Class CollectionUtil


  • public class CollectionUtil
    extends java.lang.Object
    helper/convience methods for working with collections.
    Author:
    Joram Barrez
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static <S,​T>
      void
      addCollectionToMapOfSets​(java.util.Map<S,​java.util.Set<T>> map, S key, java.util.Collection<T> values)  
      static <S,​T>
      void
      addToMapOfLists​(java.util.Map<S,​java.util.List<T>> map, S key, T value)  
      static <S,​T>
      void
      addToMapOfSets​(java.util.Map<S,​java.util.Set<T>> map, S key, T value)  
      static <T> java.util.List<T> asArrayList​(T[] values)
      Arrays.asList cannot be reliably used for SQL parameters on MyBatis < 3.3.0
      static <T> java.util.Set<T> asHashSet​(T... elements)  
      static <T> java.util.List<T> collectInList​(java.util.Iterator<T> iterator)  
      static boolean isEmpty​(java.util.Collection<?> collection)  
      static <T> java.util.List<java.util.List<T>> partition​(java.util.List<T> list, int partitionSize)
      Chops a list into non-view sublists of length partitionSize.
      static java.util.Map<java.lang.String,​java.lang.Object> singletonMap​(java.lang.String key, java.lang.Object value)
      Helper method that creates a singleton map.
      • Methods inherited from class java.lang.Object

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

      • singletonMap

        public static java.util.Map<java.lang.String,​java.lang.Object> singletonMap​(java.lang.String key,
                                                                                          java.lang.Object value)
        Helper method that creates a singleton map. Alternative for Collections.singletonMap(), since that method returns a generic typed map depending on the input type, but we often need a map.
      • asArrayList

        public static <T> java.util.List<T> asArrayList​(T[] values)
        Arrays.asList cannot be reliably used for SQL parameters on MyBatis < 3.3.0
      • asHashSet

        public static <T> java.util.Set<T> asHashSet​(T... elements)
      • addToMapOfLists

        public static <S,​T> void addToMapOfLists​(java.util.Map<S,​java.util.List<T>> map,
                                                       S key,
                                                       T value)
      • addToMapOfSets

        public static <S,​T> void addToMapOfSets​(java.util.Map<S,​java.util.Set<T>> map,
                                                      S key,
                                                      T value)
      • addCollectionToMapOfSets

        public static <S,​T> void addCollectionToMapOfSets​(java.util.Map<S,​java.util.Set<T>> map,
                                                                S key,
                                                                java.util.Collection<T> values)
      • partition

        public static <T> java.util.List<java.util.List<T>> partition​(java.util.List<T> list,
                                                                      int partitionSize)
        Chops a list into non-view sublists of length partitionSize. Note: the argument list may be included in the result.
      • collectInList

        public static <T> java.util.List<T> collectInList​(java.util.Iterator<T> iterator)
      • isEmpty

        public static boolean isEmpty​(java.util.Collection<?> collection)