Deserializer: BadRequestAlertException("Unknown property") with test code coverage

src/main/java/org/hostsharing/hsadminng/service/accessfilter/JsonDeserializerWithAccessFilter.java

@@ -163,7 +163,7 @@ public abstract class JsonDeserializerWithAccessFilter<T extends AccessMappings>
                     jsonFieldReader(node, field).readInto(dto);
                     updatingFields.add(field);
                 } catch (NoSuchFieldException e) {
-                    throw new RuntimeException("setting field " + fieldName + " failed", e);
+                    throw new BadRequestAlertException("Unknown property", fieldName, "unknownProperty");
                 }
             });
         }

src/main/java/org/hostsharing/hsadminng/service/util/ReflectionUtil.java

@@ -137,9 +137,24 @@ public class ReflectionUtil {
         T get() throws Exception;
     }
 
-    public static <T> T unchecked(final ThrowingSupplier<T> supplier) {
+    /**
+     * Catches checked exceptions and wraps these into an unchecked RuntimeException.
+     * <p>
+     * Rationale: Checked exceptions are a controversial Java feature to begin with.
+     * They often mix error handling code into the normal flow of domain rules
+     * or other technical aspects which is not only hard to read but also violates
+     * the Single Responsibility Principle. Often this is even worse for expressions
+     * than it is for statements.
+     * </p>
+     *
+     * @param expression an expresion which returns a T and may throw a checked exception
+     * @param <T> the result type of the expression
+     * @return the result of the expression
+     * @throws RuntimeException which wraps a checked exception thrown by the expression
+     */
+    public static <T> T unchecked(final ThrowingSupplier<T> expression) {
         try {
-            return supplier.get();
+            return expression.get();
         } catch (final Exception e) {
             throw new RuntimeException(e);
         }

src/main/webapp/i18n/de/custom-error.json

@@ -1,6 +1,7 @@
 {
     "error": {
         "idNotFound": "Technische Datensatz-ID nicht gefunden",
+        "unknownProperty": "Unbekannte Eigenschaft",
         "shareSubscriptionPositiveQuantity": "Zeichnungen von Geschäftsanteilen erfordern eine positive Stückzahl",
         "shareCancellationNegativeQuantity": "Kündigungen von Geschäftsanteilen erfordern eine negative Stückzahl",
         "shareTransactionImmutable": "Transaktionen mit Geschäftsanteilen sind unveränderlich",

src/main/webapp/i18n/en/custom-error.json

@@ -1,6 +1,7 @@
 {
     "error": {
         "idNotFound": "Technical record-ID not found",
+        "unknownProperty": "Unknown Property",
         "shareSubscriptionPositiveQuantity": "Share subscriptions require a positive quantity",
         "shareCancellationNegativeQuantity": "Share cancellations require a negative quantity",
         "shareTransactionImmutable": "Share transactions are immutable",

src/test/java/org/hostsharing/hsadminng/service/accessfilter/JSonDeserializationWithAccessFilterUnitTest.java

@@ -399,6 +399,24 @@ public class JSonDeserializationWithAccessFilterUnitTest {
                 .hasMessageContaining("GivenDtoWithUnknownFieldType.unknown");
     }
 
+    @Test
+    public void shouldDetectUnknownPropertyName() throws IOException {
+        // given
+        securityContext.havingAuthenticatedUser().withAuthority(AuthoritiesConstants.ADMIN);
+        givenJSonTree(asJSon(ImmutablePair.of("somePropWhichDoesNotExist", "Some Value")));
+
+        // when
+        final Throwable exception = catchThrowable(
+                () -> deserializerForGivenDto().deserialize(jsonParser, null));
+
+        // then
+        assertThat(exception).isInstanceOfSatisfying(BadRequestAlertException.class, (exc) -> {
+            assertThat(exc).hasMessageStartingWith("Unknown property");
+            assertThat(exc.getParam()).isEqualTo("somePropWhichDoesNotExist");
+            assumeThat(exc.getErrorKey()).isEqualTo("unknownProperty");
+        });
+    }
+
     // --- only fixture code below ---
 
     private void givenJSonTree(String givenJSon) throws IOException {