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From Robert Evans <ev...@yahoo-inc.com>
Subject Re: API Design: getClusterMetrics
Date Wed, 10 Oct 2012 14:30:31 GMT
Sapsi,

I am not positive on this but I think the reason for this is to future
proof the API.  If in the future we want to add in new optional
parameters, I believe that it is impossible in protocol buffers without
having that request object. I could be wrong I am not an expert on PB.

--Bobby Evans

On 10/9/12 11:11 PM, "Saptarshi Guha" <saptarshi.guha@gmail.com> wrote:

>Hello
>(sorry for cross post)
>I am reading the DistributedShell code and came across
>
> GetClusterMetricsRequest clusterMetricsReq =
>Records.newRecord(GetClusterMetricsRequest.class);
> GetClusterMetricsResponse clusterMetricsResp =
>applicationsManager.getClusterMetrics(clusterMetricsReq);
>
>In the page: 
>http://hadoop.apache.org/docs/current/api/org/apache/hadoop/yarn/api/Clien
>tRMProtocol.html#getClusterMetrics%28org.apache.hadoop.yarn.api.protocolre
>cords.GetClusterMetricsRequest%29
>
>I can't find any other function getClusterMetrics.
>
>Why was the choice made to pass a GetClusterMetricsRequest object to
>getClusterMetrics?
>why couldn't the programmer invoke
>applicationsManager.getClusterMetrics() and the method would reply
>with a GetClusterMetricsResponse?
>
>Regards
>Sapsi
>(P.S I havent used YARN or even written code with it, i'm just reading
>some sources and my reading is incomplete, so apologies if this comes
>across
>as stupid)


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