Document TaskDecorator usage with TaskExecutors

Closes gh-33438

framework-docs/src/main/java/org/springframework/docs/integration/schedulingtaskexecutorusage/LoggingTaskDecorator.java

@@ -0,0 +1,36 @@
+/*
+ * 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.
+ * 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.docs.integration.schedulingtaskexecutorusage;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.core.task.TaskDecorator;
+
+public class LoggingTaskDecorator implements TaskDecorator {
+
+	private static final Log logger = LogFactory.getLog(LoggingTaskDecorator.class);
+
+	@Override
+	public Runnable decorate(Runnable runnable) {
+		return () -> {
+			logger.debug("Before execution of " + runnable);
+			runnable.run();
+			logger.debug("After execution of " + runnable);
+		};
+	}
+}

framework-docs/src/main/java/org/springframework/docs/integration/schedulingtaskexecutorusage/TaskExecutorConfiguration.java

@@ -38,4 +38,13 @@ public class TaskExecutorConfiguration {
 		return new TaskExecutorExample(taskExecutor);
 	}
 	// end::snippet[]
+
+	// tag::decorator[]
+	@Bean
+	ThreadPoolTaskExecutor decoratedTaskExecutor() {
+		ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
+		taskExecutor.setTaskDecorator(new LoggingTaskDecorator());
+		return taskExecutor;
+	}
+	// end::decorator[]
 }

framework-docs/src/main/kotlin/org/springframework/docs/integration/schedulingtaskexecutorusage/LoggingTaskDecorator.kt

@@ -0,0 +1,38 @@
+/*
+ * 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.
+ * 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.docs.integration.schedulingtaskexecutorusage
+
+import org.apache.commons.logging.Log
+import org.apache.commons.logging.LogFactory
+import org.springframework.core.task.TaskDecorator
+
+class LoggingTaskDecorator : TaskDecorator {
+
+	override fun decorate(runnable: Runnable): Runnable {
+		return Runnable {
+			logger.debug("Before execution of $runnable")
+			runnable.run()
+			logger.debug("After execution of $runnable")
+		}
+	}
+
+	companion object {
+		private val logger: Log = LogFactory.getLog(
+			LoggingTaskDecorator::class.java
+		)
+	}
+}

framework-docs/src/main/kotlin/org/springframework/docs/integration/schedulingtaskexecutorusage/TaskExecutorConfiguration.kt

@@ -34,4 +34,11 @@ class TaskExecutorConfiguration {
 	@Bean
 	fun taskExecutorExample(taskExecutor: ThreadPoolTaskExecutor) = TaskExecutorExample(taskExecutor)
 	// end::snippet[]
+
+	// tag::decorator[]
+	@Bean
+	fun decoratedTaskExecutor() = ThreadPoolTaskExecutor().apply {
+		setTaskDecorator(LoggingTaskDecorator())
+	}
+	// end::decorator[]
 }

framework-docs/src/main/resources/org/springframework/docs/integration/schedulingtaskexecutorusage/TaskExecutorConfiguration.xml

@@ -15,4 +15,13 @@
 	</bean>
 	<!-- end::snippet[] -->
 
+	<!-- tag::decorator[] -->
+	<bean id="decoratedTaskExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
+		<property name="taskDecorator" ref="loggingTaskDecorator"/>
+	</bean>
+	<!-- end::decorator[] -->
+
+	<bean id="loggingTaskDecorator" class="org.springframework.docs.integration.schedulingtaskexecutorusage.LoggingTaskDecorator">
+	</bean>
+
 </beans>