package sjdb;

/**

* This is an interface for a visitor class that performs a depth-first,

* left-to-right traversal of a query plan.

* @author nmg

*/

public interface PlanVisitor {

/**

* Visit a Scan operator.

* @param op Scan operator to be visited

*/

public void visit(Scan op);

/**

* Visit a Project operator.

* @param op Project operator to be visited

*/

public void visit(Project op);

/**

* Visit a Select operator.

* @param op Select operator to be visited

*/

public void visit(Select op);

/**

* Visit a Product operator.

* @param op Product operator to be visited

*/

public void visit(Product op);

/**

*

* @param op

*/

public void visit(Join op);

}