removed bloat-code from JsonComponents in DTOs

build.gradle

@@ -156,7 +156,8 @@ def jhipsterGeneratedClassesWithLowCoverage = [
 
 def specialExceptions = [
     // lots of unreachable code due to error handling / verifications
-    'org.hostsharing.hsadminng.service.accessfilter.JSonAccessFilter'
+    'org.hostsharing.hsadminng.service.accessfilter.JSonAccessFilter',
+    'org.hostsharing.hsadminng.service.util.ReflectionUtil'
 ]
 
 jacocoTestCoverageVerification {

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

@@ -0,0 +1,9 @@
+package org.hostsharing.hsadminng.service.accessfilter;
+
+import java.io.Serializable;
+
+/**
+ * A marker interface for DTO classes which can be used by {@link JsonSerializerWithAccessFilter} and {@link JsonDeserializerWithAccessFilter}.
+ */
+public interface AccessMappings extends Serializable {
+}

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

@@ -10,8 +10,6 @@ import org.springframework.context.ApplicationContext;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Field;
-import java.lang.reflect.ParameterizedType;
-import java.lang.reflect.Type;
 
 import static com.google.common.base.Verify.verify;
 
@@ -67,28 +65,16 @@ abstract class JSonAccessFilter<T> {
 
         final ParentId parentIdAnnot = parentIdField.getAnnotation(ParentId.class);
         final Class<? extends IdToDtoResolver> parentDtoLoader = parentIdAnnot.resolver();
-        final Class<?> parentDtoClass = getGenericClassParameter(parentDtoLoader);
+        final Class<IdToDtoResolver> rawType = IdToDtoResolver.class;
-        final Long parentId = (Long) ReflectionUtil.getValue(dto, parentIdField);
+
+        final Class<?> parentDtoClass = ReflectionUtil.<T>determineGenericInterfaceParameter(parentDtoLoader, rawType, 0);
+        final Long parentId = ReflectionUtil.getValue(dto, parentIdField);
         final Role roleOnParent = SecurityUtils.getLoginUserRoleFor(parentDtoClass, parentId);
 
         final Object parentEntity = loadDto(parentDtoLoader, parentId);
         return Role.broadest(baseRole, getLoginUserRoleOnAncestorOfDtoClassIfHigher(roleOnParent, parentEntity));
     }
 
-    @SuppressWarnings("unchecked")
-    private Class<T> getGenericClassParameter(Class<? extends IdToDtoResolver> parentDtoLoader) {
-        for (Type genericInterface : parentDtoLoader.getGenericInterfaces()) {
-            if (genericInterface instanceof ParameterizedType) {
-                final ParameterizedType parameterizedType = (ParameterizedType) genericInterface;
-                if (parameterizedType.getRawType()== IdToDtoResolver.class) {
-                    return (Class<T>) parameterizedType.getActualTypeArguments()[0];
-                }
-            }
-
-        }
-        throw new AssertionError(parentDtoLoader.getSimpleName() + " expected to implement " + IdToDtoResolver.class.getSimpleName() + "<...DTO>");
-    }
-
     @SuppressWarnings("unchecked")
     protected Object loadDto(final Class<? extends IdToDtoResolver> resolverClass, final Long id) {
         verify(id != null,  "id must not be null for " + resolverClass.getSimpleName());

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

@@ -18,12 +18,18 @@ import java.util.Set;
 
 import static org.hostsharing.hsadminng.service.util.ReflectionUtil.unchecked;
 
-public class JSonDeserializerWithAccessFilter<T> extends JSonAccessFilter<T> {
+/** Actual implementation of JSON deserialization, where {link JSonDeserializerWithAccessFilter}
+ * is a stateless bean, {@link JSonDeserializationWithAccessFilter} exists only during the actual
+ * deserialization and contains a deserialization state.
+ *
+ * @param <T> DTO class to serialize
+ */
+public class JSonDeserializationWithAccessFilter<T> extends JSonAccessFilter<T> {
 
     private final TreeNode treeNode;
     private final Set<Field> writtenFields = new HashSet<>();
 
-    public JSonDeserializerWithAccessFilter(final ApplicationContext ctx, final JsonParser jsonParser, final DeserializationContext deserializationContext, Class<T> dtoClass) {
+    public JSonDeserializationWithAccessFilter(final ApplicationContext ctx, final JsonParser jsonParser, final DeserializationContext deserializationContext, Class<T> dtoClass) {
         super(ctx, unchecked(dtoClass::newInstance));
         this.treeNode = unchecked(() -> jsonParser.getCodec().readTree(jsonParser));
     }
@@ -113,7 +119,7 @@ public class JSonDeserializerWithAccessFilter<T> extends JSonAccessFilter<T> {
         } else if (Boolean.class.isAssignableFrom(field.getType()) || boolean.class.isAssignableFrom(field.getType())) {
             ReflectionUtil.setValue(dto, field, Boolean.valueOf(value.toString()));
         } else if (field.getType().isEnum()) {
-            ReflectionUtil.setValue(dto, field, Enum.valueOf((Class<Enum>) field.getType(), value.toString()));
+            ReflectionUtil.setValue(dto, field, ReflectionUtil.asEnumValue(field.getType(), value));
         } else if (LocalDate.class.isAssignableFrom(field.getType())) {
             ReflectionUtil.setValue(dto, field, LocalDate.parse(value.toString()));
         } else {

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

@@ -12,14 +12,20 @@ import java.lang.reflect.Field;
 import java.math.BigDecimal;
 import java.time.LocalDate;
 
-public class JSonSerializerWithAccessFilter<T> extends JSonAccessFilter<T> {
+/** Actual implementation of JSON serialization, where {link JsonSerializerWithAccessFilter}
+ * is a stateless bean, {@link JSonSerializationWithAccessFilter} exists only during the actual
+ * serialization and contains a serialization state.
+ *
+ * @param <T> DTO class to serialize
+ */
+public class JSonSerializationWithAccessFilter<T> extends JSonAccessFilter<T> {
     private final JsonGenerator jsonGenerator;
     private final SerializerProvider serializerProvider;
 
-    public JSonSerializerWithAccessFilter(final ApplicationContext ctx,
+    public JSonSerializationWithAccessFilter(final ApplicationContext ctx,
-                                          final JsonGenerator jsonGenerator,
+                                             final JsonGenerator jsonGenerator,
-                                          final SerializerProvider serializerProvider,
+                                             final SerializerProvider serializerProvider,
-                                          final T dto) {
+                                             final T dto) {
         super(ctx, dto);
         this.jsonGenerator = jsonGenerator;
         this.serializerProvider = serializerProvider;

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

@@ -0,0 +1,24 @@
+package org.hostsharing.hsadminng.service.accessfilter;
+
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JsonDeserializer;
+import org.hostsharing.hsadminng.service.util.ReflectionUtil;
+import org.springframework.context.ApplicationContext;
+
+public abstract class JsonDeserializerWithAccessFilter<T extends AccessMappings> extends JsonDeserializer<T> {
+
+    private final ApplicationContext ctx;
+
+    public JsonDeserializerWithAccessFilter(final ApplicationContext ctx) {
+        this.ctx = ctx;
+    }
+
+    @Override
+    public T deserialize(final JsonParser jsonParser,
+                         final DeserializationContext deserializationContext) {
+
+        final Class<T> dtoClass = ReflectionUtil.determineGenericClassParameter(this.getClass(), JsonDeserializerWithAccessFilter.class, 0);
+        return new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, deserializationContext, dtoClass).deserialize();
+    }
+}

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

@@ -0,0 +1,31 @@
+package org.hostsharing.hsadminng.service.accessfilter;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import org.springframework.context.ApplicationContext;
+
+import java.io.IOException;
+
+/** A base class for a Spring bean for JSON serialization with field-based access filters.
+ * Where {@link JSonSerializationWithAccessFilter} is the actual stateful implementation and
+ * it's instances only exist during the process of serialization, this class is a stateless just
+ * used for service and context injection.
+ *
+ * @param <T> DTO class to serialize
+ */
+public abstract class JsonSerializerWithAccessFilter<T extends AccessMappings> extends JsonSerializer<T> {
+
+    protected final ApplicationContext ctx;
+
+    public JsonSerializerWithAccessFilter(final ApplicationContext ctx) {
+        this.ctx = ctx;
+    }
+
+    @Override
+    public void serialize(final T dto, final JsonGenerator jsonGenerator,
+                          final SerializerProvider serializerProvider) throws IOException {
+
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, serializerProvider, dto).serialize();
+    }
+}

src/main/java/org/hostsharing/hsadminng/service/dto/CustomerDTO.java

@@ -1,11 +1,5 @@
 package org.hostsharing.hsadminng.service.dto;
 
-import com.fasterxml.jackson.core.JsonGenerator;
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.databind.DeserializationContext;
-import com.fasterxml.jackson.databind.JsonDeserializer;
-import com.fasterxml.jackson.databind.JsonSerializer;
-import com.fasterxml.jackson.databind.SerializerProvider;
 import org.hostsharing.hsadminng.domain.enumeration.CustomerKind;
 import org.hostsharing.hsadminng.domain.enumeration.VatRegion;
 import org.hostsharing.hsadminng.service.CustomerService;
@@ -14,15 +8,13 @@ import org.springframework.boot.jackson.JsonComponent;
 import org.springframework.context.ApplicationContext;
 
 import javax.validation.constraints.*;
-import java.io.IOException;
-import java.io.Serializable;
 import java.time.LocalDate;
 import java.util.Objects;
 
 /**
  * A DTO for the Customer entity.
  */
-public class CustomerDTO extends FluentBuilder<CustomerDTO> implements Serializable {
+public class CustomerDTO extends FluentBuilder<CustomerDTO> implements AccessMappings {
 
     @SelfId(resolver = CustomerService.class)
     @AccessFor(read = Role.ANY_CUSTOMER_USER)
@@ -265,36 +257,18 @@ public class CustomerDTO extends FluentBuilder<CustomerDTO> implements Serializa
     }
 
     @JsonComponent
-    public static class CustomerJsonSerializer extends JsonSerializer<CustomerDTO> {
+    public static class CustomerJsonSerializer extends JsonSerializerWithAccessFilter<CustomerDTO> {
-
-        private final ApplicationContext ctx;
 
         public CustomerJsonSerializer(final ApplicationContext ctx) {
-            this.ctx = ctx;
+            super(ctx);
-        }
-
-        @Override
-        public void serialize(final CustomerDTO customerDTO, final JsonGenerator jsonGenerator,
-                              final SerializerProvider serializerProvider) throws IOException {
-
-           new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, serializerProvider, customerDTO).serialize();
         }
     }
 
     @JsonComponent
-    public static class CustomerJsonDeserializer extends JsonDeserializer<CustomerDTO> {
+    public static class CustomerJsonDeserializer extends JsonDeserializerWithAccessFilter<CustomerDTO> {
-
-        private final ApplicationContext ctx;
 
         public CustomerJsonDeserializer(final ApplicationContext ctx) {
-            this.ctx = ctx;
+            super(ctx);
-        }
-
-        @Override
-        public CustomerDTO deserialize(final JsonParser jsonParser,
-                                       final DeserializationContext deserializationContext) {
-
-            return new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, deserializationContext, CustomerDTO.class).deserialize();
         }
     }
 }

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

@@ -1,16 +1,19 @@
 package org.hostsharing.hsadminng.service.util;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
 
 public class ReflectionUtil {
 
-    public static <T> void setValue(final T dto, final String fieldName, final Object value) {
+    public static Field getField(final Class<?> aClass, final String fieldName) {
         try {
-            final Field field = dto.getClass().getDeclaredField(fieldName);
+            return aClass.getDeclaredField(fieldName);
-            field.setAccessible(true);
+        } catch (final NoSuchFieldException e) {
-            field.set(dto, value);
+            if (aClass.getSuperclass() != Object.class) {
-        } catch (NoSuchFieldException | IllegalAccessException e) {
+                return getField(aClass.getSuperclass(), fieldName);
-            throw new RuntimeException(e);
+            }
+            throw new IllegalArgumentException(e);
         }
     }
 
@@ -18,20 +21,81 @@ public class ReflectionUtil {
         try {
             field.setAccessible(true);
             field.set(dto, value);
-        } catch (IllegalAccessException e) {
+        } catch (final IllegalAccessException e) {
             throw new RuntimeException(e);
         }
     }
 
-    public static <T> T getValue(final T dto, final Field field) {
+    @SuppressWarnings("unchecked")
+    public static <T, R> R getValue(final T dto, final Field field) {
         try {
             field.setAccessible(true);
-            return (T) field.get(dto);
+            return (R) field.get(dto);
-        } catch (IllegalAccessException e) {
+        } catch (final IllegalAccessException e) {
             throw new RuntimeException(e);
         }
     }
 
+    /**
+     * Searches the annotations of 'clazz' for an implemented interface 'rawInterface' and returns the class of the actual generics parameter at the specified index.
+     *
+     * @param clazz        a class which implements the generic interface 'rawInterface'
+     * @param rawInterface a generic interface
+     * @param paramIndex   the index of the generics parameter within 'rawInterface'
+     * @param <T>          the expected class of the generics parameter at position 'index' in 'rawInterface'
+     * @return the actual generics parameter
+     */
+    @SuppressWarnings("unchecked")
+    public static <T> Class<T> determineGenericInterfaceParameter(final Class<?> clazz, final Class<?> rawInterface, final int paramIndex) {
+        for (Type genericInterface : clazz.getGenericInterfaces()) {
+            if (genericInterface instanceof ParameterizedType) {
+                final ParameterizedType parameterizedType = (ParameterizedType) genericInterface;
+                if (parameterizedType.getRawType() == rawInterface) {
+                    return (Class<T>) parameterizedType.getActualTypeArguments()[paramIndex];
+                }
+            }
+        }
+        if (clazz.getSuperclass() != Object.class) {
+            return determineGenericInterfaceParameter(clazz.getSuperclass(), rawInterface, paramIndex);
+        }
+        for (Class<?> implementedInterface : clazz.getInterfaces()) {
+            final Class<T> found = determineGenericInterfaceParameter(implementedInterface, rawInterface, paramIndex);
+            if (found != null) {
+                return found;
+            }
+        }
+        throw new AssertionError(clazz.getSimpleName() + " expected to implement " + rawInterface.getSimpleName() + "<...>");
+    }
+
+    /**
+     * Searches the annotations of 'clazz' for an extended class 'rawClass' and returns the class of the actual generics parameter at the specified index.
+     *
+     * @param clazz      a class which implements the generic interface 'rawClass'
+     * @param rawClass   a generic class
+     * @param paramIndex the index of the generics parameter within 'rawClass'
+     * @param <T>        the expected class of the generics parameter at position 'index' in 'rawClass'
+     * @return the actual generics parameter
+     */
+    @SuppressWarnings("unchecked")
+    public static <T> Class<T> determineGenericClassParameter(final Class<?> clazz, final Class<?> rawClass, final int paramIndex) {
+        final Type genericClass = clazz.getGenericSuperclass();
+        if (genericClass instanceof ParameterizedType) {
+            final ParameterizedType parameterizedType = (ParameterizedType) genericClass;
+            if (parameterizedType.getRawType() == rawClass) {
+                return (Class<T>) parameterizedType.getActualTypeArguments()[paramIndex];
+            }
+        }
+        if (clazz.getSuperclass() != Object.class) {
+            return determineGenericClassParameter(clazz.getSuperclass(), rawClass, paramIndex);
+        }
+        throw new AssertionError(clazz.getSimpleName() + " expected to extend " + rawClass.getSimpleName() + "<...>");
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <E extends Enum<E>> Enum<E> asEnumValue(final Class<?> type, final Object value) {
+        return Enum.valueOf((Class<E>) type, value.toString());
+    }
+
     @FunctionalInterface
     public interface ThrowingSupplier<T> {
         T get() throws Exception;
@@ -40,7 +104,7 @@ public class ReflectionUtil {
     public static <T> T unchecked(final ThrowingSupplier<T> supplier) {
         try {
             return supplier.get();
-        } catch (Exception e) {
+        } catch (final Exception e) {
             throw new RuntimeException(e);
         }
     }

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

@@ -32,7 +32,7 @@ import static org.hostsharing.hsadminng.service.accessfilter.MockSecurityContext
 import static org.mockito.BDDMockito.given;
 
 @SuppressWarnings("ALL")
-public class JSonDeserializerWithAccessFilterUnitTest {
+public class JSonDeserializationWithAccessFilterUnitTest {
 
     @Rule
     public MockitoRule mockitoRule = MockitoJUnit.rule();
@@ -98,7 +98,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
             ImmutablePair.of("openStringField", null)));
 
         // when
-        GivenDto actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
+        GivenDto actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
 
         // then
         assertThat(actualDto.openStringField).isNull();
@@ -113,7 +113,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
             ImmutablePair.of("openStringField", "String Value")));
 
         // when
-        GivenDto actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
+        GivenDto actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
 
         // then
         assertThat(actualDto.openStringField).isEqualTo("String Value");
@@ -128,7 +128,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
             ImmutablePair.of("openIntegerField", 1234)));
 
         // when
-        GivenDto actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
+        GivenDto actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
 
         // then
         assertThat(actualDto.openIntegerField).isEqualTo(1234);
@@ -157,7 +157,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         );
 
         // when
-        GivenDto actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
+        GivenDto actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
 
         // then
         assertThat(actualDto.openIntegerField).isEqualTo(11);
@@ -183,7 +183,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         );
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOf(NotImplementedException.class);
@@ -200,7 +200,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
             ImmutablePair.of("restrictedField", "update value of restricted field")));
 
         // when
-        GivenDto actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
+        GivenDto actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
 
         // then
         assertThat(actualDto.restrictedField).isEqualTo("update value of restricted field");
@@ -217,7 +217,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
             ImmutablePair.of("restrictedField", "initial value of restricted field")));
 
         // when
-        GivenDto actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
+        GivenDto actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize();
 
         // then
         assertThat(actualDto.restrictedField).isEqualTo("initial value of restricted field");
@@ -234,7 +234,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         );
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOfSatisfying(BadRequestAlertException.class, badRequestAlertException -> {
@@ -254,7 +254,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         );
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOfSatisfying(BadRequestAlertException.class, badRequestAlertException -> {
@@ -273,7 +273,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         );
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenChildDto.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenChildDto.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOfSatisfying(BadRequestAlertException.class, badRequestAlertException -> {
@@ -292,7 +292,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         );
 
         // when
-        final GivenChildDto actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenChildDto.class).deserialize();
+        final GivenChildDto actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenChildDto.class).deserialize();
 
         // then
         assertThat(actualDto.parentId).isEqualTo(1234L);
@@ -309,7 +309,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
             ImmutablePair.of("restrictedField", "Restricted String Value")));
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDto.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOfSatisfying(BadRequestAlertException.class, badRequestAlertException -> {
@@ -324,7 +324,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         givenJSonTree(asJSon(ImmutablePair.of("id", 1111L)));
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDtoWithMultipleSelfId.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDtoWithMultipleSelfId.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOf(AssertionError.class).hasMessage("multiple @SelfId detected in GivenDtoWithMultipleSelfId");
@@ -338,7 +338,7 @@ public class JSonDeserializerWithAccessFilterUnitTest {
         givenJSonTree(asJSon(ImmutablePair.of("unknown", new Arbitrary())));
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, GivenDtoWithUnknownFieldType.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, GivenDtoWithUnknownFieldType.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOf(NotImplementedException.class)

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

@@ -21,7 +21,7 @@ import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
 
-public class JSonSerializerWithAccessFilterUnitTest {
+public class JSonSerializationWithAccessFilterUnitTest {
 
     @Rule
     public MockitoRule mockitoRule = MockitoJUnit.rule();
@@ -55,7 +55,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializeStringField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeStringField("openStringField", givenDTO.openStringField);
@@ -64,7 +64,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializeIntegerField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeNumberField("openIntegerField", givenDTO.openIntegerField);
@@ -73,7 +73,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializePrimitiveIntField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeNumberField("openPrimitiveIntField", givenDTO.openPrimitiveIntField);
@@ -82,7 +82,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializeLongField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeNumberField("openLongField", givenDTO.openLongField);
@@ -91,7 +91,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializePrimitiveLongField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeNumberField("openPrimitiveLongField", givenDTO.openPrimitiveLongField);
@@ -100,7 +100,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializeBooleanField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeBooleanField("openBooleanField", givenDTO.openBooleanField);
@@ -109,7 +109,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializePrimitiveBooleanField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeBooleanField("openPrimitiveBooleanField", givenDTO.openPrimitiveBooleanField);
@@ -118,7 +118,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializeBigDecimalField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeNumberField("openBigDecimalField", givenDTO.openBigDecimalField);
@@ -127,7 +127,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializeLocalDateField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeStringField("openLocalDateField", givenDTO.openLocalDateFieldAsString);
@@ -136,7 +136,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
     @Test
     public void shouldSerializeEnumField() throws IOException {
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeStringField("openEnumField", givenDTO.openEnumFieldAsString);
@@ -150,7 +150,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
         MockSecurityContext.givenUserHavingRole(GivenCustomerDto.class, 888L, Role.FINANCIAL_CONTACT);
 
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeStringField("restrictedField", givenDTO.restrictedField);
@@ -164,7 +164,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
         MockSecurityContext.givenUserHavingRole(GivenCustomerDto.class, 888L, Role.ANY_CUSTOMER_USER);
 
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator, never()).writeStringField("restrictedField", givenDTO.restrictedField);
@@ -183,7 +183,7 @@ public class JSonSerializerWithAccessFilterUnitTest {
         final GivenDtoWithUnimplementedFieldType givenDtoWithUnimplementedFieldType = new GivenDtoWithUnimplementedFieldType();
 
         // when
-        final Throwable actual = catchThrowable(() -> new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDtoWithUnimplementedFieldType).serialize());
+        final Throwable actual = catchThrowable(() -> new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDtoWithUnimplementedFieldType).serialize());
 
         // then
         assertThat(actual).isInstanceOf(NotImplementedException.class);

src/test/java/org/hostsharing/hsadminng/service/dto/MembershipDTOUnitTest.java

@@ -7,7 +7,7 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import org.apache.commons.lang3.tuple.ImmutablePair;
 import org.hostsharing.hsadminng.service.CustomerService;
 import org.hostsharing.hsadminng.service.MembershipService;
-import org.hostsharing.hsadminng.service.accessfilter.JSonDeserializerWithAccessFilter;
+import org.hostsharing.hsadminng.service.accessfilter.JSonDeserializationWithAccessFilter;
 import org.hostsharing.hsadminng.service.accessfilter.Role;
 import org.hostsharing.hsadminng.web.rest.errors.BadRequestAlertException;
 import org.junit.Before;
@@ -74,7 +74,7 @@ public class MembershipDTOUnitTest {
         givenJSonTree(asJSon(ImmutablePair.of("customerId", 1234L)));
 
         // when
-        final MembershipDTO actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, MembershipDTO.class).deserialize();
+        final MembershipDTO actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, MembershipDTO.class).deserialize();
 
         // then
         assertThat(actualDto.getCustomerId()).isEqualTo(1234L);
@@ -87,7 +87,7 @@ public class MembershipDTOUnitTest {
         givenJSonTree(asJSon(ImmutablePair.of("customerId", 1234L)));
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, MembershipDTO.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, MembershipDTO.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOfSatisfying(BadRequestAlertException.class, badRequestAlertException -> {

src/test/java/org/hostsharing/hsadminng/service/dto/ShareDTOUnitTest.java

@@ -9,8 +9,8 @@ import org.apache.commons.lang3.tuple.ImmutablePair;
 import org.hostsharing.hsadminng.domain.enumeration.ShareAction;
 import org.hostsharing.hsadminng.service.CustomerService;
 import org.hostsharing.hsadminng.service.MembershipService;
-import org.hostsharing.hsadminng.service.accessfilter.JSonDeserializerWithAccessFilter;
+import org.hostsharing.hsadminng.service.accessfilter.JSonDeserializationWithAccessFilter;
-import org.hostsharing.hsadminng.service.accessfilter.JSonSerializerWithAccessFilter;
+import org.hostsharing.hsadminng.service.accessfilter.JSonSerializationWithAccessFilter;
 import org.hostsharing.hsadminng.service.accessfilter.Role;
 import org.hostsharing.hsadminng.web.rest.errors.BadRequestAlertException;
 import org.junit.Before;
@@ -89,7 +89,7 @@ public class ShareDTOUnitTest {
         givenJSonTree(asJSon(ImmutablePair.of("membershipId", SOME_MEMBERSHIP_ID)));
 
         // when
-        final ShareDTO actualDto = new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, ShareDTO.class).deserialize();
+        final ShareDTO actualDto = new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, ShareDTO.class).deserialize();
 
         // then
         assertThat(actualDto.getMembershipId()).isEqualTo(SOME_MEMBERSHIP_ID);
@@ -102,7 +102,7 @@ public class ShareDTOUnitTest {
         givenJSonTree(asJSon(ImmutablePair.of("membershipId", ShareDTOUnitTest.SOME_MEMBERSHIP_ID)));
 
         // when
-        Throwable exception = catchThrowable(() -> new JSonDeserializerWithAccessFilter<>(ctx, jsonParser, null, ShareDTO.class).deserialize());
+        Throwable exception = catchThrowable(() -> new JSonDeserializationWithAccessFilter<>(ctx, jsonParser, null, ShareDTO.class).deserialize());
 
         // then
         assertThat(exception).isInstanceOfSatisfying(BadRequestAlertException.class, badRequestAlertException -> {
@@ -118,7 +118,7 @@ public class ShareDTOUnitTest {
         final ShareDTO givenDTO = createShareDto();
 
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeNumberField("id", givenDTO.getId());
@@ -133,7 +133,7 @@ public class ShareDTOUnitTest {
         final ShareDTO givenDTO = createShareDto();
 
         // when
-        new JSonSerializerWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
+        new JSonSerializationWithAccessFilter<>(ctx, jsonGenerator, null, givenDTO).serialize();
 
         // then
         verify(jsonGenerator).writeNumberField("id", givenDTO.getId());

src/test/java/org/hostsharing/hsadminng/service/util/ReflectionUtilTest.java

@@ -0,0 +1,129 @@
+package org.hostsharing.hsadminng.service.util;
+
+import org.junit.Test;
+
+import java.awt.*;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.ThrowableAssert.catchThrowable;
+import static org.hostsharing.hsadminng.service.util.ReflectionUtil.unchecked;
+
+
+public class ReflectionUtilTest {
+
+    @Test
+    public void setValue() {
+        final TestDto dto = new TestDto(5);
+        ReflectionUtil.setValue(dto, ReflectionUtil.getField(dto.getClass(), "intVal"), 77);
+        assertThat(dto.intVal).isEqualTo(77);
+    }
+
+    @Test
+    public void setValueViaSuperclass() {
+        final SubTestDto dto = new SubTestDto(5);
+        ReflectionUtil.setValue(dto, ReflectionUtil.getField(dto.getClass(), "intVal"), 77);
+        assertThat(dto.intVal).isEqualTo(77);
+    }
+
+    @Test
+    public void getValue() {
+        final TestDto dto = new TestDto(5);
+        final int actual = ReflectionUtil.getValue(dto, ReflectionUtil.getField(dto.getClass(), "intVal"));
+        assertThat(actual).isEqualTo(5);
+    }
+
+    @Test
+    public void getValueViaSuperclass() {
+        final SubTestDto dto = new SubTestDto(5);
+        final int actual = ReflectionUtil.getValue(dto, ReflectionUtil.getField(dto.getClass(), "intVal"));
+        assertThat(actual).isEqualTo(5);
+    }
+
+    @Test
+    public void determineGenericInterfaceParameteDirect() {
+        Class<?> actual = ReflectionUtil.determineGenericInterfaceParameter(SuperClass.class, GenericInterface.class, 1);
+        assertThat(actual).isEqualTo(Long.class);
+    }
+
+    @Test
+    public void determineGenericInterfaceParameterViaSuperclass() {
+        Class<?> actual = ReflectionUtil.determineGenericInterfaceParameter(SomeClass.class, GenericInterface.class, 1);
+        assertThat(actual).isEqualTo(Long.class);
+    }
+
+    @Test
+    public void throwsExceptionIfGenericInterfaceNotImplemented() {
+        final Throwable actual = catchThrowable(() -> ReflectionUtil.determineGenericInterfaceParameter(SomeClass.class, UnusedGenericInterface.class, 1));
+        assertThat(actual).isInstanceOf(AssertionError.class).hasMessageContaining("GenericClass expected to implement UnusedGenericInterface<...>");
+    }
+
+    @Test
+    public void determineGenericClassParameterDirect() {
+        Class<?> actual = ReflectionUtil.determineGenericClassParameter(SuperClass.class, GenericClass.class, 1);
+        assertThat(actual).isEqualTo(Boolean.class);
+    }
+
+    @Test
+    public void determineGenericClassParameterViaSuperclss() {
+        Class<?> actual = ReflectionUtil.determineGenericClassParameter(SomeClass.class, GenericClass.class, 1);
+        assertThat(actual).isEqualTo(Boolean.class);
+    }
+
+    @Test
+    public void throwsExceptionIfGenericClassNotExended() {
+        final Throwable actual = catchThrowable(() -> ReflectionUtil.determineGenericClassParameter(SomeClass.class, UnusedSuperClass.class, 1));
+        assertThat(actual).isInstanceOf(AssertionError.class).hasMessageContaining("GenericClass expected to extend UnusedSuperClass<...>");
+    }
+
+    @Test
+    public void uncheckedRethrowsCheckedException() {
+        final Exception givenException = new Exception("Checked Test Exception");
+        final Throwable actual = catchThrowable(() -> unchecked(() -> {
+            throw givenException;
+        }));
+        assertThat(actual).isInstanceOfSatisfying(RuntimeException.class, rte ->
+            assertThat(rte.getCause()).isSameAs(givenException)
+        );
+    }
+
+    @Test
+    public void asEnumValue() {
+        assertThat(ReflectionUtil.asEnumValue(Color.class, "RED")).isEqualTo(Color.RED);
+    }
+
+    // --- only test fixture below ---
+
+    private static class TestDto {
+        int intVal;
+
+        TestDto(final int intval) {
+            this.intVal = intval;
+        }
+    }
+
+    private static class SubTestDto extends TestDto {
+
+        SubTestDto(final int intval) {
+            super(intval);
+        }
+    }
+
+    private static class SomeClass extends SuperClass {
+    }
+
+    private static class SuperClass extends GenericClass<String, Boolean> implements GenericInterface<Integer, Long> {
+    }
+
+
+    private static class UnusedSuperClass extends GenericClass<String, Boolean> implements GenericInterface<Integer, Long> {
+    }
+
+    private static class GenericClass<T, V> {
+    }
+
+    private interface GenericInterface<T, V> {
+    }
+
+    private interface UnusedGenericInterface<T, V> {
+    }
+}