org.drools.core.base.evaluators

Class OverlapsEvaluatorDefinition

java.lang.Object

org.drools.core.base.evaluators.OverlapsEvaluatorDefinition

All Implemented Interfaces:

Externalizable, Serializable, org.kie.api.runtime.rule.EvaluatorDefinition

public class OverlapsEvaluatorDefinition
extends Object
implements EvaluatorDefinition

The implementation of the overlaps evaluator definition.

The overlaps evaluator correlates two events and matches when the current event starts before the correlated event starts and finishes after the correlated event starts, but before the correlated event finishes. In other words, both events have an overlapping period.

Lets look at an example:

$eventA : EventA( this overlaps $eventB )

The previous pattern will match if and only if:

 $eventA.startTimestamp < $eventB.startTimestamp < $eventA.endTimestamp < $eventB.endTimestamp 

The overlaps operator accepts 1 or 2 optional parameters as follow:

• If one parameter is defined, this will be the maximum distance between the start timestamp of the correlated event and the end timestamp of the current event. Example:

$eventA : EventA( this overlaps[ 5s ] $eventB )

Will match if and only if:

 
 $eventA.startTimestamp < $eventB.startTimestamp < $eventA.endTimestamp < $eventB.endTimestamp &&
 0 <= $eventA.endTimestamp - $eventB.startTimestamp <= 5s 
 

• If two values are defined, the first value will be the minimum distance and the second value will be the maximum distance between the start timestamp of the correlated event and the end timestamp of the current event. Example:

$eventA : EventA( this overlaps[ 5s, 10s ] $eventB )

Will match if and only if:

 
 $eventA.startTimestamp < $eventB.startTimestamp < $eventA.endTimestamp < $eventB.endTimestamp &&
 5s <= $eventA.endTimestamp - $eventB.startTimestamp <= 10s 
 

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	OverlapsEvaluatorDefinition.OverlapsEvaluator Implements the 'overlaps' evaluator itself

Nested classes/interfaces inherited from interface org.drools.core.base.evaluators.EvaluatorDefinition

EvaluatorDefinition.Target

Field Summary

Fields

Modifier and Type	Field and Description
static Operator	OVERLAPS
static Operator	OVERLAPS_NOT
static String	overlapsOp

Constructor Summary

Constructors

Constructor and Description
OverlapsEvaluatorDefinition()

Method Summary

Modifier and Type	Method and Description
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)

Methods inherited from class java.lang.Object

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

Field Detail

overlapsOp

public static final String overlapsOp

See Also:

Constant Field Values

OVERLAPS

public static Operator OVERLAPS

OVERLAPS_NOT

public static Operator OVERLAPS_NOT

Constructor Detail

OverlapsEvaluatorDefinition

public OverlapsEvaluatorDefinition()

Method Detail

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

getEvaluator

public Evaluator getEvaluator(ValueType type,
                              Operator operator)

Description copied from interface: EvaluatorDefinition

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

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

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

getEvaluator

public Evaluator getEvaluator(ValueType type,
                              Operator operator,
                              String parameterText)

Description copied from interface: EvaluatorDefinition

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

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

parameterText - some evaluators support parameters and these parameters are defined as a String that is parsed by the evaluator itself.

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

getEvaluator

public Evaluator getEvaluator(ValueType type,
                              String operatorId,
                              boolean isNegated,
                              String parameterText)

Description copied from interface: EvaluatorDefinition

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

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 evaluator

isNegated - 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.

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

getEvaluator

public Evaluator getEvaluator(ValueType type,
                              String operatorId,
                              boolean isNegated,
                              String parameterText,
                              EvaluatorDefinition.Target left,
                              EvaluatorDefinition.Target right)

Description copied from interface: EvaluatorDefinition

Returns the evaluator instance for the given type and the defined parameterText

Parameters:

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 evaluator

isNegated - 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.

Returns:

an Evaluator instance capable of evaluating expressions between values of the given type, or null in case the type is not supported.

getEvaluatorIds

public String[] getEvaluatorIds()

Description copied from interface: EvaluatorDefinition

Returns the list of identifies this evaluator implementation supports

Returns:

isNegatable

public boolean isNegatable()

Description copied from interface: EvaluatorDefinition

My apologies to English speakers if the word "negatable" does not exist. :) This method returns true if this evaluator supports negation. Example: the "matches" operator supports "not matches" and so is "negatable" (!?)

Returns:

getTarget

public EvaluatorDefinition.Target getTarget()

Description copied from interface: EvaluatorDefinition

There are evaluators that operate on *fact* attributes, evaluators that operate on *fact handle* attributes, and evaluators that operate on both. This method returns the target of the current evaluator.

Returns:

true if this evaluator operates on fact handle attributes and false if it operates on fact attributes

supportsType

public boolean supportsType(ValueType type)

Description copied from interface: EvaluatorDefinition

Returns true in case this evaluator supports operations over values of that specific type.

Returns: