Package org.drools.mvel.evaluators

Class MeetsEvaluatorDefinition

java.lang.Object
org.drools.mvel.evaluators.MeetsEvaluatorDefinition
All Implemented Interfaces:
Externalizable, Serializable, EvaluatorDefinition, EvaluatorDefinition
public class MeetsEvaluatorDefinition extends Object implements EvaluatorDefinition

The implementation of the meets evaluator definition.

The meets evaluator correlates two events and matches when the current event's end timestamp happens at the same time as the correlated event's start timestamp.

Lets look at an example:

$eventA : EventA( this meets $eventB )

The previous pattern will match if and only if the $eventA finishes at the same time $eventB starts. In other words:

 
 abs( $eventB.startTimestamp - $eventA.endTimestamp ) == 0

The meets evaluator accepts one optional parameter. If it is defined, it determines the maximum distance between the end timestamp of current event and the start timestamp of the correlated event in order for the operator to match. Example:

$eventA : EventA( this meets[ 5s ] $eventB )
Will match if and only if: 
 
 abs( $eventB.startTimestamp - $eventA.endTimestamp) <= 5s

NOTE: it makes no sense to use a negative interval value for the parameter and the engine will raise an exception if that happens.

See Also: