improved javadoc (#2239)

Author: rrayst

core/src/main/java/com/predic8/membrane/core/interceptor/oauth2client/OAuth2Resource2Interceptor.java

@@ -44,6 +44,10 @@
 /**
  * @description Allows only authorized HTTP requests to pass through. Unauthorized requests get a redirect to the
  * authorization server as response.
+ *
+ * This interceptor does Session Management and can thereby translate Session IDs to OAuth2/OIDC Access Tokens.
+ *
+ * Beyond regular OIDC-compliant authorization servers, this interceptor can also be used with Azure B2C.
  * @topic 3. Security and Validation
  */
 @MCElement(name = "oauth2Resource2")

core/src/main/java/com/predic8/membrane/core/interceptor/opentelemetry/OpenTelemetryInterceptor.java

@@ -51,6 +51,13 @@
 import static io.opentelemetry.api.trace.StatusCode.OK;
 import static io.opentelemetry.context.Context.current;
 
+/**
+ * @description Creates an OpenTelemetry span for each HTTP request passing through. Sends the tracing data to the
+ * speficied OpenTelemetry collector.
+ *
+ * See also examples/monitoring-tracing/opentelemetry for a demo, including screenshots.
+ * @topic 4. Monitoring, Logging and Statistics
+ */
 @MCElement(name = "openTelemetry")
 public class OpenTelemetryInterceptor extends AbstractInterceptor {
     private double sampleRate = 1.0;

core/src/main/java/com/predic8/membrane/core/interceptor/prometheus/PrometheusInterceptor.java

@@ -40,6 +40,12 @@
 import static com.predic8.membrane.core.openapi.util.Utils.joinByComma;
 import static java.util.stream.Collectors.toList;
 
+/**
+ * @description Exposes some of Membrane's internal metrics in the Prometheus format.
+ *
+ * See also examples/monitoring-tracing/prometheus for a demo, including a screenshot.
+ * @topic 4. Monitoring, Logging and Statistics
+ */
 @MCElement(name = "prometheus")
 public class PrometheusInterceptor extends AbstractInterceptor {