[client] Refactor change monitor classes, better error message handling

1 files changed, 8 insertions, 3 deletions

diff --git a/dozentenmodul/src/main/java/org/openslx/dozmod/gui/helper/DateTimeHelper.java b/dozentenmodul/src/main/java/org/openslx/dozmod/gui/helper/DateTimeHelper.java
index 0b02bbf9..bd54a33c 100644
--- a/dozentenmodul/src/main/java/org/openslx/dozmod/gui/helper/DateTimeHelper.java
+++ b/dozentenmodul/src/main/java/org/openslx/dozmod/gui/helper/DateTimeHelper.java
@@ -14,19 +14,24 @@ public class DateTimeHelper {
 
 	/**
 	 * Returns the Date composed of the given datePicker's date and the given
-	 * timeSpinner's time
+	 * timeSpinner's time. Returns null if the model of either one doesn't
+	 * return a Date instance.
 	 * 
 	 * @param datePicker to extract the date from
 	 * @param timeSpinner to extract the time from
-	 * @return Date represented by datePicker's day and timeSpinner's time
+	 * @return Date represented by datePicker's day and timeSpinner's time,
+	 *         {@code null} on error
 	 */
 	public static Date getDateFrom(JDatePicker datePicker, JSpinner timeSpinner) {
 		// start date from the DatePicker
 		int years = datePicker.getModel().getYear();
 		int months = datePicker.getModel().getMonth();
 		int days = datePicker.getModel().getDay();
+		Object oTime = timeSpinner.getValue();
+		if (!(oTime instanceof Date) || years < 1000)
+			return null;
 		// start time from the Spinner
-		Date time = (Date) timeSpinner.getValue();
+		Date time = (Date)oTime;
 		Calendar calendar = Calendar.getInstance();
 		calendar.setTime(time);
 		int hours = calendar.get(Calendar.HOUR_OF_DAY);