/springframework/integration/gateway/MessagingGatewaySupport.java

@@ -507,6 +507,7 @@ private Object doSendAndReceive(Object object, boolean shouldConvert) {
 			else {
 				requestMessage = (object instanceof Message<?>)
 						? (Message<?>) object : this.requestMapper.toMessage(object);
+				Assert.state(requestMessage != null, () -> "request mapper resulted in no message for " + object);
 				requestMessage = this.historyWritingPostProcessor.postProcessMessage(requestMessage);
 				reply = this.messagingTemplate.sendAndReceive(requestChannel, requestMessage);
 				if (reply instanceof ErrorMessage) {

spring-integration-core/src/main/java/org/springframework/integration/mapping/BytesMessageMapper.java

@@ -16,6 +16,12 @@
 
 package org.springframework.integration.mapping;
 
+import java.util.Map;
+
+import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
+import org.springframework.messaging.Message;
+
 /**
  * An {@link OutboundMessageMapper} and {@link InboundMessageMapper} that
  * maps to/from {@code byte[]}.
@@ -26,4 +32,14 @@
  */
 public interface BytesMessageMapper extends InboundMessageMapper<byte[]>, OutboundMessageMapper<byte[]> {
 
+	@Override
+	@NonNull // override
+	default Message<?> toMessage(byte[] object) {
+		return toMessage(object, null);
+	}
+
+	@Override
+	@NonNull // override
+	Message<?> toMessage(byte[] bytes, @Nullable Map<String, Object> headers);
+
 }

spring-integration-core/src/main/java/org/springframework/integration/mapping/InboundMessageMapper.java

@@ -26,6 +26,7 @@
  *
  * @author Mark Fisher
  * @author Artem Bilan
+ * @author Gary Russell
  */
 @FunctionalInterface
 public interface InboundMessageMapper<T> {
@@ -36,7 +37,8 @@ public interface InboundMessageMapper<T> {
 	 * @return the message as a result of mapping
 	 * @throws Exception the exception thrown by the underlying mapper implementation
 	 */
-	default Message<?> toMessage(T object) throws Exception {
+	@Nullable
+	default Message<?> toMessage(T object) throws Exception { // NOSONAR - TODO remove Exception in 5.2
 		return toMessage(object, null);
 	}
 
@@ -50,6 +52,6 @@ default Message<?> toMessage(T object) throws Exception {
 	 * @since 5.0
 	 */
 	@Nullable
-	Message<?> toMessage(T object, @Nullable Map<String, Object> headers) throws Exception;
+	Message<?> toMessage(T object, @Nullable Map<String, Object> headers) throws Exception; // NOSONAR
 
 }

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

@@ -16,6 +16,7 @@
 
 package org.springframework.integration.support.json;
 
+import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.Collection;
@@ -229,11 +230,12 @@ public Message<?> toMessage(byte[] bytes, @Nullable Map<String, Object> headers)
 			return message;
 		}
 		else {
-			return new GenericMessage<>(bytes, headers);
+			return headers == null ? new GenericMessage<>(bytes) : new GenericMessage<>(bytes, headers);
 		}
 	}
 
-	private Message<?> decodeNativeFormat(byte[] bytes, Map<String, Object> headersToAdd) throws Exception {
+	@Nullable
+	private Message<?> decodeNativeFormat(byte[] bytes, @Nullable Map<String, Object> headersToAdd) throws IOException {
 		ByteBuffer buffer = ByteBuffer.wrap(bytes);
 		if (buffer.remaining() > 4) {
 			int headersLen = buffer.getInt();

spring-integration-jmx/src/main/java/org/springframework/integration/monitor/IntegrationMBeanExporter.java

@@ -846,9 +846,6 @@ private Object extractTarget(Object bean) {
 			return bean;
 		}
 		Advised advised = (Advised) bean;
-		if (advised.getTargetSource() == null) {
-			return null;
-		}
 		try {
 			return extractTarget(advised.getTargetSource().getTarget());
 		}
@@ -1075,7 +1072,7 @@ private MessageSourceMetrics enhanceSourceMonitor(MessageSourceMetrics monitor)
 			if (target instanceof MessagingGatewaySupport) {
 				outputChannel = ((MessagingGatewaySupport) target).getRequestChannel();
 			}
-			else {
+			else if (target instanceof SourcePollingChannelAdapter) {
 				outputChannel = ((SourcePollingChannelAdapter) target).getOutputChannel();
 			}
 

spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/AbstractConfigurableMongoDbMessageStore.java

@@ -201,7 +201,7 @@ protected int getNextId() {
 				new Update().inc(MessageDocumentFields.SEQUENCE, 1),
 				FindAndModifyOptions.options().returnNew(true).upsert(true),
 				Map.class, this.collectionName)
-				.get(MessageDocumentFields.SEQUENCE);
+					.get(MessageDocumentFields.SEQUENCE); // NOSONAR - never returns null
 	}
 
 	protected void addMessageDocument(final MessageDocument document) {

spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/store/MongoDbMessageStore.java

@@ -473,16 +473,22 @@ private int getNextId() {
 				new Update().inc(SEQUENCE, 1),
 				FindAndModifyOptions.options().returnNew(true).upsert(true),
 				Map.class,
-				this.collectionName).get(SEQUENCE);
+				this.collectionName).get(SEQUENCE); // NOSONAR - never returns null
 	}
 
 	@SuppressWarnings("unchecked")
 	private static void enhanceHeaders(MessageHeaders messageHeaders, Map<String, Object> headers) {
 		Map<String, Object> innerMap =
 				(Map<String, Object>) new DirectFieldAccessor(messageHeaders).getPropertyValue("headers");
 		// using reflection to set ID and TIMESTAMP since they are immutable through MessageHeaders
-		innerMap.put(MessageHeaders.ID, headers.get(MessageHeaders.ID));
-		innerMap.put(MessageHeaders.TIMESTAMP, headers.get(MessageHeaders.TIMESTAMP));
+		Object idHeader = headers.get(MessageHeaders.ID);
+		if (idHeader != null) {
+			innerMap.put(MessageHeaders.ID, idHeader);
+		}
+		Object tsHeader = headers.get(MessageHeaders.TIMESTAMP);
+		if (tsHeader != null) {
+			innerMap.put(MessageHeaders.TIMESTAMP, tsHeader);
+		}
 	}
 
 	@SuppressWarnings("unchecked")
@@ -760,7 +766,7 @@ public ErrorMessage convert(Document source) {
 					MongoDbMessageStore.this.converter.normalizeHeaders((Map<String, Object>) source.get("headers"));
 
 			Object payload = this.deserializingConverter.convert(((Binary) source.get("payload")).getData());
-			ErrorMessage message = new ErrorMessage((Throwable) payload, headers);
+			ErrorMessage message = new ErrorMessage((Throwable) payload, headers); // NOSONAR not null
 			enhanceHeaders(message.getHeaders(), headers);
 
 			return message;

spring-integration-mongodb/src/main/java/org/springframework/integration/mongodb/support/MongoDbMessageBytesConverter.java

@@ -59,6 +59,9 @@ public Set<ConvertiblePair> getConvertibleTypes() {
 
 	@Override
 	public Object convert(Object source, TypeDescriptor sourceType, TypeDescriptor targetType) {
+		if (source == null) {
+			return null;
+		}
 		if (Message.class.isAssignableFrom(sourceType.getObjectType())) {
 			return new Binary(this.serializingConverter.convert(source));
 		}