Class CollectionsUtil


  • public class CollectionsUtil
    extends java.lang.Object
    • Constructor Summary

      Constructors 
      Constructor Description
      CollectionsUtil()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      private static <A> java.util.List<A> cast​(java.lang.Class<A> clazz, java.util.Collection<? extends java.lang.Object> objects, CollectionsUtil.CastOption castOption)
      Cast objects to clazz
      static <A> java.util.List<A> castAll​(java.lang.Class<A> clazz, java.util.Collection<? extends java.lang.Object> objects)
      Unchecked cast objects to clazz; CastClassException will occur when object sent in does not match clazz

      Use when all objects are expected to be of type class and exception is desired if not
      static <A> java.util.List<A> castAll​(java.util.Collection<?> objects)
      Cast objects to clazz
      static <A> java.util.List<A> castMatching​(java.lang.Class<A> clazz, java.util.Collection<? extends java.lang.Object> objects)
      Cast objects matching class, ignore rest; no ClassCastException will occur

      Use when objects may contain classes that are not desired
      static java.util.Collection<java.lang.String> fromString​(java.lang.String string, java.lang.String seperator)  
      static <T> java.util.List<T> getAggregate​(T... objects)
      Convert an aggregate list of objects into a List
      static java.util.List<java.lang.Object> getAggregateTree​(java.util.List<java.lang.Object> items, int maxPerList)  
      static <T> boolean isEqual​(java.util.Collection<T> listA, java.util.Collection<T> listB)
      Return true if same objects exist in listA and listB
      private static java.util.List<java.lang.Object> recursiveAggregateTree​(java.util.List<java.lang.Object> items, int maxPerList)  
      static <T> java.util.List<T> setComplement​(java.util.Collection<T> superSet, java.util.Collection<T> subList)
      The resultant set is those elements in superSet which are not in the subSet
      static <T> java.util.List<T> setIntersection​(java.util.Collection<T> listA, java.util.Collection<T> listB)  
      static <T> java.util.Set<T> setUnion​(java.util.Collection<T>... lists)
      Returns the unique union of the given lists
      static java.lang.String toString​(java.lang.String separator, java.lang.Object... objects)  
      static java.lang.String toString​(java.lang.String separator, java.util.Collection c)  
      static java.lang.String toString​(java.util.Collection c, java.lang.String start, java.lang.String separator, java.lang.String end)
      An flexible alternative for converting a Collection to a String.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • CollectionsUtil

        public CollectionsUtil()
    • Method Detail

      • fromString

        public static java.util.Collection<java.lang.String> fromString​(java.lang.String string,
                                                                        java.lang.String seperator)
      • toString

        public static java.lang.String toString​(java.util.Collection c,
                                                java.lang.String start,
                                                java.lang.String separator,
                                                java.lang.String end)
        An flexible alternative for converting a Collection to a String.
        Parameters:
        c - The Collection to convert to a String
        start - The String to place at the beginning of the returned String
        separator - The String to place in between elements of the Collection c.
        end - The String to place at the end of the returned String
        Returns:
        A String which starts with 'start', followed by the elements in the Collection c separated by 'separator', ending with 'end'.
      • toString

        public static java.lang.String toString​(java.lang.String separator,
                                                java.lang.Object... objects)
      • toString

        public static java.lang.String toString​(java.lang.String separator,
                                                java.util.Collection c)
      • setComplement

        public static <T> java.util.List<T> setComplement​(java.util.Collection<T> superSet,
                                                          java.util.Collection<T> subList)
        The resultant set is those elements in superSet which are not in the subSet
      • setIntersection

        public static <T> java.util.List<T> setIntersection​(java.util.Collection<T> listA,
                                                            java.util.Collection<T> listB)
        Returns:
        The intersection of two sets A and B is the set of elements common to A and B
      • setUnion

        @SafeVarargs
        public static <T> java.util.Set<T> setUnion​(java.util.Collection<T>... lists)
        Returns the unique union of the given lists
      • isEqual

        public static <T> boolean isEqual​(java.util.Collection<T> listA,
                                          java.util.Collection<T> listB)
        Return true if same objects exist in listA and listB
      • getAggregate

        @SafeVarargs
        public static <T> java.util.List<T> getAggregate​(T... objects)
        Convert an aggregate list of objects into a List
      • getAggregateTree

        public static java.util.List<java.lang.Object> getAggregateTree​(java.util.List<java.lang.Object> items,
                                                                        int maxPerList)
      • recursiveAggregateTree

        private static java.util.List<java.lang.Object> recursiveAggregateTree​(java.util.List<java.lang.Object> items,
                                                                               int maxPerList)
      • cast

        private static <A> java.util.List<A> cast​(java.lang.Class<A> clazz,
                                                  java.util.Collection<? extends java.lang.Object> objects,
                                                  CollectionsUtil.CastOption castOption)
        Cast objects to clazz
        Parameters:
        castOption - if ALL, cast all and throw exception if cast fails; if MATCHING, only cast those of type clazz
      • castAll

        public static <A> java.util.List<A> castAll​(java.util.Collection<?> objects)
        Cast objects to clazz
      • castAll

        public static <A> java.util.List<A> castAll​(java.lang.Class<A> clazz,
                                                    java.util.Collection<? extends java.lang.Object> objects)
        Unchecked cast objects to clazz; CastClassException will occur when object sent in does not match clazz

        Use when all objects are expected to be of type class and exception is desired if not
      • castMatching

        public static <A> java.util.List<A> castMatching​(java.lang.Class<A> clazz,
                                                         java.util.Collection<? extends java.lang.Object> objects)
        Cast objects matching class, ignore rest; no ClassCastException will occur

        Use when objects may contain classes that are not desired