Interface NodeMatcher

test/org/apache/pig/test/utils/dotGraph/NodeMatcher.java:33–48

This is a common interface for graph vertex mapping logic. Though I call it Matcher so that people don't get confused with mapper in MapReduce.

 */

public interface NodeMatcher<E extends Operator,
                             P extends OperatorPlan<E>> {

    /***
     * This method does matching between vertices in two
     * given plans.
     *
     * @param plan1
     * @param plan2
     * @param messages
     * @return The output map: plan1Key -> plan2Key
     */
    Map<OperatorKey, OperatorKey> match(P plan1,
                                        P plan2,
                                        StringBuilder messages) ;
}