✨ Enable plugin lookup for Java classes in classpath

Previously, plugins had to be packaged as JARs to be discovered.
This change allows plugins to be loaded from Java classes present in the classpath.

Additionally, performed minor refactoring, including adding @OverRide annotations
and updating Javadoc.

Author: ujibang

.gitignore

@@ -287,3 +287,5 @@ $RECYCLE.BIN/
 # infer- http://fbinfer.com/
 infer-out
 /commons/nbproject/
+
+rebel.xml

commons/src/main/java/org/restheart/metrics/Metrics.java

@@ -121,7 +121,7 @@ public static void xffValueRIndex(int ridx) {
     }
 
 
-    private static AttachmentKey<List<MetricLabel>> CUSTOM_METRIC_LABELS = AttachmentKey.create(List.class);
+    private static final AttachmentKey<List<MetricLabel>> CUSTOM_METRIC_LABELS = AttachmentKey.create(List.class);
 
     /**
      * attach metrics labels to request
@@ -141,7 +141,7 @@ public static void attachMetricLabels(Request<?> request, List<MetricLabel> labe
      * RequestsMetricsCollector adds labels to the collected metrics
      *
      * @param request
-     * @param labels
+     * @param label
      */
     public static void attachMetricLabel(Request<?> request, MetricLabel label) {
         var labels = new ArrayList<MetricLabel>();
@@ -153,7 +153,7 @@ public static void attachMetricLabel(Request<?> request, MetricLabel label) {
      * retrives the metrics labels attached to request
      *
      * @param request
-     * @param labels
+     * @return
      */
     public static List<MetricLabel> getMetricLabels(Request<?> request) {
         return request.getExchange().getAttachment(CUSTOM_METRIC_LABELS);

core/src/main/java/org/restheart/plugins/PluginsScanner.java

@@ -386,17 +386,18 @@ public RuntimeClassGraph() {
                     .map(path -> path.getFileName().toString())
                     .toArray(String[]::new);
 
-            this.classGraph = new ClassGraph().disableModuleScanning().disableDirScanning()
-                    .disableNestedJarScanning()
-                    .disableRuntimeInvisibleAnnotations()
-                    .addClassLoader(PluginsClassloader.getInstance())
-                    .addClassLoader(ClassLoader.getSystemClassLoader())
-                    .rejectJars(libJars) // avoids scanning lib jars
-                    .enableAnnotationInfo()
-                    .enableMethodInfo()
-                    .enableFieldInfo()
-                    .ignoreFieldVisibility()
-                    .initializeLoadedClasses();
+            this.classGraph = new ClassGraph()
+                .disableModuleScanning()
+                .disableNestedJarScanning()
+                .disableRuntimeInvisibleAnnotations()
+                .addClassLoader(PluginsClassloader.getInstance())
+                .addClassLoader(ClassLoader.getSystemClassLoader())
+                .rejectJars(libJars) // avoids scanning lib jars
+                .enableAnnotationInfo()
+                .enableMethodInfo()
+                .enableFieldInfo()
+                .ignoreFieldVisibility()
+                .initializeLoadedClasses();
         }
 
         private long starScanTime = 0;

core/src/main/java/org/restheart/providers/RHConfigurationProvider.java

@@ -29,6 +29,7 @@
 
 @RegisterPlugin(name = "rh-config", description = "provides the RESTHeart configuration")
 public class RHConfigurationProvider implements Provider<Configuration> {
+    @Override
     public Configuration get(PluginRecord<?> caller) {
         return Bootstrapper.getConfiguration();
     }