add javadoc

independent-projects/resteasy-reactive/common/processor/src/main/java/org/jboss/resteasy/reactive/common/processor/EndpointIndexer.java

@@ -1216,6 +1216,26 @@ private static String appendPath(String prefix, String suffix) {
 
     protected abstract PARAM createIndexedParam();
 
+    /**
+     * Analyzes an endpoint parameter and encapsulates its details into a `PARAM` object.
+     *
+     * <p>Steps performed:</p>
+     * <ul>
+     *   <li><b>Initialization:</b> Creates a `PARAM` object with basic information about the class, method, and annotations.</li>
+     *   <li><b>Parameter type identification:</b> Retrieves annotations like `@PathParam`, `@QueryParam`, `@FormParam`, etc.
+     *       If multiple such annotations are present, an error is thrown. The parameter type is set accordingly.</li>
+     *   <li><b>Special processing based on type:</b> Handles collections (`List`, `Set`, `Map`, `Optional`) differently
+     *       and applies specific rules for `byte[]`, `SseEventSink`, and `AsyncResponse`.</li>
+     *   <li><b>Conversion and compatibility:</b> Searches for registered converters if the parameter is convertible,
+     *       configuring handlers for lists, maps, or primitive types.</li>
+     *   <li><b>Finalization:</b> Determines if the parameter is single or multiple. If it does not match previous cases,
+     *       it is treated as the request body (`@Body`).</li>
+     * </ul>
+     *
+     * <p>In short, this method identifies, classifies, and configures an endpoint parameter,
+     * ensuring proper conversion and handling.</p>
+     */
+
     public PARAM extractParameterInfo(ClassInfo currentClassInfo, ClassInfo actualEndpointInfo,
             MethodInfo currentMethodInfo, Map<String, String> existingConverters, AdditionalReaders additionalReaders,
             Map<DotName, AnnotationInstance> anns, Type paramType, String errorLocation, Object[] errorLocationParameters,