java - Spring Boot (STS) 中无法识别 ConstraintCollectors

Question

我正在尝试使用 Optaplanner 约束提供程序，它工作正常，直到我想使用 count() ConstraintCollector。

我尝试在 groupBy 子句中使用它，但收到错误:The method count() is undefined for the type hamxConstraintProvider我的假设是这应该“有效”？或者我应该编写自己的计数方法？我在示例中找不到这种情况，但似乎也无法修复它。我是否忽略了导入？

import org.optaplanner.core.api.score.stream.Constraint;
import org.optaplanner.core.api.score.stream.ConstraintFactory;
import org.optaplanner.core.api.score.stream.ConstraintProvider;
import org.optaplanner.core.api.score.stream.uni.UniConstraintCollector;
import org.optaplanner.core.api.score.stream.bi.BiConstraintCollector;
import org.optaplanner.core.api.score.stream.ConstraintCollectors.*;
import org.optaplanner.core.api.score.stream.Joiners.*;

...

public class hamxConstraintProvider implements ConstraintProvider{


    @Override
    public Constraint[] defineConstraints(ConstraintFactory constraintFactory) {
        return new Constraint[] {
                skillUnavailable(constraintFactory),
                balancedJobs(constraintFactory)
        };
    }


...

    private Constraint balancedJobs(ConstraintFactory factory) {

        return factory.from(Job.class)
                .groupBy(Job::getEmployee,count())
                .penalize("unbalancedEmployeeUsage", HardSoftScore.ONE_SOFT,count);
    }

Answer 1

而不是

import org.optaplanner.core.api.score.stream.ConstraintCollectors.*;
import org.optaplanner.core.api.score.stream.Joiners.*;

使用静态导入:

import static org.optaplanner.core.api.score.stream.ConstraintCollectors.*;
import static org.optaplanner.core.api.score.stream.Joiners.*;

前者导入类，后者导入静态方法。