Getting a redundant null check error in the following code block. Can someone help me refactor it:
private Date pickRecent(Date d1, Date d2, Date d3, Date crd) {
logger.debug("d1: " + d1 + " d2: " + d2 + " d3: " + d3 + " crd: " + crd);
// all null
if (d1 == null && d2 == null && d3 == null) return crd;
logger.debug("through all");
// two null
if (d1 == null && d2 == null) return d3;
if (d1 == null && d3 == null) return d2;
if (d2 == null && d3 == null) return d1;
logger.debug("through two");
// one null
if (d1 == null) if (d2.after(d3)) return d2; else return d3;
if (d2 == null) if (d1.after(d3)) return d1; else return d3;
if (d3 == null) if (d1.after(d2)) return d1; else return d2;
logger.debug("through one");
// none null
if (d1.after(d2) && d1.after(d3)) return d1;
if (d2.after(d1) && d2.after(d3)) return d2;
if (d3.after(d1) && d3.after(d2)) return d3;
if (d1.equals(d2) && d1.equals(d3)) return d1;
logger.debug("through none");
return null;
}
Here's one possible solution...
import java.util.Arrays;
import java.util.Comparator;
import java.util.Date;
public class RecentDate
{
public static void main(String[] args)
{
System.out.println(pickRecent(new Date(1, 1, 1), new Date(2, 2, 2), new Date(3, 3, 3), new Date(4, 4, 4)));
System.out.println(pickRecent(null, null, null));
}
private static Date pickRecent(Date...dates)
{
return Arrays.stream(dates).filter(d -> d != null).max(Comparator.naturalOrder()).orElse(null);
}
}
Output:
Wed May 04 00:00:00 CST 1904
null
public static Date pickRecent(Date one, Date two, Date three, Date crd) {
Set<Date> unique = new TreeSet<>(Comparator.reverseOrder());
if (one != null)
unique.add(one);
if (two != null)
unique.add(two);
if (three != null)
unique.add(three);
return unique.size() == 1 ? unique.iterator().next() : crd;
}
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