org.optaplanner.core.impl.score.stream.drools.common

Interface DroolsMetadata<LogicalFactType,GenuineFactType>

Type Parameters:

LogicalFactType - The actual type of the fact in the current rule.

GenuineFactType - The original type of the fact, in the original genuine rule.

All Known Implementing Classes:

DroolsGenuineMetadata, DroolsInferredMetadata

public interface DroolsMetadata<LogicalFactType,GenuineFactType>

Represents a variable on the left-hand side of a rule. This variable can either be genuine or logical.

Genuine variables look like this:

$a: SomeFact()

$b: SomeOtherFact()

Logical variables look like this:

LogicalTuple($a: getItem(0), $b: getItem(1))

Genuine variables become logical variables through an operation of logical insertion, which might look like this:

     rule "Rule with genuine facts"
     when
          $a: SomeFact()
          $b: SomeOtherFact()
     then
          insertLogical(new LogicalTuple($a, $b));
     end

     rule "Rule with an inferred fact"
     when
          LogicalTuple($a: getItem(0), $b: getItem(1))
     then
          // some consequence
     end
 

This class is an abstraction, allowing code to read variables of both types.

Method Summary

Modifier and Type	Method and Description
org.drools.model.PatternDSL.PatternDef<LogicalFactType>	buildPattern() A pattern is a way of accessing the variable in Drools.
GenuineFactType	extract(LogicalFactType container) Extract variable value from the rule.
org.drools.model.Declaration<LogicalFactType>	getVariableDeclaration()
static <A> DroolsGenuineMetadata<A>	ofGenuine(org.drools.model.Declaration<A> variableDeclaration)
static <A> DroolsInferredMetadata<A>	ofInferred(org.drools.model.Declaration<DroolsLogicalTuple> variableDeclaration, Supplier<org.drools.model.PatternDSL.PatternDef<DroolsLogicalTuple>> patternBuilder)
static <A> DroolsInferredMetadata<A>	ofInferred(org.drools.model.Declaration<DroolsLogicalTuple> variableDeclaration, Supplier<org.drools.model.PatternDSL.PatternDef<DroolsLogicalTuple>> patternBuilder, int itemId)
DroolsMetadata<LogicalFactType,GenuineFactType>	substitute(Supplier<org.drools.model.PatternDSL.PatternDef<LogicalFactType>> patternBuilder) Create new DroolsMetadata, where its pattern will be different.

Method Detail

ofInferred

static <A> DroolsInferredMetadata<A> ofInferred(org.drools.model.Declaration<DroolsLogicalTuple> variableDeclaration,
                                                Supplier<org.drools.model.PatternDSL.PatternDef<DroolsLogicalTuple>> patternBuilder)

ofInferred

static <A> DroolsInferredMetadata<A> ofInferred(org.drools.model.Declaration<DroolsLogicalTuple> variableDeclaration,
                                                Supplier<org.drools.model.PatternDSL.PatternDef<DroolsLogicalTuple>> patternBuilder,
                                                int itemId)

ofGenuine

static <A> DroolsGenuineMetadata<A> ofGenuine(org.drools.model.Declaration<A> variableDeclaration)

extract

GenuineFactType extract(LogicalFactType container)

Extract variable value from the rule. For genuine variables, this will be equivalent to Function.identity(). For inferred variables, this will refer to the DroolsLogicalTuple.getItem(int).

Parameters:

container - the variable from Drools on which to operate

Returns:

value of the variable

getVariableDeclaration

org.drools.model.Declaration<LogicalFactType> getVariableDeclaration()

buildPattern

org.drools.model.PatternDSL.PatternDef<LogicalFactType> buildPattern()

A pattern is a way of accessing the variable in Drools. In some rules, patterns may be reused for several different constructs. Drools does not support reuse of pattern instances for different uses, and therefore we must create new ones every time we want to use them.

Returns:

pattern to give access to the variable

substitute

DroolsMetadata<LogicalFactType,GenuineFactType> substitute(Supplier<org.drools.model.PatternDSL.PatternDef<LogicalFactType>> patternBuilder)

Create new DroolsMetadata, where its pattern will be different.

Parameters:

patternBuilder - the new pattern to be returned by buildPattern(). Typically reuses the parent pattern with some modifications.

Returns:

New instance of DroolsMetadata.