Cleanup in the Core graph package

* Mostly code style and IDEA suggestions
* Mitigate stress of NPE in the `TcpReceivingChannelAdapterTests`

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/graph/CompositeMessageHandlerNode.java

@@ -27,6 +27,7 @@
  * Represents a composite message handler.
  *
  * @author Gary Russell
+ * @author Artem Bilan
  *
  * @since 4.3
  *
@@ -35,8 +36,8 @@ public class CompositeMessageHandlerNode extends MessageHandlerNode {
 
 	private final List<InnerHandler> handlers = new ArrayList<>();
 
-	public CompositeMessageHandlerNode(int nodeId, String name, MessageHandler handler, String input, @Nullable String output,
-			List<InnerHandler> handlers) {
+	public CompositeMessageHandlerNode(int nodeId, String name, MessageHandler handler, String input,
+			@Nullable String output, List<InnerHandler> handlers) {
 
 		super(nodeId, name, handler, input, output);
 		this.handlers.addAll(handlers);
@@ -46,24 +47,7 @@ public List<InnerHandler> getHandlers() {
 		return this.handlers;
 	}
 
-	public static class InnerHandler {
-
-		private final String name;
-
-		private final String type;
-
-		public InnerHandler(String name, String type) {
-			this.name = name;
-			this.type = type;
-		}
-
-		public String getName() {
-			return this.name;
-		}
-
-		public String getType() {
-			return this.type;
-		}
+	public record InnerHandler(String name, String type) {
 
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/graph/ErrorCapableEndpointNode.java

@@ -30,7 +30,9 @@ public class ErrorCapableEndpointNode extends EndpointNode implements ErrorCapab
 
 	private final @Nullable String errors;
 
-	protected ErrorCapableEndpointNode(int nodeId, String name, Object nodeObject, @Nullable String output, @Nullable String errors) {
+	protected ErrorCapableEndpointNode(int nodeId, String name, Object nodeObject, @Nullable String output,
+			@Nullable String errors) {
+
 		super(nodeId, name, nodeObject, output);
 		this.errors = errors;
 	}

spring-integration-core/src/main/java/org/springframework/integration/graph/ErrorCapableMessageHandlerNode.java

@@ -24,6 +24,7 @@
  * Represents a message handler that can produce errors (pollable).
  *
  * @author Gary Russell
+ *
  * @since 4.3
  *
  */

spring-integration-core/src/main/java/org/springframework/integration/graph/ErrorCapableRoutingNode.java

@@ -35,8 +35,8 @@ public class ErrorCapableRoutingNode extends RoutingMessageHandlerNode implement
 
 	private final @Nullable String errors;
 
-	public ErrorCapableRoutingNode(int nodeId, String name, MessageHandler handler, String input, @Nullable String output,
-			@Nullable String errors, Collection<String> routes) {
+	public ErrorCapableRoutingNode(int nodeId, String name, MessageHandler handler, String input,
+			@Nullable String output, @Nullable String errors, Collection<String> routes) {
 
 		super(nodeId, name, handler, input, output, routes);
 		this.errors = errors;

spring-integration-core/src/main/java/org/springframework/integration/graph/Graph.java

@@ -20,39 +20,22 @@
 import java.util.Map;
 
 /**
- * This object can be exposed, for example, as a JSON object over
- * HTTP.
+ * This object can be exposed, for example, as a JSON object over HTTP.
+ *
+ * @param contentDescriptor the Spring Integration application attributes.
+ * @param nodes the Spring Integration application endpoints.
+ * @param links the Spring Integration application message channels between endpoints.
  *
  * @author Andy Clement
  * @author Gary Russell
+ * @author Artem Bilan
  *
  * @since 4.3
  *
  */
-public class Graph {
-
-	private final Map<String, Object> contentDescriptor;
-
-	private final Collection<IntegrationNode> nodes;
-
-	private final Collection<LinkNode> links;
-
-	public Graph(Map<String, Object> descriptor, Collection<IntegrationNode> nodes, Collection<LinkNode> links) {
-		this.contentDescriptor = descriptor;
-		this.nodes = nodes;
-		this.links = links;
-	}
-
-	public Map<String, Object> getContentDescriptor() {
-		return this.contentDescriptor;
-	}
-
-	public Collection<IntegrationNode> getNodes() {
-		return this.nodes;
-	}
-
-	public Collection<LinkNode> getLinks() {
-		return this.links;
-	}
+public record Graph(
+		Map<String, Object> contentDescriptor,
+		Collection<IntegrationNode> nodes,
+		Collection<LinkNode> links) {
 
 }

spring-integration-core/src/main/java/org/springframework/integration/graph/IntegrationGraphServer.java

@@ -67,6 +67,7 @@
  * @author Gary Russell
  * @author Artem Bilan
  * @author Christian Tzolov
+ * @author Glenn Renfro
  *
  * @since 4.3
  *

spring-integration-core/src/main/java/org/springframework/integration/graph/IntegrationNode.java

@@ -49,8 +49,7 @@ public abstract class IntegrationNode {
 
 	private final String componentType;
 
-	@Nullable
-	private final IntegrationPatternType integrationPatternType;
+	private final @Nullable IntegrationPatternType integrationPatternType;
 
 	private final IntegrationPatternType.@Nullable IntegrationPatternCategory integrationPatternCategory;
 
@@ -115,8 +114,7 @@ public final String getComponentType() {
 		return this.componentType;
 	}
 
-	@Nullable
-	public IntegrationPatternType getIntegrationPatternType() {
+	public @Nullable IntegrationPatternType getIntegrationPatternType() {
 		return this.integrationPatternType;
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/graph/LinkNode.java

@@ -19,35 +19,17 @@
 /**
  * Represents a link between nodes.
  *
+ * @param from the source node index
+ * @param to the target node index
+ * @param type the {@link Type} of this link
+ *
  * @author Gary Russell
+ * @author Artem Bilan
+ *
  * @since 4.3
  *
  */
-public class LinkNode {
-
-	private final int from;
-
-	private final int to;
-
-	private final Type type;
-
-	public LinkNode(int from, int to, Type type) {
-		this.from = from;
-		this.to = to;
-		this.type = type;
-	}
-
-	public int getFrom() {
-		return this.from;
-	}
-
-	public int getTo() {
-		return this.to;
-	}
-
-	public Type getType() {
-		return this.type;
-	}
+public record LinkNode(int from, int to, Type type) {
 
 	public enum Type {
 		input, output, error, discard, route

spring-integration-core/src/main/java/org/springframework/integration/graph/MessageGatewayNode.java

@@ -16,6 +16,8 @@
 
 package org.springframework.integration.graph;
 
+import java.util.function.Supplier;
+
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.gateway.MessagingGatewaySupport;
@@ -24,14 +26,28 @@
  * Represents an inbound gateway.
  *
  * @author Gary Russell
+ * @author Artem Bilan
  *
  * @since 4.3
  *
  */
-public class MessageGatewayNode extends ErrorCapableEndpointNode {
+public class MessageGatewayNode extends ErrorCapableEndpointNode implements SendTimersAware {
+
+	private @Nullable Supplier<SendTimers> sendTimers;
+
+	public MessageGatewayNode(int nodeId, String name, MessagingGatewaySupport gateway, @Nullable String output,
+			@Nullable String errors) {
 
-	public MessageGatewayNode(int nodeId, String name, MessagingGatewaySupport gateway, @Nullable String output, @Nullable String errors) {
 		super(nodeId, name, gateway, output, errors);
 	}
 
+	@Override
+	public void sendTimers(Supplier<SendTimers> timers) {
+		this.sendTimers = timers;
+	}
+
+	public @Nullable SendTimers getSendTimers() {
+		return this.sendTimers != null ? this.sendTimers.get() : null;
+	}
+
 }

spring-integration-core/src/main/java/org/springframework/integration/graph/MessageProducerNode.java

@@ -16,6 +16,8 @@
 
 package org.springframework.integration.graph;
 
+import java.util.function.Supplier;
+
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.endpoint.MessageProducerSupport;
@@ -24,14 +26,28 @@
  * Represents an inbound message producer.
  *
  * @author Gary Russell
+ * @author Artem Bilan
  *
  * @since 4.3
  *
  */
-public class MessageProducerNode extends ErrorCapableEndpointNode {
+public class MessageProducerNode extends ErrorCapableEndpointNode implements SendTimersAware {
+
+	private @Nullable Supplier<SendTimers> sendTimers;
+
+	public MessageProducerNode(int nodeId, String name, MessageProducerSupport producer, String output,
+			@Nullable String errors) {
 
-	public MessageProducerNode(int nodeId, String name, MessageProducerSupport producer, String output, @Nullable String errors) {
 		super(nodeId, name, producer, output, errors);
 	}
 
+	@Override
+	public void sendTimers(Supplier<SendTimers> timers) {
+		this.sendTimers = timers;
+	}
+
+	public @Nullable SendTimers getSendTimers() {
+		return this.sendTimers != null ? this.sendTimers.get() : null;
+	}
+
 }