extract any enum type parameters correctly

Signed-off-by: Daniel Kraschewski <daniel.kraschewski@tngtech.com>
TNG · Nov 28, 2020 · 68fb6ad · 68fb6ad
1 parent 772c171
commit 68fb6ad
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Showing 6 changed files with 103 additions and 20 deletions.
diff --git a/src/main/java/com/tngtech/configbuilder/util/EnumTypeExtractor.java b/src/main/java/com/tngtech/configbuilder/util/EnumTypeExtractor.java
@@ -0,0 +1,23 @@
+package com.tngtech.configbuilder.util;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.stream.Stream;
+
+import static java.util.Arrays.stream;
+
+public class EnumTypeExtractor {
+
+    Stream<Class<? extends Enum<?>>> getEnumTypesRelevantFor(Type type) {
+        if (type instanceof Class && ((Class<?>) type).isEnum()) {
+            return Stream.of((Class<? extends Enum<?>>) type);
+        }
+        if (type instanceof ParameterizedType) {
+            ParameterizedType parameterizedType = (ParameterizedType) type;
+            return stream(parameterizedType.getActualTypeArguments())
+                    .flatMap(this::getEnumTypesRelevantFor)
+                    .distinct();
+        }
+        return Stream.empty();
+    }
+}
diff --git a/src/main/java/com/tngtech/configbuilder/util/FieldValueTransformer.java b/src/main/java/com/tngtech/configbuilder/util/FieldValueTransformer.java
@@ -20,6 +20,7 @@ public class FieldValueTransformer {
     private final ConfigBuilderFactory configBuilderFactory;
     private final ErrorMessageSetup errorMessageSetup;
     private final GenericsAndCastingHelper genericsAndCastingHelper;
+    private final EnumTypeExtractor enumTypeExtractor;
     private Object[] additionalOptions;
 
     //Order is important: Prefer List over Set if both apply!
@@ -38,6 +39,7 @@ public FieldValueTransformer(ConfigBuilderFactory configBuilderFactory) {
         this.configBuilderFactory = configBuilderFactory;
         this.errorMessageSetup = configBuilderFactory.getInstance(ErrorMessageSetup.class);
         this.genericsAndCastingHelper = configBuilderFactory.getInstance(GenericsAndCastingHelper.class);
+        this.enumTypeExtractor = configBuilderFactory.getInstance(EnumTypeExtractor.class);
     }
 
     public Object transformFieldValue(Field field, Object sourceValue) {
@@ -51,9 +53,9 @@ private void initialize(Field field) {
         for(Class<? extends TypeTransformer> transformerClass : getAllTransformers(field)) {
             availableTransformers.add(configBuilderFactory.getInstance(transformerClass));
         }
-        genericsAndCastingHelper.getEnumTypeOrParameterIfApplicable(field)
-                .map(StringToEnumTypeTransformer::new)
-                .ifPresent(availableTransformers::add);
+        enumTypeExtractor.getEnumTypesRelevantFor(field.getGenericType())
+                .map(enumClass -> new StringToEnumTypeTransformer(enumClass))
+                .forEach(availableTransformers::add);
 
         additionalOptions = field.isAnnotationPresent(Separator.class)? new Object[]{field.getAnnotation(Separator.class).value()} : new Object[]{","};
     }

diff --git a/src/main/java/com/tngtech/configbuilder/util/GenericsAndCastingHelper.java b/src/main/java/com/tngtech/configbuilder/util/GenericsAndCastingHelper.java
@@ -2,12 +2,10 @@
 
 import com.google.common.collect.ImmutableMap;
 
-import java.lang.reflect.Field;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.Collection;
 import java.util.Map;
-import java.util.Optional;
 
 public class GenericsAndCastingHelper {
 
@@ -62,19 +60,4 @@ else if(Collection.class.isAssignableFrom((Class<?>)((ParameterizedType)targetTy
     public boolean isPrimitiveOrWrapper(Class targetClass) {
         return primitiveToWrapperMapping.containsKey(targetClass) || primitiveToWrapperMapping.containsValue(targetClass);
     }
-
-    public <E extends Enum<E>> Optional<Class<E>> getEnumTypeOrParameterIfApplicable(Field field) {
-        if (field.getType().isEnum()) {
-            return Optional.of((Class<E>) field.getType());
-        }
-
-        if (!Collection.class.isAssignableFrom(field.getType())) {
-            return Optional.empty();
-        }
-
-        Type collectionParameterType = ((ParameterizedType) field.getGenericType()).getActualTypeArguments()[0];
-        return collectionParameterType instanceof Class && ((Class<?>) collectionParameterType).isEnum()
-               ? Optional.of((Class<E>) collectionParameterType)
-               : Optional.empty();
-    }
 }
diff --git a/src/test/java/com/tngtech/configbuilder/util/EnumTypeExtractorTest.java b/src/test/java/com/tngtech/configbuilder/util/EnumTypeExtractorTest.java
@@ -0,0 +1,71 @@
+package com.tngtech.configbuilder.util;
+
+import org.junit.Test;
+
+import java.lang.reflect.Field;
+import java.util.List;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class EnumTypeExtractorTest {
+
+    enum TestEnum1 {}
+
+    enum TestEnum2 {}
+
+    public static class TestClass {
+
+        String simpleNonEnumField;
+        Map<Integer, String> nonEnumParameterizedField;
+
+        TestEnum1 simpleEnumField;
+        Map<TestEnum1, TestEnum2> fieldWithEnumTypeParameters;
+        Map<TestEnum1, List<TestEnum2>> fieldWithNestedEnumTypeParameters;
+        Map<TestEnum1, Map<TestEnum1, TestEnum1>> fieldWithRepeatedEnumTypeParameter;
+    }
+
+    private final EnumTypeExtractor enumTypeExtractor = new EnumTypeExtractor();
+
+    @Test
+    public void testExtractionOnSimpleNonEnumType() throws Exception {
+        Field simpleNonEnumField = TestClass.class.getDeclaredField("simpleNonEnumField");
+        assertThat(enumTypeExtractor.getEnumTypesRelevantFor(simpleNonEnumField.getGenericType()))
+                .isEmpty();
+    }
+
+    @Test
+    public void testExtractionOnNonEnumParameterizedType() throws Exception {
+        Field nonEnumParameterizedField = TestClass.class.getDeclaredField("nonEnumParameterizedField");
+        assertThat(enumTypeExtractor.getEnumTypesRelevantFor(nonEnumParameterizedField.getGenericType()))
+                .isEmpty();
+    }
+
+    @Test
+    public void testExtractionOfSimpleEnumType() throws Exception {
+        Field simpleEnumField = TestClass.class.getDeclaredField("simpleEnumField");
+        assertThat(enumTypeExtractor.getEnumTypesRelevantFor(simpleEnumField.getGenericType()))
+                .containsExactly(TestEnum1.class);
+    }
+
+    @Test
+    public void testExtractionOfEnumTypeParameters() throws Exception {
+        Field fieldWithEnumTypeParameters = TestClass.class.getDeclaredField("fieldWithEnumTypeParameters");
+        assertThat(enumTypeExtractor.getEnumTypesRelevantFor(fieldWithEnumTypeParameters.getGenericType()))
+                .containsExactlyInAnyOrder(TestEnum1.class, TestEnum2.class);
+    }
+
+    @Test
+    public void testExtractionOfNestedEnumTypeParameters() throws Exception {
+        Field fieldWithNestedEnumTypeParameters = TestClass.class.getDeclaredField("fieldWithNestedEnumTypeParameters");
+        assertThat(enumTypeExtractor.getEnumTypesRelevantFor(fieldWithNestedEnumTypeParameters.getGenericType()))
+                .containsExactlyInAnyOrder(TestEnum1.class, TestEnum2.class);
+    }
+
+    @Test
+    public void testExtractedEnumTypesAreDeduplicated() throws Exception {
+        Field fieldWithRepeatedEnumTypeParameter = TestClass.class.getDeclaredField("fieldWithRepeatedEnumTypeParameter");
+        assertThat(enumTypeExtractor.getEnumTypesRelevantFor(fieldWithRepeatedEnumTypeParameter.getGenericType()))
+                .containsExactly(TestEnum1.class);
+    }
+}
diff --git a/src/test/java/com/tngtech/configbuilder/util/FieldValueTransformerComponentTest.java b/src/test/java/com/tngtech/configbuilder/util/FieldValueTransformerComponentTest.java
@@ -77,6 +77,7 @@ private static class TestConfigClass {
     public void setUp() throws Exception {
         when(configBuilderFactory.getInstance(ErrorMessageSetup.class)).thenReturn(errorMessageSetup);
         when(configBuilderFactory.getInstance(GenericsAndCastingHelper.class)).thenReturn(new GenericsAndCastingHelper());
+        when(configBuilderFactory.getInstance(EnumTypeExtractor.class)).thenReturn(new EnumTypeExtractor());
 
         when(configBuilderFactory.getInstance(CharacterSeparatedStringToStringListTransformer.class)).thenReturn(new CharacterSeparatedStringToStringListTransformer());
         when(configBuilderFactory.getInstance(CharacterSeparatedStringToStringSetTransformer.class)).thenReturn(new CharacterSeparatedStringToStringSetTransformer());

diff --git a/src/test/java/com/tngtech/configbuilder/util/FieldValueTransformerTest.java b/src/test/java/com/tngtech/configbuilder/util/FieldValueTransformerTest.java
@@ -36,6 +36,8 @@ public class FieldValueTransformerTest {
     @Mock
     private GenericsAndCastingHelper genericsAndCastingHelper;
     @Mock
+    private EnumTypeExtractor enumTypeExtractor;
+    @Mock
     private CollectionToArrayListTransformer collectionToArrayListTransformer;
     @Mock
     private CharacterSeparatedStringToStringListTransformer characterSeparatedStringToStringListTransformer;
@@ -59,6 +61,7 @@ public class FieldValueTransformerTest {
     public void setUp() throws Exception {
         when(configBuilderFactory.getInstance(ErrorMessageSetup.class)).thenReturn(errorMessageSetup);
         when(configBuilderFactory.getInstance(GenericsAndCastingHelper.class)).thenReturn(genericsAndCastingHelper);
+        when(configBuilderFactory.getInstance(EnumTypeExtractor.class)).thenReturn(enumTypeExtractor);
 
         fieldValueTransformer = new FieldValueTransformer(configBuilderFactory);
         field = this.getClass().getDeclaredField("testField");