Get Entity (Read) in service implementation in gateway service builder

Hi,

while giving entity set in request url as (/sap/opu/odata/sap/ZSAMPLE_CREATE1_SRV/xxxxxset)  executing in gateway client an error occurs with 501 status code as <message xml:lang="en">Method 'FORREADSET_GET_ENTITYSET' not implemented in data provider class.</message>.

I have implemented the entity set too,still i am getting the same issue.Can any one sort out this and given an clear idea about service implementation topic.

Thanks,

Lakshmi Ramsai P.