Reusable method to transform Iterable to T[]?

Question

I\'m trying to write a generic method to return the contents of an Iterable in array form.

Here is what I have:

public class IterableHelp
{
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Answer 1

There's a method Iterables.toArray in Google Guava.

Looking at the source, it's defined as:

  /**
   * Copies an iterable's elements into an array.
   *
   * @param iterable the iterable to copy
   * @param type the type of the elements
   * @return a newly-allocated array into which all the elements of the iterable
   *     have been copied
   */
  public static  T[] toArray(Iterable iterable, Class type) {
    Collection collection = toCollection(iterable);
    T[] array = ObjectArrays.newArray(type, collection.size());
    return collection.toArray(array);
  }

Where ObjectArrays.newArray eventually delegates to a method that looks like:

  /**
   * Returns a new array of the given length with the specified component type.
   *
   * @param type the component type
   * @param length the length of the new array
   */
  @SuppressWarnings("unchecked")
  static  T[] newArray(Class type, int length) {
    return (T[]) Array.newInstance(type, length);
  }

So it looks like there's no way to avoid the @SuppressWarnings entirely, but you can and should at least constrain it to the smallest possible scope.

Or, better yet, just use somebody else's implementation!