Java8 - get by index but something similar to 'getOrDefault' for Map?

Question

Is there a cleaner way to check whether a value is present at a particular index like list.getOrDefault(index, "defaultValue"). Or even do a default operation when the particular index is out of range of the list.

The normal way to do this is to check for size of the list before attempting this operation.

Answer 1

The default List interface does not have this functionality. There is Iterables.get in Guava:

Iterables.get(iterable, position, defaultValue);

Returns the element at the specified position in iterable or defaultValue if iterable contains fewer than position + 1 elements.

Throws IndexOutOfBoundsException if position is negative.

If this is functionality you intend to use a lot and can't afford to depend on third-party libraries, you could write your own static method (here inspired by the Guava Lists class):

public class Lists {

  public static <E> E getOrDefault(int index, E defaultValue, List<E> list) {
    if (index < 0) {
      throw new IllegalArgumentException("index is less than 0: " + index);
    }
    return index <= list.size() - 1 ? list.get(index) : defaultValue;
  }

}