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

## Class UniLeftHandSide<A>

- java.lang.Object
- - org.optaplanner.core.impl.score.stream.drools.common.UniLeftHandSide<A>

- Type Parameters:
    `A` - generic type of the resulting variable
  All Implemented Interfaces:
    `Supplier<List<org.drools.model.view.ViewItem<?>>>`

      public final class UniLeftHandSide<A>
      extends Object

  Represents the left-hand side of a Drools rule, the result of which is a single variable. The simplest variant of such rule, with no filters or groupBys applied, would look like this in equivalent DRL:

        rule "Simplest univariate rule"
        when
            $a: Something()
        then
            // Do something with the $a variable.
        end

  Left-hand side is that part of the rule between the "when" and "then" keywords. The part between the "then" and "end" keywords is called the consequence of the rule, and this class does not represent it. It can be created by calling `andTerminate()`. There are also more complex variants of rules that still result in just one variable:

        rule "Complex univariate rule"
        when
            $accumulateResult: Collection() from accumulate(
                ...
            )
            $a: Object() from $accumulateResult
            exists Something()
        then
            // Do something with the $a variable.
        end

  To create the simplest possible variant, call `UniLeftHandSide(Class, DroolsVariableFactory)`. Further specializations can be introduced by calling builder methods such as `andFilter(Predicate)`. These builder methods will always return a new instance of `AbstractLeftHandSide`, as these are immutable. Some builder methods, such as `andJoin(UniLeftHandSide, BiJoiner)`, will return an instance of `BiLeftHandSide` (`TriLeftHandSide`, ...), as that particular operation will increase the cardinality of the parent constraint stream.

- - ### Field Summary

    Fields
    Modifier and Type | Field | Description
    --- | --- | ---
    `protected DroolsVariableFactory` | `variableFactory` |

  - ### Constructor Summary

    Constructors
    Modifier | Constructor | Description
    --- | --- | ---
    `` | `UniLeftHandSide​(Class<A> aClass, DroolsVariableFactory variableFactory)` |
    `protected` | `UniLeftHandSide​(org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<A> patternVariable, DroolsVariableFactory variableFactory)` |
    `protected` | `UniLeftHandSide​(UniLeftHandSide<A> leftHandSide, org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<A> patternVariable)` |

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `<B> UniLeftHandSide<A>` | `andExists​(Class<B> bClass, BiJoiner<A,​B>[] joiners)` |
    `UniLeftHandSide<A>` | `andFilter​(Predicate<A> predicate)` |
    `<NewA> UniLeftHandSide<NewA>` | `andGroupBy​(Function<A,​NewA> keyMapping)` |
    `<NewA,​NewB> BiLeftHandSide<NewA,​NewB>` | `andGroupBy​(Function<A,​NewA> keyMappingA, Function<A,​NewB> keyMappingB)` |
    `<NewA,​NewB,​NewC> TriLeftHandSide<NewA,​NewB,​NewC>` | `andGroupBy​(Function<A,​NewA> keyMappingA, Function<A,​NewB> keyMappingB, UniConstraintCollector<A,​?,​NewC> collectorC)` |
    `<NewA,​NewB,​NewC,​NewD> QuadLeftHandSide<NewA,​NewB,​NewC,​NewD>` | `andGroupBy​(Function<A,​NewA> keyMappingA, Function<A,​NewB> keyMappingB, UniConstraintCollector<A,​?,​NewC> collectorC, UniConstraintCollector<A,​?,​NewD> collectorD)` |
    `<NewA,​NewB> BiLeftHandSide<NewA,​NewB>` | `andGroupBy​(Function<A,​NewA> keyMappingA, UniConstraintCollector<A,​?,​NewB> collectorB)` |
    `<NewA> UniLeftHandSide<NewA>` | `andGroupBy​(UniConstraintCollector<A,​?,​NewA> collector)` |
    `<B> BiLeftHandSide<A,​B>` | `andJoin​(UniLeftHandSide<B> right, BiJoiner<A,​B> joiner)` |
    `<B> UniLeftHandSide<A>` | `andNotExists​(Class<B> bClass, BiJoiner<A,​B>[] joiners)` |
    `org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A>` | `andTerminate()` |
    `org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A>` | `andTerminate​(Function<A,​BigDecimal> matchWeighter)` |
    `org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A>` | `andTerminate​(ToIntFunction<A> matchWeighter)` |
    `org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A>` | `andTerminate​(ToLongFunction<A> matchWeighter)` |
    `List<org.drools.model.view.ViewItem<?>>` | `get()` |
    `protected static org.drools.model.Index.ConstraintType` | `getConstraintType​(JoinerType type)` |
    `protected org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<A>` | `getPatternVariableA()` |
    `org.drools.model.Variable[]` | `getVariables()` |
    `protected static org.drools.model.view.ViewItem<?>` | `joinViewItemsWithLogicalAnd​(org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<?>... patternVariables)` |

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### variableFactory

          protected final DroolsVariableFactory variableFactory

  - ### Constructor Detail

    - #### UniLeftHandSide

          public UniLeftHandSide​(Class<A> aClass,
                                 DroolsVariableFactory variableFactory)

    - #### UniLeftHandSide

          protected UniLeftHandSide​(UniLeftHandSide<A> leftHandSide,
                                    org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<A> patternVariable)

    - #### UniLeftHandSide

          protected UniLeftHandSide​(org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<A> patternVariable,
                                    DroolsVariableFactory variableFactory)

  - ### Method Detail

    - #### getPatternVariableA

          protected org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<A> getPatternVariableA()

    - #### andFilter

          public UniLeftHandSide<A> andFilter​(Predicate<A> predicate)

    - #### andExists

          public <B> UniLeftHandSide<A> andExists​(Class<B> bClass,
                                                  BiJoiner<A,​B>[] joiners)

    - #### andNotExists

          public <B> UniLeftHandSide<A> andNotExists​(Class<B> bClass,
                                                     BiJoiner<A,​B>[] joiners)

    - #### andJoin

          public <B> BiLeftHandSide<A,​B> andJoin​(UniLeftHandSide<B> right,
                                                       BiJoiner<A,​B> joiner)

    - #### andGroupBy

          public <NewA> UniLeftHandSide<NewA> andGroupBy​(Function<A,​NewA> keyMapping)

    - #### andGroupBy

          public <NewA> UniLeftHandSide<NewA> andGroupBy​(UniConstraintCollector<A,​?,​NewA> collector)

    - #### andGroupBy

          public <NewA,​NewB> BiLeftHandSide<NewA,​NewB> andGroupBy​(Function<A,​NewA> keyMappingA,
                                                                              Function<A,​NewB> keyMappingB)

    - #### andGroupBy

          public <NewA,​NewB> BiLeftHandSide<NewA,​NewB> andGroupBy​(Function<A,​NewA> keyMappingA,
                                                                              UniConstraintCollector<A,​?,​NewB> collectorB)

    - #### andGroupBy

          public <NewA,​NewB,​NewC> TriLeftHandSide<NewA,​NewB,​NewC> andGroupBy​(Function<A,​NewA> keyMappingA,
                                                                                                     Function<A,​NewB> keyMappingB,
                                                                                                     UniConstraintCollector<A,​?,​NewC> collectorC)

    - #### andGroupBy

          public <NewA,​NewB,​NewC,​NewD> QuadLeftHandSide<NewA,​NewB,​NewC,​NewD> andGroupBy​(Function<A,​NewA> keyMappingA,
                                                                                                                            Function<A,​NewB> keyMappingB,
                                                                                                                            UniConstraintCollector<A,​?,​NewC> collectorC,
                                                                                                                            UniConstraintCollector<A,​?,​NewD> collectorD)

    - #### andTerminate

          public org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A> andTerminate()

    - #### andTerminate

          public org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A> andTerminate​(ToIntFunction<A> matchWeighter)

    - #### andTerminate

          public org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A> andTerminate​(ToLongFunction<A> matchWeighter)

    - #### andTerminate

          public org.optaplanner.core.impl.score.stream.drools.common.AbstractUniConstraintConsequence<A> andTerminate​(Function<A,​BigDecimal> matchWeighter)

    - #### get

          public List<org.drools.model.view.ViewItem<?>> get()

    - #### getVariables

          public org.drools.model.Variable[] getVariables()

    - #### getConstraintType

          protected static org.drools.model.Index.ConstraintType getConstraintType​(JoinerType type)

    - #### joinViewItemsWithLogicalAnd

          protected static org.drools.model.view.ViewItem<?> joinViewItemsWithLogicalAnd​(org.optaplanner.core.impl.score.stream.drools.common.PatternVariable<?>... patternVariables)