code: public static <T> int firstIndexOf(T[] items, T item) {
  		for (int i = 0; i != items.length; ++i) {
  			T ith = items[i];
  			if (ith == item || (ith != null && ith.equals(item))) {
  				return i;
  			}
  		}
  		return -1;
  	}
docs: Determine the first index of a given item in an array of items, or return
  -1 otherwise. Items are compared using the method
  <code>Object.equals()</code>. The <code>items</code> array may contain
  <code>null</code> values; likewise, <code>item</code> may be
  <code>null</code> and will match against other <code>null</code> values.
  
  @param items
  @param item
  @return