Allow quartz expression in cron expression lists

This commit introduces support for lists of quartz cron fields, such
as "1L, LW" or "TUE#1, TUE#3, TUE#5".

Closes gh-26289

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

@@ -19,14 +19,13 @@ package org.springframework.scheduling.support;
 import java.time.DateTimeException;
 import java.time.temporal.Temporal;
 import java.time.temporal.ValueRange;
-import java.util.BitSet;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
- * Efficient {@link BitSet}-based extension of {@link CronField}.
+ * Efficient bitwise-operator extension of {@link CronField}.
  * Created using the {@code parse*} methods.
  *
  * @author Arjen Poutsma

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

@@ -0,0 +1,97 @@
+/*
+ * 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.
+ * 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.scheduling.support;
+
+import java.time.temporal.Temporal;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * Extension of {@link CronField} that wraps an array of cron fields.
+ *
+ * @author Arjen Poutsma
+ * @since 5.3.3
+ */
+final class CompositeCronField extends CronField {
+
+	private final CronField[] fields;
+
+	private final String value;
+
+
+	private CompositeCronField(Type type, CronField[] fields, String value) {
+		super(type);
+		this.fields = fields;
+		this.value = value;
+	}
+
+	/**
+	 * Composes the given fields into a {@link CronField}.
+	 */
+	public static CronField compose(CronField[] fields, Type type, String value) {
+		Assert.notEmpty(fields, "Fields must not be empty");
+		Assert.hasLength(value, "Value must not be empty");
+
+		if (fields.length == 1) {
+			return fields[0];
+		}
+		else {
+			return new CompositeCronField(type, fields, value);
+		}
+	}
+
+
+	@Nullable
+	@Override
+	public <T extends Temporal & Comparable<? super T>> T nextOrSame(T temporal) {
+		T result = null;
+		for (CronField field : this.fields) {
+			T candidate = field.nextOrSame(temporal);
+			if (result == null ||
+					candidate != null && candidate.compareTo(result) < 0) {
+				result = candidate;
+			}
+		}
+		return result;
+	}
+
+
+	@Override
+	public int hashCode() {
+		return this.value.hashCode();
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof CompositeCronField)) {
+			return false;
+		}
+		CompositeCronField other = (CompositeCronField) o;
+		return type() == other.type() &&
+				this.value.equals(other.value);
+	}
+
+	@Override
+	public String toString() {
+		return type() + " '" + this.value + "'";
+
+	}
+}

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

@@ -20,8 +20,10 @@ import java.time.DateTimeException;
 import java.time.temporal.ChronoField;
 import java.time.temporal.Temporal;
 import java.time.temporal.ValueRange;
+import java.util.function.BiFunction;
 
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 /**
@@ -77,11 +79,18 @@ abstract class CronField {
 	 * Parse the given value into a days of months {@code CronField}, the fourth entry of a cron expression.
 	 */
 	public static CronField parseDaysOfMonth(String value) {
-		if (value.contains("L") || value.contains("W")) {
-			return QuartzCronField.parseDaysOfMonth(value);
+		if (!QuartzCronField.isQuartzDaysOfMonthField(value)) {
+			return BitsCronField.parseDaysOfMonth(value);
 		}
 		else {
-			return BitsCronField.parseDaysOfMonth(value);
+			return parseList(value, Type.DAY_OF_MONTH, (field, type) -> {
+				if (QuartzCronField.isQuartzDaysOfMonthField(field)) {
+					return QuartzCronField.parseDaysOfMonth(field);
+				}
+				else {
+					return BitsCronField.parseDaysOfMonth(field);
+				}
+			});
 		}
 	}
 
@@ -98,15 +107,32 @@ abstract class CronField {
 	 */
 	public static CronField parseDaysOfWeek(String value) {
 		value = replaceOrdinals(value, DAYS);
-		if (value.contains("L") || value.contains("#")) {
-			return QuartzCronField.parseDaysOfWeek(value);
+		if (!QuartzCronField.isQuartzDaysOfWeekField(value)) {
+			return BitsCronField.parseDaysOfWeek(value);
 		}
 		else {
-			return BitsCronField.parseDaysOfWeek(value);
+			return parseList(value, Type.DAY_OF_WEEK, (field, type) -> {
+				if (QuartzCronField.isQuartzDaysOfWeekField(field)) {
+					return QuartzCronField.parseDaysOfWeek(field);
+				}
+				else {
+					return BitsCronField.parseDaysOfWeek(field);
+				}
+			});
 		}
 	}
 
 
+	private static CronField parseList(String value, Type type, BiFunction<String, Type, CronField> parseFieldFunction) {
+		Assert.hasLength(value, "Value must not be empty");
+		String[] fields = StringUtils.delimitedListToStringArray(value, ",");
+		CronField[] cronFields = new CronField[fields.length];
+		for (int i = 0; i < fields.length; i++) {
+			cronFields[i] = parseFieldFunction.apply(fields[i], type);
+		}
+		return CompositeCronField.compose(cronFields, type, value);
+	}
+
 	private static String replaceOrdinals(String value, String[] list) {
 		value = value.toUpperCase();
 		for (int i = 0; i < list.length; i++) {

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

@@ -78,6 +78,12 @@ final class QuartzCronField extends CronField {
 		this.rollForwardType = rollForwardType;
 	}
 
+	/**
+	 * Returns whether the given value is a Quartz day-of-month field.
+	 */
+	public static boolean isQuartzDaysOfMonthField(String value) {
+		return value.contains("L") || value.contains("W");
+	}
 
 	/**
 	 * Parse the given value into a days of months {@code QuartzCronField}, the fourth entry of a cron expression.
@@ -125,6 +131,13 @@ final class QuartzCronField extends CronField {
 		throw new IllegalArgumentException("No 'L' or 'W' found in '" + value + "'");
 	}
 
+	/**
+	 * Returns whether the given value is a Quartz day-of-week field.
+	 */
+	public static boolean isQuartzDaysOfWeekField(String value) {
+		return value.contains("L") || value.contains("#");
+	}
+
 	/**
 	 * Parse the given value into a days of week {@code QuartzCronField}, the sixth entry of a cron expression.
 	 * Expects a "L" or "#" in the given value.