Translating beans

Collectors.java

package siscom.model.pg;

import static java.util.stream.Collectors.collectingAndThen;
import static java.util.stream.Collectors.toList;

import java.util.stream.Collector;

public final class Collectors {

	private Collectors() {
		throw new UnsupportedOperationException();
	}

	public static final <T, A, R> Collector<T, A, R> toSerializableList() {
		return (Collector<T, A, R>) collectingAndThen(toList(), e -> new SerializableArrayList<>(e));
	}
}

Translator.java

package siscom.model.transform;

import static java.util.stream.Collectors.toList;

import java.util.List;
import java.util.Optional;
import java.util.function.Function;

import siscom.model.pg.Collectors;
import siscom.model.pg.PaginatedList;
import siscom.model.pg.SerializableList;
import siscom.model.pg.SerializablePaginatedList;

public final class Translator {

	private Translator() {
		throw new UnsupportedOperationException();
	}

	public static <F, T> T translate(final F from, final Function<F, T> translator) {
		return Optional.ofNullable(from).map(translator).orElse(null);
	}

	public static <F, T> SerializablePaginatedList<T> translate(final SerializablePaginatedList<F> source,
			final Function<F, T> translator) {
		final List<T> out = source.stream().map(translator).collect(toList());
		return PaginatedList.newList(source.getTotalSize(), source.getCurrentPage(), source.getTotalPages(), source.getFirstResult(), out);
	}

	public static <F, T> SerializableList<T> translate(final List<F> source, final Function<F, T> translator) {
		if (source == null) {
			return SerializableList.empty();
		}

		if (source instanceof SerializablePaginatedList) {
			return translate((SerializablePaginatedList<F>) source, translator);
		}

		return source.stream().map(translator).collect(Collectors.toSerializableList());
	}
}