Add convenience factory methods to JobSchedule (#134)

* Add convenience factory methods to JobSchedule

* Add ofIntervalDelay factory methods to JobSchedule; one accepts a
  io.dropwizard.Duration and the other accepts a java.time.Duration

Closes #133

src/main/java/org/kiwiproject/dropwizard/util/config/JobSchedule.java

@@ -1,5 +1,7 @@
 package org.kiwiproject.dropwizard.util.config;
 
+import static org.kiwiproject.base.KiwiPreconditions.checkArgumentNotNull;
+
 import io.dropwizard.util.Duration;
 import lombok.AccessLevel;
 import lombok.AllArgsConstructor;
@@ -20,13 +22,15 @@
 @AllArgsConstructor(access = AccessLevel.PACKAGE)
 public class JobSchedule {
 
+    static final Duration DEFAULT_INITIAL_DELAY = Duration.seconds(30);
+
     /**
      * Initial delay before the job will run. This should be passed to the ScheduledExecutor's initialDelay. Defaults
      * to 30 seconds.
      */
     @NotNull
     @Builder.Default
-    private Duration initialDelay = Duration.seconds(30);
+    private Duration initialDelay = DEFAULT_INITIAL_DELAY;
 
     /**
      * Delay between job runs.  If using a fixedDelay, this will be the time between the end of one job run and the
@@ -36,4 +40,39 @@ public class JobSchedule {
     @NotNull
     private Duration intervalDelay;
 
+    /**
+     * Create a new {@link JobSchedule} instance with the given interval delay and the default initial delay.
+     * <p>
+     * This is useful when programmatically creating JobSchedule objects.
+     *
+     * @param intervalDelay the interval delay as a Dropwizard {@link Duration}
+     * @return a new instance
+     */
+    public static JobSchedule ofIntervalDelay(Duration intervalDelay) {
+        checkIntervalDelayNotNull(intervalDelay);
+
+        return JobSchedule.builder()
+                .intervalDelay(intervalDelay)
+                .build();
+    }
+
+    /**
+     * Create a new {@link JobSchedule} instance with the given interval delay and the default initial delay.
+     * <p>
+     * This is useful when programmatically creating JobSchedule objects.
+     *
+     * @param intervalDelay the interval delay as a JDK {@link java.time.Duration}
+     * @return a new instance
+     */
+    public static JobSchedule ofIntervalDelay(java.time.Duration intervalDelay) {
+        checkIntervalDelayNotNull(intervalDelay);
+
+        return JobSchedule.builder()
+                .intervalDelay(Duration.milliseconds(intervalDelay.toMillis()))
+                .build();
+    }
+
+    private static void checkIntervalDelayNotNull(Object intervalDelay) {
+        checkArgumentNotNull(intervalDelay, "intervalDelay must not be null");
+    }
 }

src/test/java/org/kiwiproject/dropwizard/util/config/JobScheduleTest.java

@@ -0,0 +1,49 @@
+package org.kiwiproject.dropwizard.util.config;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+
+import io.dropwizard.util.Duration;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+@DisplayName("JobSchedule")
+class JobScheduleTest {
+
+    @Nested
+    class OfIntervalDelay {
+
+        public static final int SECONDS = 45;
+
+        @Test
+        void shouldNotPermitNullDropwizardDuration() {
+            assertThatIllegalArgumentException().isThrownBy(() ->
+                    JobSchedule.ofIntervalDelay((Duration) null))
+                    .withMessage("intervalDelay must not be null");
+        }
+
+        @Test
+        void shouldCreateInstanceWithDropwizardDuration() {
+            var jobSchedule = JobSchedule.ofIntervalDelay(Duration.seconds(SECONDS));
+
+            assertThat(jobSchedule.getInitialDelay()).isEqualTo(JobSchedule.DEFAULT_INITIAL_DELAY);
+            assertThat(jobSchedule.getIntervalDelay().toSeconds()).isEqualTo(SECONDS);
+        }
+
+        @Test
+        void shouldNotPermitNullJavaTimeDuration() {
+            assertThatIllegalArgumentException().isThrownBy(() ->
+                    JobSchedule.ofIntervalDelay((java.time.Duration) null))
+                    .withMessage("intervalDelay must not be null");
+        }
+
+        @Test
+        void shouldCreateInstanceWithJavaTimeDuration() {
+            var jobSchedule = JobSchedule.ofIntervalDelay(java.time.Duration.ofSeconds(SECONDS));
+
+            assertThat(jobSchedule.getInitialDelay()).isEqualTo(JobSchedule.DEFAULT_INITIAL_DELAY);
+            assertThat(jobSchedule.getIntervalDelay().toSeconds()).isEqualTo(SECONDS);
+        }
+    }
+}