argos/dmp-backend/web/src/main/java/eu/eudat/logic/utilities/helpers/ListHelper.java

15 lines
437 B
Java

package eu.eudat.logic.utilities.helpers;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import java.util.function.Predicate;
public class ListHelper {
public static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) {
Map<Object, Boolean> seen = new ConcurrentHashMap<>();
return t -> seen.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
}
}