Class CollectionUtil


  • public class CollectionUtil
    extends Object
    Small utility methods for dealing with collection classes.
    • Field Detail

      • OBJECT_TOSTRING_COMPARATOR

        public static final Comparator<Object> OBJECT_TOSTRING_COMPARATOR
        Simple case-insensitive lexical comparator of objects using their Object.toString() value.
    • Constructor Detail

      • CollectionUtil

        public CollectionUtil()
    • Method Detail

      • makeList

        public static <T> List<T> makeList​(T... list)
      • makeSet

        public static <T> Set<T> makeSet​(T... list)
      • join

        public static String join​(Collection<?> items,
                                  String inBetween)
        Construct a string by toString()ing each item in the collection with inBetween between each item.
      • getSoleElement

        public static <T> T getSoleElement​(Collection<T> items)
      • partition

        @Deprecated
        public static <K,​V> Map<K,​Collection<V>> partition​(Collection<V> collection,
                                                                       CollectionUtil.Partitioner<V,​K> p)
        Deprecated.
        use java8 .stream().collect(Collectors.groupingBy(()-> function)) instead
        Partitions a collection into groups based on a characteristics of that group. Partitions are embodied in a map, whose keys are the value of that characteristic, and the values are the partition of elements whose characteristic evaluate to that key.
      • partition

        public static <K,​V> Map<K,​Collection<V>> partition​(Collection<V> collection,
                                                                       Function<? super V,​? extends K> keyer)
        Partitions a collection into groups based on a characteristics of that group. Partitions are embodied in a map, whose keys are the value of that characteristic, and the values are the partition of elements whose characteristic evaluate to that key.