com.redhat.lightblue.assoc

Interface QueryPlanIterator

All Known Implementing Classes:

BruteForceQueryPlanIterator, First

public interface QueryPlanIterator

Iterates over possible query plans by rearranging the query plan graph. The given query plan is taken as an initial state. Every successive call to next will modify the query plan into a unique tree. Once all possible query plans are iterated, next returns false.

Method Summary

Modifier and Type	Method and Description
boolean	next() Modifies the query plan into a unique tree.
void	reset(QueryPlan p) Resets the query plan iterator with the given copy of the query plan.

Method Detail

reset

void reset(QueryPlan p)

Resets the query plan iterator with the given copy of the query plan. The query iterator must assume that this given query plan is in its initial state, and should iterate through different query plans, modifying the given copy.

next

boolean next()

Modifies the query plan into a unique tree.

Returns:

If true, tne query plan is configured into a unique tree. If false, query plan is now returned back to its original state during iterator construction, and the iteration is expected to stop.