Refined CronSequenceGenerator's rounding up of seconds to address second-specific cron expressions

Issue: SPR-9459

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

@@ -71,7 +71,19 @@ public class CronSequenceGenerator {
 
 
 	/**
-	 * Construct a {@link CronSequenceGenerator} from the pattern provided.
+	 * Construct a {@link CronSequenceGenerator} from the pattern provided,
+	 * using the default {@link TimeZone}.
+	 * @param expression a space-separated list of time fields
+	 * @throws IllegalArgumentException if the pattern cannot be parsed
+	 * @see java.util.TimeZone#getDefault()
+	 */
+	public CronSequenceGenerator(String expression) {
+		this(expression, TimeZone.getDefault());
+	}
+
+	/**
+	 * Construct a {@link CronSequenceGenerator} from the pattern provided,
+	 * using the specified {@link TimeZone}.
 	 * @param expression a space-separated list of time fields
 	 * @param timeZone the TimeZone to use for generated trigger times
 	 * @throws IllegalArgumentException if the pattern cannot be parsed
@@ -114,12 +126,17 @@ public class CronSequenceGenerator {
 		calendar.setTimeZone(this.timeZone);
 		calendar.setTime(date);
 
-		// Truncate to the next whole second
-		calendar.add(Calendar.SECOND, 1);
+		// First, just reset the milliseconds and try to calculate from there...
 		calendar.set(Calendar.MILLISECOND, 0);
-
+		long originalTimestamp = calendar.getTimeInMillis();
 		doNext(calendar, calendar.get(Calendar.YEAR));
 
+		if (calendar.getTimeInMillis() == originalTimestamp) {
+			// We arrived at the original timestamp - round up to the next whole second and try again...
+			calendar.add(Calendar.SECOND, 1);
+			doNext(calendar, calendar.get(Calendar.YEAR));
+		}
+
 		return calendar.getTime();
 	}
 

spring-context/src/test/java/org/springframework/scheduling/support/CronSequenceGeneratorTests.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2002-2013 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
+ *
+ *      http://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.util.Date;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * @author Juergen Hoeller
+ */
+public class CronSequenceGeneratorTests {
+
+	@Test
+	public void testAt50Seconds() {
+		assertEquals(new Date(2012, 6, 2, 1, 0),
+				new CronSequenceGenerator("*/15 * 1-4 * * *").next(new Date(2012, 6, 1, 9, 53, 50)));
+	}
+
+	@Test
+	public void testAt0Seconds() {
+		assertEquals(new Date(2012, 6, 2, 1, 0),
+				new CronSequenceGenerator("*/15 * 1-4 * * *").next(new Date(2012, 6, 1, 9, 53)));
+	}
+
+	@Test
+	public void testAt0Minutes() {
+		assertEquals(new Date(2012, 6, 2, 1, 0),
+				new CronSequenceGenerator("0 */2 1-4 * * *").next(new Date(2012, 6, 1, 9, 0)));
+	}
+
+}

spring-context/src/test/java/org/springframework/scheduling/support/CronTriggerTests.java

@@ -41,7 +41,7 @@ import static org.junit.Assert.*;
 @RunWith(Parameterized.class)
 public class CronTriggerTests {
 
-	private Calendar calendar = new GregorianCalendar();
+	private final Calendar calendar = new GregorianCalendar();
 
 	private final Date date;
 
@@ -49,8 +49,8 @@ public class CronTriggerTests {
 
 
 	public CronTriggerTests(Date date, TimeZone timeZone) {
-		this.timeZone = timeZone;
 		this.date = date;
+		this.timeZone = timeZone;
 	}
 
 	@Parameters
@@ -66,6 +66,7 @@ public class CronTriggerTests {
 		calendar.set(Calendar.MILLISECOND, 0);
 	}
 
+
 	@Before
 	public void setUp() {
 		calendar.setTimeZone(timeZone);