optaplanner-core/src/main/java/org/optaplanner/core/impl/domain/variable/anchor/AnchorVariableDemand.java
@Override
    public AnchorVariableSupply createExternalizedSupply(InnerScoreDirector scoreDirector) {
        SingletonInverseVariableSupply inverseVariableSupply = scoreDirector.getSupplyManager()
                .demand(new SingletonInverseVariableDemand(sourceVariableDescriptor));
        return new ExternalizedAnchorVariableSupply(sourceVariableDescriptor, inverseVariableSupply);
    }
@Override
    public AnchorVariableSupply createExternalizedSupply(InnerScoreDirector scoreDirector) {
        SingletonInverseVariableSupply inverseVariableSupply = scoreDirector.getSupplyManager()
                .demand(new SingletonInverseVariableDemand(sourceVariableDescriptor));
        return new ExternalizedAnchorVariableSupply(sourceVariableDescriptor, inverseVariableSupply);
    }
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