enforce arg name to be present

Author: ttmunyunguma

dev/io.openliberty.mcp.internal/src/io/openliberty/mcp/internal/ToolMetadata.java

@@ -51,17 +51,38 @@ public static ToolMetadata createFrom(Tool annotation, Bean<?> bean, AnnotatedMe
 
     private static Map<String, ArgumentMetadata> getArgumentMap(AnnotatedMethod<?> method) {
         Map<String, ArgumentMetadata> result = new HashMap<>();
-        for (AnnotatedParameter<?> p : method.getParameters()) {
-            ToolArg pInfo = p.getAnnotation(ToolArg.class);
-            if (pInfo != null) {
-                String toolArgName = (pInfo.name().equals(ToolArg.ELEMENT_NAME)) ? p.getJavaParameter().getName() : pInfo.name(); // p.getJavaParameter().getName() needs java compiler -parameter flag to work
-                boolean isDuplicateArg = result.containsKey(toolArgName);
-                result.put(toolArgName, new ArgumentMetadata(p.getBaseType(), p.getPosition(), pInfo.description(), pInfo.required(), isDuplicateArg));
+
+        for (AnnotatedParameter<?> param : method.getParameters()) {
+
+            ToolArg argAnnotation = param.getAnnotation(ToolArg.class);
+
+            if (argAnnotation == null) {
+                continue;
             }
+
+            String argName = resolveArgumentName(param, argAnnotation);
+            boolean isDuplicateArg = result.containsKey(argName);
+
+            result.put(argName, new ArgumentMetadata(param.getBaseType(),
+                                                     param.getPosition(),
+                                                     argAnnotation.description(),
+                                                     argAnnotation.required(),
+                                                     isDuplicateArg));
         }
         return result.isEmpty() ? Collections.emptyMap() : result;
     }
 
+    private static String resolveArgumentName(AnnotatedParameter<?> param, ToolArg argAnnotation) {
+        if (ToolArg.ELEMENT_NAME.equals(argAnnotation.name())) {
+            return argAnnotation.name();
+        }
+        if (param.getJavaParameter().isNamePresent()) {
+            // needs java compiler -parameter flag to work
+            return param.getJavaParameter().getName();
+        }
+        throw new IllegalStateException("Parameter name not set. Ensure that javac -parameter flag is enabled");
+    }
+
     private static List<SpecialArgumentMetadata> getSpecialArgumentList(AnnotatedMethod<?> method) {
         List<SpecialArgumentMetadata> result = new ArrayList<>();
         for (AnnotatedParameter<?> p : method.getParameters()) {