Java值更新时如何维护arraylist中扫描对象的顺序

Question

我有一个包含病人姓名和紧急级别的类，实现了可比较的：

class Patient implements Comparable<Patient>{
    private String name;
    private int emergencyLvl;

    public Patient(String name, int emergencyLvl)
    {
        this.name = name;
        this.emergencyLvl = emergencyLvl;

    }

    public String getName(){
        return this.name;

    }
    public int getEmergencyLvl(){
        return this.emergencyLvl;

    }
    public  void  setEmergencyLvl(int updateLvl){
        this.emergencyLvl = updateLvl;

    }
    public void setName(String newName){
        this.name = newName;

    }
    public int compareTo(Patient p){

        int compareEmergency = ((Patient) p).getEmergencyLvl();

        return compareEmergency - this.emergencyLvl;

    **//I believe my error comes from here**




        }
}

**假设这是我的输入文件：

3
0 david 30
0 may 60
1 david 30
2

*3=查询数，0=要添加到arraylist中的新患者，1=更新紧急级别（示例30+30=60)。2=按降序和名称打印紧急级别。**

然而，我的程序成功地扫描并向arraylist中添加了新的病人，但每当需要更新紧急级别时，序列都是错误的。

例如,在david紧急级别更新之前,序列是（david 60,david 30）,但是在david紧急级别更新之后,由于david首先到达,因此正确的序列应该是（david 60,May60）。

不幸的是，我没有正确更新序列。下面是我的主要程序：

UpdateEmergencyLVL：

void UpdateEmergencyLvl(String patientName, int incEmergencyLvl) {

        for(Patient p: a1){
            if(p.getName().equals(patientName)){
                int newEmergencyLvl = p.getEmergencyLvl() +
                incEmergencyLvl;
                p.setEmergencyLvl(newEmergencyLvl);

                }

            }

            Collections.sort(a1);

    }

Answer 1

首先,您需要为类Patient添加一个新属性,您的新public Patient应该如下所示：

public Patient(String name, int emergencyLvl, int patIndx)
        {
            this.name = name;
            this.emergencyLvl = emergencyLvl;
            this.patIndx = patIndx;

        }

完成此操作后,为索引创建一个getter；在您的阅读方法中，您可以在这个索引中添加一个int。对于compare方法，由于到达索引比共享相同的emergencyLvl更重要，所以我会做如下操作：

public int compareTo(Patient p){

        int compareEmergency = ((Patient) p).getEmergencyLvl();

        int aux= compareEmergency - this.emergencyLvl;

        int compareIndex= ((Patient) p).getIndex();
        if(compareIndex>this.patIndx) aux=compareIndex-this.patIndx;
        return aux;    



        }

使用的扫描仪：

 void run() throws Exception {


    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    PrintWriter pr = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
    int numCMD = Integer.parseInt(br.readLine()); // note that numCMD is >= N
    int index=0;//starting index at 0
    while (numCMD-- > 0) {
      StringTokenizer st = new StringTokenizer(br.readLine());
      index++;
      int command = Integer.parseInt(st.nextToken());
      switch (command) {
        case 0: ArriveAtHospital(st.nextToken(), Integer.parseInt(st.nextToken())); 
               // you will need a index setter for this, assuming this is the moment when you add the patient to the patient list:
               ArriveAtHospìtalOrder(index);//as I cant see how the method ArriveAtHospital works, I showed you a possible method that takes the index.
               break;
        case 1: UpdateEmergencyLvl(st.nextToken(), Integer.parseInt(st.nextToken())); break;

        case 3: pr.println(Query()); break;
      }


    }
    pr.close();

这是一种可能的方法，ArriveAtHospitalIndex只是为了说明，因为我不知道您如何将参数传递给ArriveAtHospital方法，这只是为了让您知道应该在什么时候传递索引。你对台词有一点评论。