Consider this class.
public class DynamicField implements Comparable<DynamicField> {
String title;
int position;
int order;
@Override
public int compareTo(DynamicField o) {
if(position < o.position)
return -1;
if(position > o.position)
return 1;
if(order < o.order)
return -1;
if(order > o.order)
return 1;
return title.compareTo(o.title);
}
}
Is the compareTo method correct if I want to sort by title, position and then order?
No,Try this code Updated
public class DynamicField implements Comparable<DynamicField> {
String title;
int position;
int order;
@Override
public int compareTo(DynamicField o) {
int result = title.compareTo(o.title);
if(result != 0) {}
else if(position != o.position)
result = position-o.position;
else if(order != o.order)
result = order- o.order;
return result;
}
}
No, you're making comparisons in an incorrect order. Rearranging comparisons order would make it work:
@Override
public int compareTo(DynamicField o) {
int c = title.compareTo(o.title);
if (c != 0)
return c;
if(position < o.position)
return -1;
if(position > o.position)
return 1;
if(order < o.order)
return -1;
if(order > o.order)
return 1;
return 0;
}
This is actually the same as @org.life.java's answer. You might find this one more palatable, though.
@Override
public int compareTo() {
int result = title.compareTo(o.title);
if (result == 0)
result = position - o.position;
if (result == 0)
result = order - o.order;
return result;
}
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