CollectionSetter.java

import javax.annotation.Nonnull;
import java.util.Collection;
/**
 * Utility class for setters of collections in objects.
 *
 * <pre>
 * {@code
 * private Set<String> items = new HashSet<>();
 * public void setItems(Collection<String> items) {
 *    CollectionSetter.refill(this.items, items);
 * }
 * }
 * </pre>
 */
public final class CollectionSetter {
    /**
     * Clears the collection and puts values from the new collection into it
     * @param collection Collection (not null)
     * @param newCollection Collection
     */
    public static <T> void refill(@Nonnull Collection<? super T> collection, Collection<? extends T> newCollection) {
        collection.clear();
        if (newCollection != null) {
            collection.addAll(newCollection);
        }
    }
}