* Fix RouterTests for proper mapping order

* Polishing for `AbstractMappingMessageRouter` hierarchy, so we don't
use `protected channelMappings` field access any more

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/router/AbstractMappingMessageRouter.java

@@ -68,13 +68,13 @@ protected boolean removeEldestEntry(Entry<String, MessageChannel> eldest) {
 
 					});
 
-	protected volatile Map<String, String> channelMappings = new LinkedHashMap<>();
+	private String prefix;
 
-	private volatile String prefix;
+	private String suffix;
 
-	private volatile String suffix;
+	private boolean resolutionRequired = true;
 
-	private volatile boolean resolutionRequired = true;
+	private volatile Map<String, String> channelMappings = new LinkedHashMap<>();
 
 
 	/**
@@ -228,9 +228,6 @@ private MessageChannel resolveChannelForName(String channelName, Message<?> mess
 				throw new MessagingException(message, "failed to resolve channel name '" + channelName + "'", e);
 			}
 		}
-		if (channel == null && this.resolutionRequired) {
-			throw new MessagingException(message, "failed to resolve channel name '" + channelName + "'");
-		}
 		return channel;
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/router/ErrorMessageExceptionTypeRouter.java

@@ -101,13 +101,13 @@ public void removeChannelMapping(String key) {
 	@ManagedOperation
 	public void replaceChannelMappings(Properties channelMappings) {
 		super.replaceChannelMappings(channelMappings);
-		populateClassNameMapping(this.channelMappings.keySet());
+		populateClassNameMapping(getChannelMappings().keySet());
 	}
 
 	@Override
 	protected void onInit() {
 		super.onInit();
-		populateClassNameMapping(this.channelMappings.keySet());
+		populateClassNameMapping(getChannelMappings().keySet());
 		this.initialized = true;
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/router/PayloadTypeRouter.java

@@ -16,21 +16,21 @@
 
 package org.springframework.integration.router;
 
-import java.util.ArrayList;
 import java.util.Collections;
+import java.util.LinkedList;
 import java.util.List;
 
 import org.springframework.messaging.Message;
 import org.springframework.util.CollectionUtils;
 
 /**
  * A Message Router that resolves the {@link org.springframework.messaging.MessageChannel}
- * based on the
- * {@link Message Message's} payload type.
+ * based on the {@link Message Message's} payload type.
  *
  * @author Mark Fisher
  * @author Oleg Zhurakousky
  * @author Gary Russell
+ * @author Artem Bilan
  */
 public class PayloadTypeRouter extends AbstractMappingMessageRouter {
 
@@ -47,23 +47,22 @@ public class PayloadTypeRouter extends AbstractMappingMessageRouter {
 	 */
 	@Override
 	protected List<Object> getChannelKeys(Message<?> message) {
-		if (CollectionUtils.isEmpty(this.channelMappings)) {
+		if (CollectionUtils.isEmpty(getChannelMappings())) {
 			return null;
 		}
 		Class<?> type = message.getPayload().getClass();
 		boolean isArray = type.isArray();
 		if (isArray) {
 			type = type.getComponentType();
 		}
-		String closestMatch =  this.findClosestMatch(type, isArray);
-		return (closestMatch != null) ? Collections.<Object>singletonList(closestMatch) : null;
+		String closestMatch = findClosestMatch(type, isArray);
+		return (closestMatch != null) ? Collections.singletonList(closestMatch) : null;
 	}
 
-
 	private String findClosestMatch(Class<?> type, boolean isArray) {
 		int minTypeDiffWeight = Integer.MAX_VALUE;
-		List<String> matches = new ArrayList<String>();
-		for (String candidate : this.channelMappings.keySet()) {
+		List<String> matches = new LinkedList<>();
+		for (String candidate : getChannelMappings().keySet()) {
 			if (isArray) {
 				if (!candidate.endsWith(ARRAY_SUFFIX)) {
 					continue;
@@ -118,7 +117,7 @@ private int determineTypeDifferenceWeight(String candidate, Class<?> type, int l
 			// exhausted hierarchy and found no match
 			return Integer.MAX_VALUE;
 		}
-		return this.determineTypeDifferenceWeight(candidate, type.getSuperclass(), level + 2);
+		return determineTypeDifferenceWeight(candidate, type.getSuperclass(), level + 2);
 	}
 
 }

spring-integration-core/src/test/java/org/springframework/integration/dsl/routers/RouterTests.java

@@ -743,8 +743,8 @@ public IntegrationFlow payloadTypeRouteFlow() {
 		public IntegrationFlow exceptionTypeRouteFlow() {
 			return f -> f
 					.routeByException(r -> r
-							.channelMapping(IllegalArgumentException.class, "illegalArgumentChannel")
 							.channelMapping(RuntimeException.class, "runtimeExceptionChannel")
+							.channelMapping(IllegalArgumentException.class, "illegalArgumentChannel")
 							.subFlowMapping(MessageHandlingException.class, sf ->
 									sf.channel("messageHandlingExceptionChannel"))
 							.defaultOutputChannel("exceptionRouterDefaultChannel"));