public void setHandler(AnnotationHandler handler) {
        this.handler = handler;
    }
Sets the {@code AnnotationHandler} used to perform authorization behavior based on
an annotation discovered at runtime.

@param handler the {@code AnnotationHandler} used to perform authorization behavior based on
               an annotation discovered at runtime.
core/src/main/java/org/apache/shiro/aop/AnnotationMethodInterceptor.java