public void basicParameterValidation(String name, String description, String namespace)
            throws AnnotationValidationException {
        //Check if the @Extension name is empty.
        if (name.isEmpty()) {
            throw new AnnotationValidationException(MessageFormat.format("The @Extension -> name " +
                    " annotated in class {0} is null or empty.", extensionClassFullName));
        }
        //Check if the @Extension description is empty.
        if (description.isEmpty()) {
            throw new AnnotationValidationException(MessageFormat.format("The @Extension -> description " +
                    "annotated in class {0} is null or empty.", extensionClassFullName));
        }
        //Check if the @Extension namespace is empty.
        if (namespace.isEmpty()) {
            //The namespace cannot be null or empty if @Extension is not in core package.
            //Extract core package name by using CORE_PACKAGE_PATTERN pattern.
            if (!CORE_PACKAGE_PATTERN.matcher(extensionClassFullName).find()) {
                throw new AnnotationValidationException(MessageFormat.format("The @Extension -> namespace " +
                        "annotated in class {0} is null or empty.", extensionClassFullName));
            }
        }
    }
Basic @Extension annotation elements validation.

@param name        name of the @Extension which needs to be validate.
@param description description of the @Extension  which needs to be validate.
@param namespace   namespace of the @Extension  which needs to be validate.
@throws AnnotationValidationException whenever if the validate rule violate, throws the annotation validate
                                      exception with proper message.
modules/siddhi-annotations/src/main/java/io/siddhi/annotation/processor/AbstractAnnotationProcessor.java