@Scheduled supports "-" as cron expression value for disabled triggers

Issue: SPR-16858

spring-context/src/main/java/org/springframework/scheduling/annotation/Scheduled.java

@@ -41,6 +41,7 @@ import java.lang.annotation.Target;
  * <em>composed annotations</em> with attribute overrides.
  *
  * @author Mark Fisher
+ * @author Juergen Hoeller
  * @author Dave Syer
  * @author Chris Beams
  * @since 3.0
@@ -55,10 +56,21 @@ import java.lang.annotation.Target;
 public @interface Scheduled {
 
 	/**
-	 * A cron-like expression, extending the usual UN*X definition to include
-	 * triggers on the second as well as minute, hour, day of month, month
-	 * and day of week.  e.g. {@code "0 * * * * MON-FRI"} means once per minute on
-	 * weekdays (at the top of the minute - the 0th second).
+	 * A special cron expression value that indicates a disabled trigger: {@value}.
+	 * <p>This is primarily meant for use with ${...} placeholders, allowing for
+	 * external disabling of corresponding scheduled methods.
+	 * @since 5.1
+	 */
+	String CRON_DISABLED = "-";
+
+
+	/**
+	 * A cron-like expression, extending the usual UN*X definition to include triggers
+	 * on the second as well as minute, hour, day of month, month and day of week.
+	 * <p>E.g. {@code "0 * * * * MON-FRI"} means once per minute on weekdays
+	 * (at the top of the minute - the 0th second).
+	 * <p>The special value {@link #CRON_DISABLED "-"} indicates a disabled cron trigger,
+	 * primarily meant for externally specified values resolved by a ${...} placeholder.
 	 * @return an expression that can be parsed to a cron schedule
 	 * @see org.springframework.scheduling.support.CronSequenceGenerator
 	 */

spring-context/src/main/java/org/springframework/scheduling/annotation/ScheduledAnnotationBeanPostProcessor.java

@@ -105,7 +105,7 @@ public class ScheduledAnnotationBeanPostProcessor
 		SmartInitializingSingleton, ApplicationListener<ContextRefreshedEvent>, DisposableBean {
 
 	/**
-	 * The default name of the {@link TaskScheduler} bean to pick up: "taskScheduler".
+	 * The default name of the {@link TaskScheduler} bean to pick up: {@value}.
 	 * <p>Note that the initial lookup happens by type; this is just the fallback
 	 * in case of multiple scheduler beans found in the context.
 	 * @since 4.2
@@ -405,14 +405,16 @@ public class ScheduledAnnotationBeanPostProcessor
 				if (StringUtils.hasLength(cron)) {
 					Assert.isTrue(initialDelay == -1, "'initialDelay' not supported for cron triggers");
 					processedSchedule = true;
-					TimeZone timeZone;
-					if (StringUtils.hasText(zone)) {
-						timeZone = StringUtils.parseTimeZoneString(zone);
-					}
-					else {
-						timeZone = TimeZone.getDefault();
+					if (!Scheduled.CRON_DISABLED.equals(cron)) {
+						TimeZone timeZone;
+						if (StringUtils.hasText(zone)) {
+							timeZone = StringUtils.parseTimeZoneString(zone);
+						}
+						else {
+							timeZone = TimeZone.getDefault();
+						}
+						tasks.add(this.registrar.scheduleCronTask(new CronTask(runnable, new CronTrigger(cron, timeZone))));
 					}
-					tasks.add(this.registrar.scheduleCronTask(new CronTask(runnable, new CronTrigger(cron, timeZone))));
 				}
 			}
 
@@ -478,12 +480,8 @@ public class ScheduledAnnotationBeanPostProcessor
 
 			// Finally register the scheduled tasks
 			synchronized (this.scheduledTasks) {
-				Set<ScheduledTask> registeredTasks = this.scheduledTasks.get(bean);
-				if (registeredTasks == null) {
-					registeredTasks = new LinkedHashSet<>(4);
-					this.scheduledTasks.put(bean, registeredTasks);
-				}
-				registeredTasks.addAll(tasks);
+				Set<ScheduledTask> regTasks = this.scheduledTasks.computeIfAbsent(bean, key -> new LinkedHashSet<>(4));
+				regTasks.addAll(tasks);
 			}
 		}
 		catch (IllegalArgumentException ex) {

spring-context/src/test/java/org/springframework/scheduling/annotation/ScheduledAnnotationBeanPostProcessorTests.java

@@ -45,6 +45,7 @@ import org.springframework.scheduling.Trigger;
 import org.springframework.scheduling.TriggerContext;
 import org.springframework.scheduling.config.CronTask;
 import org.springframework.scheduling.config.IntervalTask;
+import org.springframework.scheduling.config.ScheduledTaskHolder;
 import org.springframework.scheduling.config.ScheduledTaskRegistrar;
 import org.springframework.scheduling.support.CronTrigger;
 import org.springframework.scheduling.support.ScheduledMethodRunnable;
@@ -82,7 +83,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -108,7 +111,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -134,7 +139,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -195,7 +202,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(2, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -231,7 +240,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -259,7 +270,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -307,7 +320,7 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 	}
 
 	@Test(expected = BeanCreationException.class)
-	public void cronTaskWithMethodValidation() throws InterruptedException {
+	public void cronTaskWithMethodValidation() {
 		BeanDefinition validationDefinition = new RootBeanDefinition(MethodValidationPostProcessor.class);
 		BeanDefinition processorDefinition = new RootBeanDefinition(ScheduledAnnotationBeanPostProcessor.class);
 		BeanDefinition targetDefinition = new RootBeanDefinition(CronTestBean.class);
@@ -325,7 +338,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -350,7 +365,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar) new DirectFieldAccessor(
 			postProcessor).getPropertyValue("registrar");
@@ -376,7 +393,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -407,7 +426,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -424,6 +445,24 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		assertEquals(businessHoursCronExpression, task.getExpression());
 	}
 
+	@Test
+	public void propertyPlaceholderWithInactiveCron() {
+		String businessHoursCronExpression = "-";
+		BeanDefinition processorDefinition = new RootBeanDefinition(ScheduledAnnotationBeanPostProcessor.class);
+		BeanDefinition placeholderDefinition = new RootBeanDefinition(PropertyPlaceholderConfigurer.class);
+		Properties properties = new Properties();
+		properties.setProperty("schedules.businessHours", businessHoursCronExpression);
+		placeholderDefinition.getPropertyValues().addPropertyValue("properties", properties);
+		BeanDefinition targetDefinition = new RootBeanDefinition(PropertyPlaceholderWithCronTestBean.class);
+		context.registerBeanDefinition("postProcessor", processorDefinition);
+		context.registerBeanDefinition("placeholder", placeholderDefinition);
+		context.registerBeanDefinition("target", targetDefinition);
+		context.refresh();
+
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertTrue(postProcessor.getScheduledTasks().isEmpty());
+	}
+
 	@Test
 	public void propertyPlaceholderWithFixedDelayInMillis() {
 		propertyPlaceholderWithFixedDelay(false);
@@ -447,7 +486,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -488,7 +529,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -518,7 +561,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.getBeanFactory().registerSingleton("schedules", schedules);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -549,7 +594,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -574,7 +621,9 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		context.registerBeanDefinition("target", targetDefinition);
 		context.refresh();
 
-		Object postProcessor = context.getBean("postProcessor");
+		ScheduledTaskHolder postProcessor = context.getBean("postProcessor", ScheduledTaskHolder.class);
+		assertEquals(1, postProcessor.getScheduledTasks().size());
+
 		Object target = context.getBean("target");
 		ScheduledTaskRegistrar registrar = (ScheduledTaskRegistrar)
 				new DirectFieldAccessor(postProcessor).getPropertyValue("registrar");
@@ -803,6 +852,7 @@ public class ScheduledAnnotationBeanPostProcessorTests {
 		}
 	}
 
+
 	static class PropertyPlaceholderWithCronTestBean {
 
 		@Scheduled(cron = "${schedules.businessHours}")