Small refactoring to suggestion and some docs

components/inspectit-ocelot-configurationserver/src/main/java/rocks/inspectit/ocelot/rest/yamlhighlighter/HighlightRulesMapController.java

@@ -14,10 +14,11 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.ParameterizedType;
-import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 @RestController
 public class HighlightRulesMapController extends AbstractBaseController {
@@ -64,16 +65,26 @@ public class HighlightRulesMapController extends AbstractBaseController {
     @VisibleForTesting
     static final String KEY_OBJECT_ATTRIBUTES = "object-attributes";
 
+    /**
+     * Generates a Map that describes the structure of a class, as of now only used with {@link InspectitConfig},
+     * and its fields recursively for usage in Syntax Highlighting in the config-server UI.
+     *
+     * @param currentClass The class whose fields should be described.
+     *
+     * @return A Map describing the structure of the class.
+     */
     @VisibleForTesting
     Map<String, Object> generateMap(Class<?> currentClass) {
         Map<String, Object> currentClassMap = new HashMap<>();
 
         ReflectionUtils.doWithFields(currentClass, field -> {
 
+            // Static fields are ignored, since they are not configured in the UI.
             if (Modifier.isStatic(field.getModifiers())) {
                 return;
             }
 
+            // Create new map that will contain the data for the current field.
             Map<String, Object> innerMap = new HashMap<>();
 
             if (field.getType().equals(java.util.Map.class)) {
@@ -93,25 +104,28 @@ Map<String, Object> generateMap(Class<?> currentClass) {
                 generateMapCollections(innerMap, listContentType, KEY_LIST_CONTENT_TYPE, KEY_LIST_CONTENTS);
 
             } else if (field.getType().equals(java.lang.Object.class)) {
-
+                // If the field is an Object, we can not make any assumptions about its contents and
+                // instead any arbitrary YAML will be allowed in the highlighting.
                 innerMap.put(KEY_TYPE, VALUE_TYPE_YAML);
 
             } else if (field.getType().isEnum()) {
+
                 innerMap.put(KEY_TYPE, VALUE_TYPE_ENUM);
                 innerMap.put(KEY_ENUM_VALUES, extractEnumValues(field.getType()));
 
             } else if (field.getType().getName().startsWith("rocks.inspectit.ocelot.config.model")) {
-
+                // If the field is of a class of this project, this method will be called again recursively to describe
+                // the contents of that class as well.
                 innerMap.put(KEY_TYPE, VALUE_TYPE_OBJECT);
                 innerMap.put(KEY_OBJECT_ATTRIBUTES, generateMap(field.getType()));
 
             } else if (currentClass.equals(GenericActionSettings.class) && (field.getName()
                     .equals("value") || field.getName().equals("valueBody"))) {
-
+                // These two fields contain a special kind of String, i.e. Java code, so they get a special type for highlighting.
                 innerMap.put(KEY_TYPE, VALUE_TYPE_JAVA);
 
             } else {
-
+                // If the field is of any other class, any contents will simply be highlighted as text.
                 innerMap.put(KEY_TYPE, VALUE_TYPE_TEXT);
 
             }
@@ -121,6 +135,15 @@ Map<String, Object> generateMap(Class<?> currentClass) {
         return currentClassMap;
     }
 
+    /**
+     * Helper function for {@link this#generateMap} to set contents for collections in the described classes,
+     * i.e. Lists or Maps. Works analogous to {@link this#generateMap}.
+     *
+     * @param innerMap       The inner map created in {@link this#generateMap} for the current field.
+     * @param contentType    The type of the values of the Collection.
+     * @param keyContentType Key for the content-type in the generated map, e.g. KEY_MAP_CONTENT_TYPE.
+     * @param keyContents    Key for the contents in the generated map, e.g. KEY_MAP_CONTENTS.
+     */
     private void generateMapCollections(Map<String, Object> innerMap, Class<?> contentType, String keyContentType, String keyContents) {
         if (contentType.equals(Object.class)) {
             innerMap.put(keyContentType, VALUE_TYPE_YAML);
@@ -135,12 +158,15 @@ private void generateMapCollections(Map<String, Object> innerMap, Class<?> conte
         }
     }
 
+    /**
+     * Returns a list of names of all possible values for the given enum.
+     *
+     * @param currentEnum Enum whose values should be returned.
+     *
+     * @return List of names of all possible values for the enum.
+     */
     private List<String> extractEnumValues(Class<?> currentEnum) {
-        List<String> enumValues = new ArrayList<>();
-        for (Field enumField : currentEnum.getFields()) {
-            enumValues.add(enumField.getName());
-        }
-        return enumValues;
+        return Arrays.stream(currentEnum.getFields()).map(Field::getName).collect(Collectors.toList());
     }
 
     @ApiOperation(value = "Get JSON for Highlight Rules Generation", notes = "")