implemented LinkEnricher registration via Enrich annotation

scm-webapp/src/main/java/sonia/scm/api/v2/resources/LinkEnricherAutoRegistration.java

@@ -0,0 +1,45 @@
+package sonia.scm.api.v2.resources;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import sonia.scm.plugin.Extension;
+
+import javax.inject.Inject;
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
+import java.util.Set;
+
+/**
+ * Registers every {@link LinkEnricher} which is annotated with an {@link Enrich} annotation.
+ */
+@Extension
+public class LinkEnricherAutoRegistration implements ServletContextListener {
+
+  private static final Logger LOG = LoggerFactory.getLogger(LinkEnricherAutoRegistration.class);
+
+  private final LinkEnricherRegistry registry;
+  private final Set<LinkEnricher> enrichers;
+
+  @Inject
+  public LinkEnricherAutoRegistration(LinkEnricherRegistry registry, Set<LinkEnricher> enrichers) {
+    this.registry = registry;
+    this.enrichers = enrichers;
+  }
+
+  @Override
+  public void contextInitialized(ServletContextEvent sce) {
+    for (LinkEnricher enricher : enrichers) {
+      Enrich annotation = enricher.getClass().getAnnotation(Enrich.class);
+      if (annotation != null) {
+        registry.register(annotation.value(), enricher);
+      } else {
+        LOG.warn("found LinkEnricher extension {} without Enrich annotation", enricher.getClass());
+      }
+    }
+  }
+
+  @Override
+  public void contextDestroyed(ServletContextEvent sce) {
+    // nothing todo
+  }
+}