java如何将方法与比较类型的附加功能进行比较？

Question

如果对象属于参数中提供的特定类型，我想使用类型为的附加参数创建一个比较器，以便为属性添加更多优先级。比如说,

new Comparator<Person>(){ 
    @override
    public int compare(Person p1, Person p2, Person.Type type, float weight)
    {
        float score1 = p1.getScore();
        float score2 = p2.getScore();
        if(p1.getType==type)
            score1 = weight * score1;
        if(p2.getType==type)
            score2 = weight * score2;
        return Double.compare(score1,score2);
    }
}

我想找到一种方法，在对象是特定类型时实现这种行为

Answer 1

由于额外的参数，您的compare方法不再实现Comparator

要提供这些值，请在构造函数中将这些值传递给这个Comparator类

public class PersonComparator implements Comparator<Person>
{
    private Person.Type type;
    private float weight;
    public PersonComparator(Person.Type type, float weight) {
       this.type = type;
       this.weight = weight;
    }
}

然后，您可以使用适当的签名实现compare方法，方法体将使用您需要的值

public int compare(Person person1, Person person2)

Answer 2

您不能修改正在运行的接口

public int compare(T, T);

所以，如果你想增加重量和类型，我建议你添加一些东西，比如比较器的字段

public class  YourComparator implements Comparator<Person> { 
    private Person.Type type;
    private float weight;

    public YourComparator(Person.Type type, float weight) {
       this.type = type;
       this.weight = weight;
    }

    @override
    public int compare(Person p1, Person p2) {
        float score1 = p1.getScore();
        float score2 = p2.getScore();
        if(p1.getType==this.type)
            score1 = this.weight * score1;
        if(p2.getType==this.type)
            score2 = this.weight * score2;
        return Double.compare(score1,score2);
    }
}

如果要使用匿名类实现，可以在容器方法（或容器对象中的字段）中将这些属性设置为final，并直接引用它们

final Person.Type type = Person.Type.SUPER_HEROE;
final float weight = 0.38f;

Comparator<Person> comparator = new Comparator<Person>() { 
    @Override
    public int compare(Person p1, Person p2) {
        float score1 = p1.getScore();
        float score2 = p2.getScore();
        if(p1.getType==type)
            score1 = weight * score1;
        if(p2.getType==type)
            score2 = weight * score2;
        return Double.compare(score1,score2);
    }
};