Class CollectionUtil


  • public class CollectionUtil
    extends Object
    • Constructor Detail

      • CollectionUtil

        public CollectionUtil()
    • Method Detail

      • combinations

        public static List combinations​(List original,
                                        int maxCombinationSize)
        Returns a List of Lists: all combinations of the elements of the given List.
        Parameters:
        maxCombinationSize - combinations larger than this value are discarded
      • inverse

        public static Map inverse​(Map map)
      • combinations

        public static List combinations​(List original,
                                        int maxCombinationSize,
                                        Object mandatoryItem)
        Returns a List of Lists: all combinations of the elements of the given List.
        Parameters:
        maxCombinationSize - combinations larger than this value are discarded
        mandatoryItem - an item that all returned combinations must contain, or null to leave unspecified
      • combinations

        public static List combinations​(List original)
        Returns a List of Lists: all combinations of the elements of the given List.
      • removeKeys

        public static void removeKeys​(Collection keys,
                                      Map map)
      • keysAndCorrespondingValues

        public static List[] keysAndCorrespondingValues​(Map map)
        The nth key corresponds to the nth value
      • randomElement

        public static Object randomElement​(List list)
      • reverseSortedSet

        public static SortedSet reverseSortedSet​(int[] ints)
      • reverse

        public static List reverse​(List list)
      • stretch

        public static Collection stretch​(Collection source,
                                         Collection destination,
                                         int destinationSize)
        Data is evenly discarded or duplicated to attain the new size
      • setIfNull

        public static void setIfNull​(int i,
                                     List list,
                                     String value)
      • resize

        public static void resize​(List list,
                                  int newSize)
      • containsReference

        public static boolean containsReference​(Object[] objects,
                                                Object o)
      • indexOf

        public static int indexOf​(Object o,
                                  Object[] objects)
      • removeDuplicates

        public static Collection removeDuplicates​(Collection original)
        Brute force, for when HashSet and TreeSet won't work (e.g. #hashCode implementation isn't appropriate). The original Collection is not modified.
      • addIfNotNull

        public static void addIfNotNull​(Object item,
                                        Collection collection)
      • filterByClass

        public static Collection filterByClass​(Collection collection,
                                               Class c)
        Modifies and returns the collection.
      • createMap

        public static Map createMap​(Object[] alternatingKeysAndValues)
      • createMap

        public static Map createMap​(Class mapClass,
                                    Object[] alternatingKeysAndValues)