/**
 * 用于管理一对对象的简单DTO
 */
class Pair<T> {
    public first: T;
    public second: T;

    constructor(first: T, second: T){
        this.first = first;
        this.second = second;
    }

    public clear(){
        this.first = this.second = null;
    }

    public equals(other: Pair<T>){
        return this.first == other.first && this.second == other.second;
    }
}