/*** HiveStoragePredicateHandler is an optional companion to {@link* HiveStorageHandler}; it should only be implemented by handlers which* support decomposition of predicates being pushed down into table scans.*/
public interface HiveStoragePredicateHandler {/*** Gives the storage handler a chance to decompose a predicate.  The storage* handler should analyze the predicate and return the portion of it which* cannot be evaluated during table access.  For example, if the original* predicate is <code>x = 2 AND upper(y)='YUM'</code>, the storage handler* might be able to handle <code>x = 2</code> but leave the "residual"* <code>upper(y)='YUM'</code> for Hive to deal with.  The breakdown* need not be non-overlapping; for example, given the* predicate <code>x LIKE 'a%b'</code>, the storage handler might* be able to evaluate the prefix search <code>x LIKE 'a%'</code>, leaving* <code>x LIKE '%b'</code> as the residual.** @param jobConf contains a job configuration matching the one that* will later be passed to getRecordReader and getSplits** @param deserializer deserializer which will be used when* fetching rows** @param predicate predicate to be decomposed** @return decomposed form of predicate, or null if no pushdown is* possible at all*/public DecomposedPredicate decomposePredicate(JobConf jobConf,Deserializer deserializer,ExprNodeDesc predicate);/*** Struct class for returning multiple values from decomposePredicate.*/public static class DecomposedPredicate {/*** Portion of predicate to be evaluated by storage handler.  Hive* will pass this into the storage handler's input format.*/public ExprNodeGenericFuncDesc pushedPredicate;/*** Serialized format for filter*/public Serializable pushedPredicateObject;/*** Portion of predicate to be post-evaluated by Hive for any rows* which are returned by storage handler.*/public ExprNodeGenericFuncDesc residualPredicate;}
}