I know there many similar questions and I have received big help by reading answers to those questions, however I am not able to see how is my client facing this problem. And there is only one client who is facing this problem.
I have a List, and I am sorting that list using Comparator interface. Does any of you see problem with the following code?
private static class BiologySamplesComparator implements Comparator<BiologySample>, Serializable {
@Override
public int compare(BiologySample left, BiologySample right) {
if (left == right || (left != null && right != null && left.getSampleDateTime() == right.getSampleDateTime())) {
return 0;
}
if (left == null || left.getSampleDateTime() == null) {
return 1;
}
if (right == null || right.getSampleDateTime() == null) {
return -1;
}
return right.getSampleDateTime().compareTo(left.getSampleDateTime());
}
}
And this how I am calling this function
Collections.sort(biologySamples, new BiologySamplesComparator());
I know that the main problem in this kind of scenario is Transitivity. However I couldn't figure what is violating that rule.
This how getSampleDateTime() is returning date Fri Apr 09 17:00:00 PDT 2021
Update This is how I was able to fix my problem. I hope this helps, I was stuck for so long on this problem.
private static class BiologySamplesComparator implements Comparator<BiologySample>, Serializable {
@Override
public int compare(BiologySample left, BiologySample right) {
if (left == null) {
if (right == null) {
return 0;
} else {
return 1;
}
} else if (right == null) {
return -1;
} else if (left == right) {
return 0;
}
if (left.getSampleDateTime() == null) {
if (right.getSampleDateTime() == null) {
return 0;
} else {
return 1;
}
} else if (right.getSampleDateTime() == null) {
return -1;
} else if (left.getSampleDateTime() == right.getSampleDateTime()) {
return 0;
}
return right.getSampleDateTime().compareTo(left.getSampleDateTime());
}
}
I was missing some conditional for some cases and this is how I was able to solve my problem.
private static class BiologySamplesComparator implements Comparator<BiologySample>, Serializable {
@Override
public int compare(BiologySample left, BiologySample right) {
if (left == null) {
if (right == null) {
return 0;
} else {
return 1;
}
} else if (right == null) {
return -1;
} else if (left == right) {
return 0;
}
if (left.getSampleDateTime() == null) {
if (right.getSampleDateTime() == null) {
return 0;
} else {
return 1;
}
} else if (right.getSampleDateTime() == null) {
return -1;
} else if (left.getSampleDateTime() == right.getSampleDateTime()) {
return 0;
}
return right.getSampleDateTime().compareTo(left.getSampleDateTime());
}
}
courtesy of Why does my compare methd throw IllegalArgumentException sometimes?