* Lists#transform}. If only an {@code Iterable} is available, use {@link Iterables#transform}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link java.util.stream.Stream#map Stream.map}.
   */
  public static <F extends @Nullable Object, T extends @Nullable Object> Collection<T> transform(
      Collection<F> fromCollection, Function<? super F, T> function) {

   * <p>If the input {@code Iterable} is known to be a {@code List} or other {@code Collection},
   * consider {@link Lists#transform} and {@link Collections2#transform}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link Stream#map}
   */
  public static <F extends @Nullable Object, T extends @Nullable Object> Iterable<T> transform(
      final Iterable<F> fromIterable, final Function<? super F, ? extends T> function) {
    checkNotNull(fromIterable);

package com.google.common.reflect;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.Iterables.transform;
import static java.util.Objects.requireNonNull;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Joiner;
import com.google.common.base.Objects;

      Iterator<Entry<E>> entryIterator) {
    return new TransformedIterator<Entry<E>, E>(entryIterator) {
      @Override
      @ParametricNullness
      E transform(Entry<E> entry) {
        return entry.getElement();
      }
    };
  }

  abstract static class ElementSet<E extends @Nullable Object> extends Sets.ImprovedAbstractSet<E> {

    List<Integer> listIteratorOnlyList = new ListIterationOnlyList<>(randomAccessList);
    List<String> transform = Lists.transform(listIteratorOnlyList, SOME_FUNCTION);
    assertTrue(
        Iterables.elementsEqual(transform, Lists.transform(randomAccessList, SOME_FUNCTION)));
  }

  private static class ListIterationOnlyList<E> extends ForwardingList<E> {

   *
   * @throws NullPointerException if the function returns {@code null}
   * @since 12.0
   */
  public abstract <V> Optional<V> transform(Function<? super T, V> function);

  /**
   * Returns {@code true} if {@code object} is an {@code Optional} instance, and either the

      // Must be manually synchronized.
      return new TransformedIterator<Map.Entry<K, Collection<V>>, Map.Entry<K, Collection<V>>>(
          super.iterator()) {
        @Override
        Map.Entry<K, Collection<V>> transform(final Map.Entry<K, Collection<V>> entry) {
          return new ForwardingMapEntry<K, Collection<V>>() {
            @Override
            protected Map.Entry<K, Collection<V>> delegate() {
              return entry;

 * submitting a task to a {@link ListeningExecutorService}, and deriving a {@code Future} from an
 * existing one, typically using methods like {@link Futures#transform(ListenableFuture,
 * com.google.common.base.Function, java.util.concurrent.Executor) Futures.transform} and {@link
 * Futures#catching(ListenableFuture, Class, com.google.common.base.Function,
 * java.util.concurrent.Executor) Futures.catching}.
 *

   * Lists#transform}. If only an {@code Iterable} is available, use {@link Iterables#transform}.
   *
   * <p><b>{@code Stream} equivalent:</b> {@link java.util.stream.Stream#map Stream.map}.
   */
  public static <F extends @Nullable Object, T extends @Nullable Object> Collection<T> transform(
      Collection<F> fromCollection, Function<? super F, T> function) {

   *       tasks -- even tasks that are not themselves {@code directExecutor} tasks.
   *   <li>If many such tasks are chained together (such as with {@code
   *       future.transform(...).transform(...).transform(...)....}), they may overflow the stack.
   *       (In simple cases, callers can avoid this by registering all tasks with the same {@link