Package org.drools.mvel.evaluators

Class BeforeEvaluatorDefinition

  • All Implemented Interfaces:
    java.io.Externalizable, java.io.Serializable, org.drools.compiler.rule.builder.EvaluatorDefinition, org.kie.api.runtime.rule.EvaluatorDefinition
    public class BeforeEvaluatorDefinition
extends java.lang.Object
implements org.drools.compiler.rule.builder.EvaluatorDefinition

    The implementation of the 'before' evaluator definition.

    The before evaluator correlates two events and matches when the temporal distance from the event being correlated to the current correlated belongs to the distance range declared for the operator.

    Lets look at an example:

    $eventA : EventA( this before[ 3m30s, 4m ] $eventB )

    The previous pattern will match if and only if the temporal distance between the time when $eventA finished and the time when $eventB started is between ( 3 minutes and 30 seconds ) and ( 4 minutes ). In other words:

     3m30s <= $eventB.startTimestamp - $eventA.endTimeStamp <= 4m

    The temporal distance interval for the before operator is optional:

    • If two values are defined (like in the example below), the interval starts on the first value and finishes on the second.
    • If only one value is defined, then the interval starts on the value and finishes on the positive infinity.
    • If no value is defined, it is assumed that the initial value is 1ms and the final value is the positive infinity.

    NOTE: it is allowed to define negative distances for this operator. Example:

    $eventA : EventA( this before[ -3m30s, -2m ] $eventB )

    NOTE: if the initial value is greater than the finish value, the engine automatically reverse them, as there is no reason to have the initial value greater than the finish value. Example: the following two patterns are considered to have the same semantics:

     $eventA : EventA( this before[ -3m30s, -2m ] $eventB )
 $eventA : EventA( this before[ -2m, -3m30s ] $eventB )
    See Also:
    Serialized Form

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  BeforeEvaluatorDefinition.BeforeEvaluator
      Implements the 'before' evaluator itself

      • Nested classes/interfaces inherited from interface org.drools.compiler.rule.builder.EvaluatorDefinition

        org.drools.compiler.rule.builder.EvaluatorDefinition.Target

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static org.drools.drl.parser.impl.Operator BEFORE  
      static java.lang.String beforeOp  
      static org.drools.drl.parser.impl.Operator NOT_BEFORE  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type, java.lang.String operatorId, boolean isNegated, java.lang.String parameterText)  
      org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type, java.lang.String operatorId, boolean isNegated, java.lang.String parameterText, org.drools.compiler.rule.builder.EvaluatorDefinition.Target left, org.drools.compiler.rule.builder.EvaluatorDefinition.Target right)  
      org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type, org.drools.drl.parser.impl.Operator operator)  
      org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type, org.drools.drl.parser.impl.Operator operator, java.lang.String parameterText)  
      java.lang.String[] getEvaluatorIds()  
      org.drools.compiler.rule.builder.EvaluatorDefinition.Target getTarget()  
      boolean isNegatable()  
      void readExternal​(java.io.ObjectInput in)  
      boolean supportsType​(org.drools.base.base.ValueType type)  
      void writeExternal​(java.io.ObjectOutput out)  

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • beforeOp

        public static final java.lang.String beforeOp

      • BEFORE

        public static final org.drools.drl.parser.impl.Operator BEFORE

      • NOT_BEFORE

        public static final org.drools.drl.parser.impl.Operator NOT_BEFORE

    • Constructor Detail

      • BeforeEvaluatorDefinition

        public BeforeEvaluatorDefinition()

    • Method Detail

      • readExternal

        public void readExternal​(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException
        Specified by:
        readExternal in interface java.io.Externalizable
        Throws:
        java.io.IOException
        java.lang.ClassNotFoundException

      • writeExternal

        public void writeExternal​(java.io.ObjectOutput out)
                   throws java.io.IOException
        Specified by:
        writeExternal in interface java.io.Externalizable
        Throws:
        java.io.IOException

      • getEvaluator

        public org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type,
                                                            org.drools.drl.parser.impl.Operator operator)
        Specified by:
        getEvaluator in interface org.drools.compiler.rule.builder.EvaluatorDefinition

      • getEvaluator

        public org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type,
                                                            org.drools.drl.parser.impl.Operator operator,
                                                            java.lang.String parameterText)
        Specified by:
        getEvaluator in interface org.drools.compiler.rule.builder.EvaluatorDefinition

      • getEvaluator

        public org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type,
                                                            java.lang.String operatorId,
                                                            boolean isNegated,
                                                            java.lang.String parameterText)
        Specified by:
        getEvaluator in interface org.drools.compiler.rule.builder.EvaluatorDefinition

      • getEvaluator

        public org.drools.base.rule.accessor.Evaluator getEvaluator​(org.drools.base.base.ValueType type,
                                                            java.lang.String operatorId,
                                                            boolean isNegated,
                                                            java.lang.String parameterText,
                                                            org.drools.compiler.rule.builder.EvaluatorDefinition.Target left,
                                                            org.drools.compiler.rule.builder.EvaluatorDefinition.Target right)
        Specified by:
        getEvaluator in interface org.drools.compiler.rule.builder.EvaluatorDefinition

      • getEvaluatorIds

        public java.lang.String[] getEvaluatorIds()
        Specified by:
        getEvaluatorIds in interface org.drools.compiler.rule.builder.EvaluatorDefinition

      • isNegatable

        public boolean isNegatable()
        Specified by:
        isNegatable in interface org.drools.compiler.rule.builder.EvaluatorDefinition

      • getTarget

        public org.drools.compiler.rule.builder.EvaluatorDefinition.Target getTarget()
        Specified by:
        getTarget in interface org.drools.compiler.rule.builder.EvaluatorDefinition

      • supportsType

        public boolean supportsType​(org.drools.base.base.ValueType type)
        Specified by:
        supportsType in interface org.drools.compiler.rule.builder.EvaluatorDefinition