This patch allows a third party to inject their own frontend
class instead of using the default JniFrontend included in the
project.
The test case includes an interface that runs queries as normal
except for the "select 1" query which gets changed to "select 42".
Change-Id: I89e677da557b39232847644b6ff17510e2b3c3d5
Reviewed-on: http://gerrit.cloudera.org:8080/20459
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
