SortedSet unique key problem

Question

i want a SortedSet of patients. each has a unique id and a current heartRate .
i want to sort them by heartRate .
i am getting duplicate entries when the id is constant but the heartRate changes.
please consider this:
SortedSet<Patient>();
public class Patient {
  public int id;
  public int heartBeat;
public class PatientComparator implements Comparator {
  public int compare(Object obj1, Object obj2) {
    Patient p1 = (Patient) obj1; // <------- this downcast works... downcasts are illegal
    Patient p2 = (Patient) obj2; // yet how else can i write the Comparator? i don't get it.
    if(p1.heartBeat > p2.heartBeat) { return(1); }
    if(p1.heartBeat < p2.heartBeat) { return(-1); }
    return(0);
  public boolean equals(Object obj1, Object obj2) {
    Patient p1 = (Patient) obj1;
    Patient p2 = (Patient) obj2;
    return(p1.id == p2.id);
summary :
each time the same patient id has heartRate change, i get a new entry in the SortedSet .
the related issue, how could you write a Comparator without a downcast?

Answer 1

The equals method must be implemented in Patient class, not in PatientComparatori am still getting multiple entries even with this implementation:
public class Patient extends Object {
  public int id;
  public int heartBeat;
  public boolean equals(Object obj) {
    return(true);  // <---
}further, i am also implementing Comparator this way:
public class PatientComparator implements Comparator<Patient> {
  public boolean equals(Patient p1, Patient p2) {
    return(true); // <---
}and i still get multiple entries.
so, what method() does a Set use to guarantee that there are no duplicate entries?
and what key is used to uniquely identify an object in the Collection ?
when mySet.add((MyObj) myObj); i think the process should be:
(1) if myObj already exists in mySet remove it.
(2) add myObj to mySet .
for me, either step #1 is not happening, or there is something wrong with the keys .
i want to make the key patient.id .