Could anyone tell me the logic behind this piece of code?
public int compareTo(Holder o) {
if(o == null) return -1;
return this.value.compareTo(o.value);
}
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user1167596
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2Well, how is the return value of `Comparable.compareTo` documented? How does that tally with what's going on here? Which specific part do you not understand? – Jon Skeet May 12 '16 at 09:10
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1You just need to look here https://docs.oracle.com/javase/8/docs/api/java/lang/Comparable.html – Alessandro Dal Gobbo May 12 '16 at 09:10
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3You can get more details here http://stackoverflow.com/questions/10017381/compareto-method-java – AnupamBhusari May 12 '16 at 09:13
1 Answers
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It compares this against another object o.
If o is null, then this is considered smaller than o (indicated by return value -1).
Otherwise the fields value of this and o are compared and the result is returned as comparison result (-1 = smaller, 1 = greater, 0 = equal).
The rationale is to have a proper ordering of elements, e.g. to sort a list.
Stefan Winkler
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1In plain words, it orders `null` after everything else (with everything else in its natural order according to its `.value`). – Amadan May 12 '16 at 09:12