Question

我可以使用策略模式来实现以下逻辑：因此，想象学费是根据学生的整体表现来计算的，例如，如果学生的总体平均分数超过70，他的学费将减少70％。等等..如果平均标记是50％折扣50％，在其他情况下没有折扣。因此，有不同的计算折扣的策略因平均分数而异。如何在Java代码中实现它？我想学生班将有计算平均分数的方法，界面TuitionFeeCalculator和三个策略：70persentDiscount，50％折扣和noDiscount实施TuitionFeeCalculator。

Answer 1

假设这只是一个课堂练习，因为你永远不会为简单的事情实施策略模式，但你要找的是：

df[df.column1 > someValue]

Answer 2

有人可以查看此代码并告诉我是否有错误

 public class StrategyDemo
 {

  public static void main(String[] args)
  {
    Student s = new Student();
    TuitionFee fee = new TuitionFee();
    fee.setTuitionFee(5000);
    StudentStatus status = new StudentStatus(s);
    CalculatorSelectorFactory calc = new CalculatorSelectorFactory(status.getStatus());
    TuitionFeeCalculator tfc = calc.getCalculator();
    double newFee = tfc.calculate();



  }
}


public class StudentStatus
{
  private Student student;

  public StudentStatus(Student student){
    this.student = student;
  }
  public List<Module> getAllModules(){
        //query the database and get all modules a particular student is enrolled for
        return modules; //return list of modules
  }
  public int getStatus(){
    int total = 0;
    int count = 0;
    for(Module m: getAllModules()){
        total += m.getMark();
        count++;
    }
    int average = total/count;
    return average;
  }
}
public class TuitionFee{
    private double tuitionFee;

    public void setTuitionFee(double tuitionFee){
        this.tuitionFee = tuitionFee;
    }
    public double getTuitionFee(){
        return tuitionFee;
    }
}
public interface TuitionFeeCalculator{
    public double calculate();
}
public class Discount70 implements TuitionFeeCalculator{
    @Override
    public double calculate(TuitionFee tuitionFee){
        double discount = tuitionFee * 0.7; //70% discount
        return tuitionFee-discount;
    }
}
public class Discount50 implements TuitionFeeCalculator{
    @Override
    public double calculate(TuitionFee tuitionFee){
        double discount = tuitionFee * 0.5; //50% discount
        return tuitionFee-discount;
    }
}
public class NoDiscount implements TuitionFeeCalculator{
    @Override
    public double calculate(TuitionFee tuitionFee){
        return tuitionFee; //no discount
    }
}

public class CalculatorSelectorFactory{
    TuitionFeeCalculator tfc;
    public CalculatorSelectorFactory(int status){
        if(status>=70){
          tfc=new Discount70();
        }
        else if(status>=50){
          tfc = new Discount50();
        }
        else{
          tfc = new NoDiscount();
        }       
    }
    public TuitionFeeCalculator getCalculator(){
        return tfc;
    }
}

战略设计模式用例在大学Intranet系统的开发中的应用

2 个答案: