Add withJitter(maxJitterMs) to QueryRunner.DelayStrategy

common/src/main/java/com/moparisthebest/jdbc/QueryRunner.java

@@ -164,6 +164,12 @@ public class QueryRunner<T extends JdbcMapper> {
 
 	public static interface DelayStrategy {
 		long getDelay(int attempt);
+
+		//IFJAVA8_START
+		default DelayStrategy withJitter(final int maxJitterMs) {
+			return QueryRunner.withJitter(this, maxJitterMs);
+		}
+		//IFJAVA8_END
 	}
 
 	public static DelayStrategy exponentialBackoff() {
@@ -231,6 +237,24 @@ public class QueryRunner<T extends JdbcMapper> {
 		IFJAVA6_END*/
 	}
 
+	public static DelayStrategy withJitter(final DelayStrategy toWrap, final int maxJitterMs) {
+		return
+		/*IFJAVA6_START
+			new DelayStrategy() {
+			@Override
+			public long getDelay(final int attempt) {
+				return
+		IFJAVA6_END*/
+		//IFJAVA8_START
+				(attempt) ->
+		//IFJAVA8_END
+						toWrap.getDelay(attempt) + ThreadLocalRandom.current().nextInt(maxJitterMs);
+		/*IFJAVA6_START
+			}
+		};
+		IFJAVA6_END*/
+	}
+
 	/*IFJAVA6_START
 	// terrible, I know, use java8
 	private static class ThreadLocalRandom {

querymapper/src/test/java/com/moparisthebest/jdbc/QueryRunnerTest.java

@@ -19,7 +19,7 @@ public class QueryRunnerTest {
 		public Connection create() throws SQLException {
 			return QueryMapperTest.getConnection();
 		}
-	}), QueryRunner.fixedDelay(5));
+	}), QueryRunner.withJitter(QueryRunner.fixedDelay(5), 5));
 
 	private void testPerson(final Person expected, final String query) throws Throwable {
 		final Person actual =