class CacheFilter implements Filter {

    @Override
    public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
        if (cacheFactory != null && ConfigUtils.isNotEmpty(invoker.getUrl().getMethodParameter(invocation.getMethodName(), Constants.CACHE_KEY))) {
            Cache cache = cacheFactory.getCache(invoker.getUrl(), invocation);
            if (cache != null) {
                String key = StringUtils.toArgumentString(invocation.getArguments());
                Object value = cache.get(key);
                if (value != null) {
                    return new RpcResult(value);
                }
                Result result = invoker.invoke(invocation);
                if (!result.hasException() && result.getValue() != null) {
                    cache.put(key, result.getValue());
                }
                return result;
            }
        }
        return invoker.invoke(invocation);
    }

}