BAEL-9173: Getting Next Fire Time of Quartz (#18321)

* BAEL-9173: Getting Next Fire Time of Quartz

* BAEL-9173: Getting Next Fire Time of Quartz

* BAEL-9173: Getting Next Fire Time of Quartz (fix precision issue)

* BAEL-9173: Getting Next Fire Time of Quartz (fix precision issue)

Author: achraftt

libraries/src/main/java/com/baeldung/quartz/SimpleJob.java

@@ -1,9 +1,8 @@
 package com.baeldung.quartz;
 
-import org.quartz.Job;
-import org.quartz.JobDataMap;
-import org.quartz.JobExecutionContext;
-import org.quartz.JobExecutionException;
+import org.quartz.*;
+
+import java.util.Date;
 
 public class SimpleJob implements Job {
 
@@ -14,5 +13,10 @@ public void execute(JobExecutionContext context) throws JobExecutionException {
         float myFloatValue = dataMap.getFloat("myFloatValue");
 
         System.out.println("Job says: " + jobSays + ", and val is: " + myFloatValue);
+
+        // Access the Trigger to get the next fire time
+        Trigger trigger = context.getTrigger();
+        Date nextFireTime = trigger.getNextFireTime();
+        System.out.println("Next execution: " + nextFireTime);
     }
 }

libraries/src/test/java/com/baeldung/quartz/QuartzUnitTest.java

@@ -0,0 +1,42 @@
+package com.baeldung.quartz;
+
+import org.junit.jupiter.api.Test;
+import org.quartz.CronExpression;
+
+import java.text.ParseException;
+import java.util.Calendar;
+import java.util.Date;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+public class QuartzUnitTest {
+
+@Test
+void givenCronExpressionAndTestTime_whenCalculatingNextFireTime_thenCorrectNextFireTimeIsReturned() throws ParseException {
+    String cronExpression = "0 0/2 8-17 * * ?"; // Fires every 2 minutes between 8 AM and 5 PM
+    CronExpression expression = new CronExpression(cronExpression);
+
+    Calendar calendar = Calendar.getInstance();
+    calendar.set(Calendar.HOUR_OF_DAY, 10);
+    calendar.set(Calendar.MINUTE, 0);
+    calendar.set(Calendar.SECOND, 0);
+    calendar.set(Calendar.MILLISECOND, 0);  // Ensure no milliseconds for testTime
+    Date testTime = calendar.getTime(); // Set a fixed time: 10:00 AM
+
+    Date nextFireTime = expression.getNextValidTimeAfter(testTime);
+
+    assertNotNull(nextFireTime);
+
+    // The next fire time should be at 10:02 AM
+    calendar.add(Calendar.MINUTE, 2);
+    Date expectedNextFireTime = calendar.getTime();
+
+    // Compare the times in seconds (ignoring milliseconds)
+    long nextFireTimeInSeconds = nextFireTime.getTime() / 1000;
+    long expectedNextFireTimeInSeconds = expectedNextFireTime.getTime() / 1000;
+
+    assertEquals(expectedNextFireTimeInSeconds, nextFireTimeInSeconds);
+}
+
+}