private void assertPublicMethod(Method method) {
        int modifiers = method.getModifiers();
        if (!Modifier.isPublic(modifiers)) {
            throw new IllegalArgumentException("Event handler method [" + method + "] must be public.");
        }
    }
A event listener that invokes a target object's method that accepts a single event argument.

@since 1.3
event/src/main/java/org/apache/shiro/event/support/SingleArgumentMethodEventListener.java