Move getListenerId method to Smart/GenericApplicationListener

See gh-26638

spring-context/src/main/java/org/springframework/context/ApplicationListener.java

@@ -18,7 +18,6 @@ package org.springframework.context;
 
 import java.util.EventListener;
 import java.util.function.Consumer;
-import java.util.function.Predicate;
 
 /**
  * Interface to be implemented by application event listeners.
@@ -36,6 +35,8 @@ import java.util.function.Predicate;
  * @param <E> the specific {@code ApplicationEvent} subclass to listen to
  * @see org.springframework.context.ApplicationEvent
  * @see org.springframework.context.event.ApplicationEventMulticaster
+ * @see org.springframework.context.event.SmartApplicationListener
+ * @see org.springframework.context.event.GenericApplicationListener
  * @see org.springframework.context.event.EventListener
  */
 @FunctionalInterface
@@ -47,17 +48,6 @@ public interface ApplicationListener<E extends ApplicationEvent> extends EventLi
 	 */
 	void onApplicationEvent(E event);
 
-	/**
-	 * Return an optional identifier for the listener.
-	 * <p>The default value is an empty String.
-	 * @since 5.3.5
-	 * @see org.springframework.context.event.EventListener#id
-	 * @see org.springframework.context.event.ApplicationEventMulticaster#removeApplicationListeners(Predicate)
-	 */
-	default String getListenerId() {
-		return "";
-	}
-
 
 	/**
 	 * Create a new {@code ApplicationListener} for the given payload consumer.

spring-context/src/main/java/org/springframework/context/event/ApplicationEventMulticaster.java

@@ -78,7 +78,7 @@ public interface ApplicationEventMulticaster {
 	 * <p>Note: This just applies to instance registrations, not to listeners
 	 * registered by bean name.
 	 * @param predicate the predicate to identify listener instances to remove,
-	 * e.g. checking {@link ApplicationListener#getListenerId()}
+	 * e.g. checking {@link SmartApplicationListener#getListenerId()}
 	 * @since 5.3.5
 	 * @see #addApplicationListener(ApplicationListener)
 	 * @see #removeApplicationListener(ApplicationListener)

spring-context/src/main/java/org/springframework/context/event/GenericApplicationListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -18,9 +18,7 @@ package org.springframework.context.event;
 
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
-import org.springframework.core.Ordered;
 import org.springframework.core.ResolvableType;
-import org.springframework.lang.Nullable;
 
 /**
  * Extended variant of the standard {@link ApplicationListener} interface,
@@ -28,13 +26,26 @@ import org.springframework.lang.Nullable;
  *
  * <p>As of Spring Framework 4.2, this interface supersedes the Class-based
  * {@link SmartApplicationListener} with full handling of generic event types.
+ * As of 5.3.5, it formally extends {@link SmartApplicationListener}, adapting
+ * {@link #supportsEventType(Class)} to {@link #supportsEventType(ResolvableType)}
+ * with a default method.
  *
  * @author Stephane Nicoll
+ * @author Juergen Hoeller
  * @since 4.2
  * @see SmartApplicationListener
  * @see GenericApplicationListenerAdapter
  */
-public interface GenericApplicationListener extends ApplicationListener<ApplicationEvent>, Ordered {
+public interface GenericApplicationListener extends SmartApplicationListener {
+
+	/**
+	 * Overrides {@link SmartApplicationListener#supportsEventType(Class)} with
+	 * delegation to {@link #supportsEventType(ResolvableType)}.
+	 */
+	@Override
+	default boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
+		return supportsEventType(ResolvableType.forClass(eventType));
+	}
 
 	/**
 	 * Determine whether this listener actually supports the given event type.
@@ -42,22 +53,4 @@ public interface GenericApplicationListener extends ApplicationListener<Applicat
 	 */
 	boolean supportsEventType(ResolvableType eventType);
 
-	/**
-	 * Determine whether this listener actually supports the given source type.
-	 * <p>The default implementation always returns {@code true}.
-	 * @param sourceType the source type, or {@code null} if no source
-	 */
-	default boolean supportsSourceType(@Nullable Class<?> sourceType) {
-		return true;
-	}
-
-	/**
-	 * Determine this listener's order in a set of listeners for the same event.
-	 * <p>The default implementation returns {@link #LOWEST_PRECEDENCE}.
-	 */
-	@Override
-	default int getOrder() {
-		return LOWEST_PRECEDENCE;
-	}
-
 }

spring-context/src/main/java/org/springframework/context/event/GenericApplicationListenerAdapter.java

@@ -36,7 +36,7 @@ import org.springframework.util.ConcurrentReferenceHashMap;
  * @since 3.0
  * @see org.springframework.context.ApplicationListener#onApplicationEvent
  */
-public class GenericApplicationListenerAdapter implements GenericApplicationListener, SmartApplicationListener {
+public class GenericApplicationListenerAdapter implements GenericApplicationListener {
 
 	private static final Map<Class<?>, ResolvableType> eventTypeCache = new ConcurrentReferenceHashMap<>();
 
@@ -64,15 +64,13 @@ public class GenericApplicationListenerAdapter implements GenericApplicationList
 		this.delegate.onApplicationEvent(event);
 	}
 
-	@Override
-	public String getListenerId() {
-		return this.delegate.getListenerId();
-	}
-
 	@Override
 	@SuppressWarnings("unchecked")
 	public boolean supportsEventType(ResolvableType eventType) {
-		if (this.delegate instanceof SmartApplicationListener) {
+		if (this.delegate instanceof GenericApplicationListener) {
+			return ((GenericApplicationListener) this.delegate).supportsEventType(eventType);
+		}
+		else if (this.delegate instanceof SmartApplicationListener) {
 			Class<? extends ApplicationEvent> eventClass = (Class<? extends ApplicationEvent>) eventType.resolve();
 			return (eventClass != null && ((SmartApplicationListener) this.delegate).supportsEventType(eventClass));
 		}
@@ -81,11 +79,6 @@ public class GenericApplicationListenerAdapter implements GenericApplicationList
 		}
 	}
 
-	@Override
-	public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
-		return supportsEventType(ResolvableType.forClass(eventType));
-	}
-
 	@Override
 	public boolean supportsSourceType(@Nullable Class<?> sourceType) {
 		return !(this.delegate instanceof SmartApplicationListener) ||
@@ -97,6 +90,12 @@ public class GenericApplicationListenerAdapter implements GenericApplicationList
 		return (this.delegate instanceof Ordered ? ((Ordered) this.delegate).getOrder() : Ordered.LOWEST_PRECEDENCE);
 	}
 
+	@Override
+	public String getListenerId() {
+		return (this.delegate instanceof SmartApplicationListener ?
+				((SmartApplicationListener) this.delegate).getListenerId() : "");
+	}
+
 
 	@Nullable
 	private static ResolvableType resolveDeclaredEventType(ApplicationListener<ApplicationEvent> listener) {

spring-context/src/main/java/org/springframework/context/event/SmartApplicationListener.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -59,4 +59,15 @@ public interface SmartApplicationListener extends ApplicationListener<Applicatio
 		return LOWEST_PRECEDENCE;
 	}
 
+	/**
+	 * Return an optional identifier for the listener.
+	 * <p>The default value is an empty String.
+	 * @since 5.3.5
+	 * @see EventListener#id
+	 * @see ApplicationEventMulticaster#removeApplicationListeners
+	 */
+	default String getListenerId() {
+		return "";
+	}
+
 }

spring-context/src/main/java/org/springframework/context/event/SourceFilteringListener.java

@@ -34,7 +34,7 @@ import org.springframework.lang.Nullable;
  * @author Stephane Nicoll
  * @since 2.0.5
  */
-public class SourceFilteringListener implements GenericApplicationListener, SmartApplicationListener {
+public class SourceFilteringListener implements GenericApplicationListener {
 
 	private final Object source;
 
@@ -74,21 +74,11 @@ public class SourceFilteringListener implements GenericApplicationListener, Smar
 		}
 	}
 
-	@Override
-	public String getListenerId() {
-		return (this.delegate != null ? this.delegate.getListenerId() : "");
-	}
-
 	@Override
 	public boolean supportsEventType(ResolvableType eventType) {
 		return (this.delegate == null || this.delegate.supportsEventType(eventType));
 	}
 
-	@Override
-	public boolean supportsEventType(Class<? extends ApplicationEvent> eventType) {
-		return supportsEventType(ResolvableType.forType(eventType));
-	}
-
 	@Override
 	public boolean supportsSourceType(@Nullable Class<?> sourceType) {
 		return (sourceType != null && sourceType.isInstance(this.source));
@@ -99,6 +89,11 @@ public class SourceFilteringListener implements GenericApplicationListener, Smar
 		return (this.delegate != null ? this.delegate.getOrder() : Ordered.LOWEST_PRECEDENCE);
 	}
 
+	@Override
+	public String getListenerId() {
+		return (this.delegate != null ? this.delegate.getListenerId() : "");
+	}
+
 
 	/**
 	 * Actually process the event, after having filtered according to the