#21: Add method Scheduler.remove(String jobName)

Author: amanteaux

src/main/java/com/coreoz/wisp/Scheduler.java

@@ -272,6 +272,27 @@ public CompletionStage<Job> cancel(String jobName) {
 		}
 	}
 
+	/**
+	 * Remove a terminated job, so with the status {@link JobStatus#DONE}),
+	 * from the monitored jobs. The monitored jobs are the ones
+	 * still referenced using {@link #jobStatus()}.
+	 *
+	 * This can be useful to avoid memory leak in case many jobs
+	 * with a short lifespan are created.
+	 * @param jobName The job name to remove
+	 * @throws IllegalArgumentException If there is no job corresponding to the job name or if the job is not on the status {@link JobStatus#DONE})
+	 */
+	public void remove(String jobName) {
+		Job jobToRemove = indexedJobsByName.get(jobName);
+		if (jobToRemove == null) {
+			throw new IllegalArgumentException("There is no existing job with the name " + jobName);
+		}
+		if(jobToRemove.status() != JobStatus.DONE) {
+			throw new IllegalArgumentException("Job is not terminated. Need to call the cancel() method before trying to remove it?");
+		}
+		indexedJobsByName.remove(jobName);
+	}
+
 	/**
 	 * Wait until the current running jobs are executed
 	 * and cancel jobs that are planned to be executed.

src/test/java/com/coreoz/wisp/SchedulerTest.java

@@ -7,6 +7,7 @@
 import java.time.Duration;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import com.coreoz.wisp.schedule.Schedule;
 import org.assertj.core.data.Offset;
 import org.junit.Test;
 import org.slf4j.Logger;
@@ -311,4 +312,25 @@ public void check_that_metrics_are_correctly_updated_during_and_after_a_job_exec
 		assertThat(job.threadRunningJob()).isNull();
 	}
 
+	@Test
+	public void remove__verify_that_a_done_job_is_correctly_removed() {
+		Scheduler scheduler = new Scheduler();
+		Job job = scheduler.schedule(Utils.doNothing(), Schedule.willNeverBeExecuted);
+		assertThat(scheduler.jobStatus()).contains(job);
+		scheduler.remove(job.name());
+		assertThat(scheduler.jobStatus()).isEmpty();
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void remove__verify_that_a_non_existent_job_name_raises_an_illegal_argument_exception() {
+		Scheduler scheduler = new Scheduler();
+		scheduler.remove("does not exist");
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void remove__verify_that_a_non_done_job_name_raises_an_illegal_argument_exception() {
+		Scheduler scheduler = new Scheduler();
+		Job job = scheduler.schedule(Utils.doNothing(), Schedules.fixedDelaySchedule(Duration.ofMillis(1000)));
+		scheduler.remove(job.name());
+	}
 }