protected void setAnnotationClass(Class<? extends Annotation> annotationClass)
            throws IllegalArgumentException {
        if (annotationClass == null) {
            String msg = "annotationClass argument cannot be null";
            throw new IllegalArgumentException(msg);
        }
        this.annotationClass = annotationClass;
    }
Sets the type of annotation this handler will inspect and process.

@param annotationClass the type of annotation this handler will process.
@throws IllegalArgumentException if the argument is <code>null</code>.
core/src/main/java/org/apache/shiro/aop/AnnotationHandler.java