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java.lang.Objectorg.drools.base.evaluators.CoincidesEvaluatorDefinition
public class CoincidesEvaluatorDefinition
The implementation of the 'coincides' evaluator definition.
The coincides
evaluator correlates two events and matches when both
happen at the same time. Optionally, the evaluator accept thresholds for the distance between
events' start and finish timestamps.
Lets look at an example:
$eventA : EventA( this coincides $eventB )
The previous pattern will match if and only if the start timestamps of both $eventA and $eventB are the same AND the end timestamp of both $eventA and $eventB also are the same.
Optionally, this operator accepts one or two parameters. These parameters are the thresholds for the distance between matching timestamps. If only one paratemer is given, it is used for both start and end timestamps. If two parameters are given, then the first is used as a threshold for the start timestamp and the second one is used as a threshold for the end timestamp. In other words:
$eventA : EventA( this coincides[15s, 10s] $eventB )Above pattern will match if and only if:
abs( $eventA.startTimestamp - $eventB.startTimestamp ) <= 15s && abs( $eventA.endTimestamp - $eventB.endTimestamp ) <= 10s
NOTE: it makes no sense to use negative interval values for the parameters and the engine will raise an error if that happens.
Nested Class Summary | |
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static class |
CoincidesEvaluatorDefinition.CoincidesEvaluator
Implements the 'coincides' evaluator itself |
Nested classes/interfaces inherited from interface org.drools.base.evaluators.EvaluatorDefinition |
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EvaluatorDefinition.Target |
Field Summary | |
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static Operator |
COINCIDES
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static Operator |
COINCIDES_NOT
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Constructor Summary | |
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CoincidesEvaluatorDefinition()
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Method Summary | |
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Evaluator |
getEvaluator(ValueType type,
Operator operator)
Returns the evaluator instance for the given type and the defined parameterText |
Evaluator |
getEvaluator(ValueType type,
Operator operator,
String parameterText)
Returns the evaluator instance for the given type and the defined parameterText |
Evaluator |
getEvaluator(ValueType type,
String operatorId,
boolean isNegated,
String parameterText)
Returns the evaluator instance for the given type and the defined parameterText |
Evaluator |
getEvaluator(ValueType type,
String operatorId,
boolean isNegated,
String parameterText,
EvaluatorDefinition.Target left,
EvaluatorDefinition.Target right)
Returns the evaluator instance for the given type and the defined parameterText |
String[] |
getEvaluatorIds()
Returns the list of identifies this evaluator implementation supports |
EvaluatorDefinition.Target |
getTarget()
There are evaluators that operate on *fact* attributes, evaluators that operate on *fact handle* attributes, and evaluators that operate on both. |
boolean |
isNegatable()
My apologies to English speakers if the word "negatable" does not exist. :) This method returns true if this evaluator supports negation. |
void |
readExternal(ObjectInput in)
|
boolean |
supportsType(ValueType type)
Returns true in case this evaluator supports operations over values of that specific type. |
void |
writeExternal(ObjectOutput out)
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Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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public static final Operator COINCIDES
public static final Operator COINCIDES_NOT
Constructor Detail |
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public CoincidesEvaluatorDefinition()
Method Detail |
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public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
readExternal
in interface Externalizable
IOException
ClassNotFoundException
public void writeExternal(ObjectOutput out) throws IOException
writeExternal
in interface Externalizable
IOException
public Evaluator getEvaluator(ValueType type, Operator operator)
EvaluatorDefinition
type
- the type of the attributes this evaluator will
operate on. This is important because the evaluator
may do optimisations and type coercion based on the
types it is evaluating. It is also possible that
this evaluator does not support a given type.operator
- the operator implemented by the evaluator
public Evaluator getEvaluator(ValueType type, Operator operator, String parameterText)
EvaluatorDefinition
type
- the type of the attributes this evaluator will
operate on. This is important because the evaluator
may do optimisations and type coercion based on the
types it is evaluating. It is also possible that
this evaluator does not support a given type.operator
- the operator implemented by the evaluatorparameterText
- some evaluators support parameters and these
parameters are defined as a String that is
parsed by the evaluator itself.
public Evaluator getEvaluator(ValueType type, String operatorId, boolean isNegated, String parameterText)
EvaluatorDefinition
type
- the type of the attributes this evaluator will
operate on. This is important because the evaluator
may do optimisations and type coercion based on the
types it is evaluating. It is also possible that
this evaluator does not support a given type.operatorId
- the string identifier of the evaluatorisNegated
- true if the evaluator instance to be returned is
the negated version of the evaluator.parameterText
- some evaluators support parameters and these
parameters are defined as a String that is
parsed by the evaluator itself.
public Evaluator getEvaluator(ValueType type, String operatorId, boolean isNegated, String parameterText, EvaluatorDefinition.Target left, EvaluatorDefinition.Target right)
EvaluatorDefinition
type
- the type of the attributes this evaluator will
operate on. This is important because the evaluator
may do optimisations and type coercion based on the
types it is evaluating. It is also possible that
this evaluator does not support a given type.operatorId
- the string identifier of the evaluatorisNegated
- true if the evaluator instance to be returned is
the negated version of the evaluator.parameterText
- some evaluators support parameters and these
parameters are defined as a String that is
parsed by the evaluator itself.left
- the target of the evaluator on the Left side,
i.e., on Rete terms, the previous binding or
the actual value on the right side of the operator.right
- the target of the evaluator on the Right side,
i.e., on Rete terms, the current pattern field.
public String[] getEvaluatorIds()
EvaluatorDefinition
public boolean isNegatable()
EvaluatorDefinition
public EvaluatorDefinition.Target getTarget()
EvaluatorDefinition
public boolean supportsType(ValueType type)
EvaluatorDefinition
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