Use nanosecond precision for scheduling (aligned with calculations)

Closes gh-30666

spring-context/src/main/java/org/springframework/scheduling/TriggerContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -27,6 +27,7 @@
  * of a given task.
  *
  * @author Juergen Hoeller
+ * @author Arjen Poutsma
  * @since 3.0
  */
 public interface TriggerContext {
@@ -78,6 +79,7 @@ default Date lastActualExecutionTime() {
 	/**
 	 * Return the last <i>actual</i> execution time of the task,
 	 * or {@code null} if not scheduled before.
+	 * @since 6.0
 	 */
 	@Nullable
 	Instant lastActualExecution();
@@ -98,6 +100,7 @@ default Date lastCompletionTime() {
 	/**
 	 * Return the last completion time of the task,
 	 * or {@code null} if not scheduled before.
+	 * @since 6.0
 	 */
 	@Nullable
 	Instant lastCompletion();

spring-context/src/main/java/org/springframework/scheduling/concurrent/ConcurrentTaskScheduler.java

@@ -211,7 +211,7 @@ public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
 	public ScheduledFuture<?> schedule(Runnable task, Instant startTime) {
 		Duration initialDelay = Duration.between(this.clock.instant(), startTime);
 		try {
-			return this.scheduledExecutor.schedule(decorateTask(task, false), initialDelay.toMillis(), TimeUnit.MILLISECONDS);
+			return this.scheduledExecutor.schedule(decorateTask(task, false), initialDelay.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + this.scheduledExecutor + "] did not accept task: " + task, ex);
@@ -222,7 +222,7 @@ public ScheduledFuture<?> schedule(Runnable task, Instant startTime) {
 	public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Instant startTime, Duration period) {
 		Duration initialDelay = Duration.between(this.clock.instant(), startTime);
 		try {
-			return this.scheduledExecutor.scheduleAtFixedRate(decorateTask(task, true), initialDelay.toMillis(), period.toMillis(), TimeUnit.MILLISECONDS);
+			return this.scheduledExecutor.scheduleAtFixedRate(decorateTask(task, true), initialDelay.toNanos(), period.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + this.scheduledExecutor + "] did not accept task: " + task, ex);
@@ -232,7 +232,7 @@ public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Instant startTime,
 	@Override
 	public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Duration period) {
 		try {
-			return this.scheduledExecutor.scheduleAtFixedRate(decorateTask(task, true), 0, period.toMillis(), TimeUnit.MILLISECONDS);
+			return this.scheduledExecutor.scheduleAtFixedRate(decorateTask(task, true), 0, period.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + this.scheduledExecutor + "] did not accept task: " + task, ex);
@@ -243,7 +243,7 @@ public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Duration period) {
 	public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Instant startTime, Duration delay) {
 		Duration initialDelay = Duration.between(this.clock.instant(), startTime);
 		try {
-			return this.scheduledExecutor.scheduleWithFixedDelay(decorateTask(task, true), initialDelay.toMillis(), delay.toMillis(), TimeUnit.MILLISECONDS);
+			return this.scheduledExecutor.scheduleWithFixedDelay(decorateTask(task, true), initialDelay.toNanos(), delay.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + this.scheduledExecutor + "] did not accept task: " + task, ex);
@@ -253,7 +253,7 @@ public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Instant startTim
 	@Override
 	public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Duration delay) {
 		try {
-			return this.scheduledExecutor.scheduleWithFixedDelay(decorateTask(task, true), 0, delay.toMillis(), TimeUnit.MILLISECONDS);
+			return this.scheduledExecutor.scheduleWithFixedDelay(decorateTask(task, true), 0, delay.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + this.scheduledExecutor + "] did not accept task: " + task, ex);

spring-context/src/main/java/org/springframework/scheduling/concurrent/ReschedulingRunnable.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 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.
@@ -80,7 +80,7 @@ public ScheduledFuture<?> schedule() {
 				return null;
 			}
 			Duration initialDelay = Duration.between(this.triggerContext.getClock().instant(), this.scheduledExecutionTime);
-			this.currentFuture = this.executor.schedule(this, initialDelay.toMillis(), TimeUnit.MILLISECONDS);
+			this.currentFuture = this.executor.schedule(this, initialDelay.toNanos(), TimeUnit.NANOSECONDS);
 			return this;
 		}
 	}
@@ -158,8 +158,8 @@ public int compareTo(Delayed other) {
 		if (this == other) {
 			return 0;
 		}
-		long diff = getDelay(TimeUnit.MILLISECONDS) - other.getDelay(TimeUnit.MILLISECONDS);
-		return (diff == 0 ? 0 : ((diff < 0)? -1 : 1));
+		long diff = getDelay(TimeUnit.NANOSECONDS) - other.getDelay(TimeUnit.NANOSECONDS);
+		return (diff == 0 ? 0 : (diff < 0 ? -1 : 1));
 	}
 
 }

spring-context/src/main/java/org/springframework/scheduling/concurrent/ThreadPoolTaskScheduler.java

@@ -382,7 +382,7 @@ public ScheduledFuture<?> schedule(Runnable task, Instant startTime) {
 		ScheduledExecutorService executor = getScheduledExecutor();
 		Duration initialDelay = Duration.between(this.clock.instant(), startTime);
 		try {
-			return executor.schedule(errorHandlingTask(task, false), initialDelay.toMillis(), TimeUnit.MILLISECONDS);
+			return executor.schedule(errorHandlingTask(task, false), initialDelay.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
@@ -394,7 +394,7 @@ public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Instant startTime,
 		ScheduledExecutorService executor = getScheduledExecutor();
 		Duration initialDelay = Duration.between(this.clock.instant(), startTime);
 		try {
-			return executor.scheduleAtFixedRate(errorHandlingTask(task, true), initialDelay.toMillis(), period.toMillis(), TimeUnit.MILLISECONDS);
+			return executor.scheduleAtFixedRate(errorHandlingTask(task, true), initialDelay.toNanos(), period.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
@@ -405,7 +405,7 @@ public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Instant startTime,
 	public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Duration period) {
 		ScheduledExecutorService executor = getScheduledExecutor();
 		try {
-			return executor.scheduleAtFixedRate(errorHandlingTask(task, true), 0, period.toMillis(), TimeUnit.MILLISECONDS);
+			return executor.scheduleAtFixedRate(errorHandlingTask(task, true), 0, period.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
@@ -417,7 +417,7 @@ public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Instant startTim
 		ScheduledExecutorService executor = getScheduledExecutor();
 		Duration initialDelay = Duration.between(this.clock.instant(), startTime);
 		try {
-			return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), initialDelay.toMillis(), delay.toMillis(), TimeUnit.MILLISECONDS);
+			return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), initialDelay.toNanos(), delay.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
@@ -428,7 +428,7 @@ public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Instant startTim
 	public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Duration delay) {
 		ScheduledExecutorService executor = getScheduledExecutor();
 		try {
-			return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), 0, delay.toMillis(), TimeUnit.MILLISECONDS);
+			return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), 0, delay.toNanos(), TimeUnit.NANOSECONDS);
 		}
 		catch (RejectedExecutionException ex) {
 			throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);

spring-context/src/main/java/org/springframework/scheduling/config/ScheduledTaskRegistrar.java

@@ -485,7 +485,7 @@ public ScheduledTask scheduleFixedRateTask(FixedRateTask task) {
 		}
 		if (this.taskScheduler != null) {
 			Duration initialDelay = task.getInitialDelayDuration();
-			if (initialDelay.toMillis() > 0) {
+			if (initialDelay.toNanos() > 0) {
 				Instant startTime = this.taskScheduler.getClock().instant().plus(initialDelay);
 				scheduledTask.future =
 						this.taskScheduler.scheduleAtFixedRate(task.getRunnable(), startTime, task.getIntervalDuration());

spring-context/src/main/java/org/springframework/scheduling/support/CronExpression.java

@@ -57,18 +57,12 @@ public final class CronExpression {
 	private final String expression;
 
 
-	private CronExpression(
-			CronField seconds,
-			CronField minutes,
-			CronField hours,
-			CronField daysOfMonth,
-			CronField months,
-			CronField daysOfWeek,
-			String expression) {
+	private CronExpression(CronField seconds, CronField minutes, CronField hours,
+			CronField daysOfMonth, CronField months, CronField daysOfWeek, String expression) {
 
-		// reverse order, to make big changes first
-		// to make sure we end up at 0 nanos, we add an extra field
-		this.fields = new CronField[]{daysOfWeek, months, daysOfMonth, hours, minutes, seconds, CronField.zeroNanos()};
+		// Reverse order, to make big changes first.
+		// To make sure we end up at 0 nanos, we add an extra field.
+		this.fields = new CronField[] {daysOfWeek, months, daysOfMonth, hours, minutes, seconds, CronField.zeroNanos()};
 		this.expression = expression;
 	}
 
@@ -268,26 +262,18 @@ private <T extends Temporal & Comparable<? super T>> T nextOrSameInternal(T temp
 
 
 	@Override
-	public int hashCode() {
-		return Arrays.hashCode(this.fields);
+	public boolean equals(@Nullable Object other) {
+		return (this == other || (other instanceof CronExpression that &&
+				Arrays.equals(this.fields, that.fields)));
 	}
 
 	@Override
-	public boolean equals(@Nullable Object o) {
-		if (this == o) {
-			return true;
-		}
-		if (o instanceof CronExpression other) {
-			return Arrays.equals(this.fields, other.fields);
-		}
-		else {
-			return false;
-		}
+	public int hashCode() {
+		return Arrays.hashCode(this.fields);
 	}
 
 	/**
 	 * Return the expression string used to create this {@code CronExpression}.
-	 * @return the expression string
 	 */
 	@Override
 	public String toString() {

spring-context/src/main/java/org/springframework/scheduling/support/CronTrigger.java

@@ -89,7 +89,7 @@ public String getExpression() {
 	/**
 	 * Determine the next execution time according to the given trigger context.
 	 * <p>Next execution times are calculated based on the
-	 * {@linkplain TriggerContext#lastCompletionTime completion time} of the
+	 * {@linkplain TriggerContext#lastCompletion completion time} of the
 	 * previous execution; therefore, overlapping executions won't occur.
 	 */
 	@Override
@@ -114,8 +114,9 @@ public Instant nextExecution(TriggerContext triggerContext) {
 
 
 	@Override
-	public boolean equals(@Nullable Object obj) {
-		return (this == obj || (obj instanceof CronTrigger that && this.expression.equals(that.expression)));
+	public boolean equals(@Nullable Object other) {
+		return (this == other || (other instanceof CronTrigger that &&
+				this.expression.equals(that.expression)));
 	}
 
 	@Override