1 /* 2 * Copyright (c) 2016 Mockito contributors 3 * This program is made available under the terms of the MIT License. 4 */ 5 package org.mockito.internal.util.collections; 6 7 import java.util.Enumeration; 8 import java.util.Iterator; 9 import java.util.LinkedList; 10 import java.util.List; 11 12 /** 13 * Utilities for Iterables 14 */ 15 public class Iterables { 16 17 /** 18 * Converts enumeration into iterable 19 */ toIterable(Enumeration<T> in)20 public static <T> Iterable<T> toIterable(Enumeration<T> in) { 21 List<T> out = new LinkedList<T>(); 22 while(in.hasMoreElements()) { 23 out.add(in.nextElement()); 24 } 25 return out; 26 } 27 28 /** 29 * Returns first element of provided iterable or fails fast when iterable is empty. 30 * 31 * @param iterable non-empty iterable 32 * @return first element of supplied iterable 33 * @throws IllegalArgumentException when supplied iterable is empty 34 */ firstOf(Iterable<T> iterable)35 public static <T> T firstOf(Iterable<T> iterable) { 36 Iterator<T> iterator = iterable.iterator(); 37 if (!iterator.hasNext()) { 38 throw new IllegalArgumentException("Cannot provide 1st element from empty iterable: " + iterable); 39 } 40 return iterator.next(); 41 } 42 } 43