Class CollectionUtils


  • public class CollectionUtils
    extends java.lang.Object
    Utility methods for dealing with Collections, including treating null collections as empty.
    • Constructor Summary

      Constructors 
      Constructor Description
      CollectionUtils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static <T> T getFirst​(java.util.Collection<T> collection)
      first/last
      static <T> T getLast​(java.util.List<T> list)  
      static int getLastIndex​(java.util.List<?> list)  
      static <T> boolean isEmpty​(java.util.Collection<T> collection)
      empty
      static boolean isLastIndex​(java.util.List<?> list, int index)  
      static <T> boolean notEmpty​(java.util.Collection<T> collection)  
      static <T> java.util.Collection<T> nullSafe​(java.util.Collection<T> in)  
      static <A,​B>
      boolean
      nullSafeSameSize​(java.util.Collection<A> a, java.util.Collection<B> b)  
      static <T> int nullSafeSize​(java.util.Collection<T> collection)
      size
      • Methods inherited from class java.lang.Object

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

      • CollectionUtils

        public CollectionUtils()
    • Method Detail

      • nullSafe

        public static <T> java.util.Collection<T> nullSafe​(java.util.Collection<T> in)
      • nullSafeSize

        public static <T> int nullSafeSize​(java.util.Collection<T> collection)
        size
      • nullSafeSameSize

        public static <A,​B> boolean nullSafeSameSize​(java.util.Collection<A> a,
                                                           java.util.Collection<B> b)
      • isEmpty

        public static <T> boolean isEmpty​(java.util.Collection<T> collection)
        empty
      • notEmpty

        public static <T> boolean notEmpty​(java.util.Collection<T> collection)
      • getFirst

        public static <T> T getFirst​(java.util.Collection<T> collection)
        first/last
      • getLastIndex

        public static int getLastIndex​(java.util.List<?> list)
        Parameters:
        list - any list
        Returns:
        -1 if list is empty, otherwise the max index
      • isLastIndex

        public static boolean isLastIndex​(java.util.List<?> list,
                                          int index)
        Parameters:
        list -
        index - the index in question
        Returns:
        true if it is the last index or if list is empty and -1 is passed for the index param
      • getLast

        public static <T> T getLast​(java.util.List<T> list)