Fixed the compare filter to handle subclasses (#17169)

Earlier the comparision worked only if the item value was a subclass of
the value in comparator, but not in the other way around. Now the
compairision works if the one is a subclass of the other and both
implements Comparable.

Change-Id: I1bcbba94f1263915f838e948ed9d8b68a14aefd0

1 files changed, 9 insertions, 3 deletions

diff --git a/server/src/main/java/com/vaadin/data/util/filter/Compare.java b/server/src/main/java/com/vaadin/data/util/filter/Compare.java
index 1fcbe85580..60523f2d42 100644
--- a/server/src/main/java/com/vaadin/data/util/filter/Compare.java
+++ b/server/src/main/java/com/vaadin/data/util/filter/Compare.java
@@ -292,9 +292,15 @@ public abstract class Compare implements Filter {
             return null == value1 ? 0 : -1;
         } else if (null == value1) {
             return 1;
-        } else if (getValue() instanceof Comparable
-                && value1.getClass().isAssignableFrom(getValue().getClass())) {
-            return -((Comparable) getValue()).compareTo(value1);
+        } else if (getValue() instanceof Comparable) {
+            if (value1.getClass().isInstance(getValue())) {
+                return -((Comparable) getValue()).compareTo(value1);
+            } else if (getValue().getClass().isInstance(value1)) {
+                // isInstance returns true if value1 is a sub-type of
+                // getValue(), i.e. value1 must here be Comparable
+                return ((Comparable) value1).compareTo(getValue());
+            }
+
         }
         throw new IllegalArgumentException("Could not compare the arguments: "
                 + value1 + ", " + getValue());