public void onEvent(Object event) {
        Method method = getMethod();
        try {
            method.invoke(getTarget(), event);
        } catch (Exception e) {
            throw new IllegalStateException("Unable to invoke event handler method [" + method + "].", e);
        }
    }
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