Class CollectionUtils


  • public class CollectionUtils
    extends java.lang.Object

    Utility methods for working with Collection types

    .
    Since:
    1.0
    • Constructor Summary

      Constructors 
      Constructor Description
      CollectionUtils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static <T> java.util.Optional<java.lang.Iterable<T>> convertCollection​(java.lang.Class<? extends java.lang.Iterable<T>> iterableType, java.util.Collection<T> collection)
      Attempts to convert a collection to the given iterabable type
      static <T> java.lang.Iterable<T> enumerationToIterable​(java.util.Enumeration<T> enumeration)
      Convert an Enumeration to a Iterable.
      static <T> java.util.Set<T> enumerationToSet​(java.util.Enumeration<T> enumeration)
      Convert an Enumeration to a Set.
      static boolean isEmpty​(java.util.Collection collection)
      Null safe empty check.
      static boolean isEmpty​(java.util.Map map)
      Null safe empty check.
      static boolean isIterableOrMap​(java.lang.Class<?> type)
      Is the given type an iterable or map type.
      static boolean isNotEmpty​(java.util.Collection collection)
      Null safe not empty check.
      static boolean isNotEmpty​(java.util.Map map)
      Null safe not empty check.
      static <T> java.util.List<T> iterableToList​(java.lang.Iterable<T> iterable)
      Converts an Iterable to a List.
      static <T> java.util.Set<T> iterableToSet​(java.lang.Iterable<T> iterable)
      Converts an Iterable to a Set.
      static <T> java.util.Set<T> iteratorToSet​(java.util.Iterator<T> iterator)
      Convert an Iterator to a Set.
      static <T> T last​(java.util.Collection<T> collection)
      Returns the last element of a collection.
      static java.util.Map mapOf​(java.lang.Object... values)
      Create a LinkedHashMap from an array of values.
      static <T> java.util.Set<T> setOf​(T... objects)
      Creates a set of the given objects.
      static java.lang.String toString​(java.lang.Iterable<?> iterable)
      Produce a string representation of the given iterable.
      static java.lang.String toString​(java.lang.String delimiter, java.lang.Iterable<?> iterable)
      Produce a string representation of the given iterable.
      static <T> java.util.List<T> unmodifiableList​(java.util.List<T> list)
      Null safe version of Collections.unmodifiableList(List).
      • 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

      • isIterableOrMap

        public static boolean isIterableOrMap​(java.lang.Class<?> type)
        Is the given type an iterable or map type.
        Parameters:
        type - The type
        Returns:
        True if it is iterable or map
        Since:
        2.0.0
      • isEmpty

        public static boolean isEmpty​(@Nullable
                                      java.util.Map map)
        Null safe empty check.
        Parameters:
        map - The map
        Returns:
        True if it is empty or null
      • isNotEmpty

        public static boolean isNotEmpty​(@Nullable
                                         java.util.Map map)
        Null safe not empty check.
        Parameters:
        map - The map
        Returns:
        True if it is not null and not empty
      • isEmpty

        public static boolean isEmpty​(@Nullable
                                      java.util.Collection collection)
        Null safe empty check.
        Parameters:
        collection - The collection
        Returns:
        True if it is empty or null
      • isNotEmpty

        public static boolean isNotEmpty​(@Nullable
                                         java.util.Collection collection)
        Null safe not empty check.
        Parameters:
        collection - The collection
        Returns:
        True if it is not null and not empty
      • convertCollection

        public static <T> java.util.Optional<java.lang.Iterable<T>> convertCollection​(java.lang.Class<? extends java.lang.Iterable<T>> iterableType,
                                                                                      java.util.Collection<T> collection)

        Attempts to convert a collection to the given iterabable type

        .
        Type Parameters:
        T - The collection generic type
        Parameters:
        iterableType - The iterable type
        collection - The collection
        Returns:
        An Optional of the converted type
      • mapOf

        public static java.util.Map mapOf​(java.lang.Object... values)
        Create a LinkedHashMap from an array of values.
        Parameters:
        values - The values
        Returns:
        The created map
      • iteratorToSet

        public static <T> java.util.Set<T> iteratorToSet​(java.util.Iterator<T> iterator)
        Convert an Iterator to a Set.
        Type Parameters:
        T - The type
        Parameters:
        iterator - The iterator
        Returns:
        The set
      • enumerationToSet

        public static <T> java.util.Set<T> enumerationToSet​(java.util.Enumeration<T> enumeration)
        Convert an Enumeration to a Set.
        Type Parameters:
        T - The type
        Parameters:
        enumeration - The iterator
        Returns:
        The set
      • enumerationToIterable

        @NonNull
        public static <T> java.lang.Iterable<T> enumerationToIterable​(@Nullable
                                                                      java.util.Enumeration<T> enumeration)
        Convert an Enumeration to a Iterable.
        Type Parameters:
        T - The type
        Parameters:
        enumeration - The iterator
        Returns:
        The set
      • setOf

        public static <T> java.util.Set<T> setOf​(T... objects)
        Creates a set of the given objects.
        Type Parameters:
        T - The type
        Parameters:
        objects - The objects
        Returns:
        The set
      • toString

        public static java.lang.String toString​(java.lang.Iterable<?> iterable)
        Produce a string representation of the given iterable.
        Parameters:
        iterable - The iterable
        Returns:
        The string representation
      • toString

        public static java.lang.String toString​(java.lang.String delimiter,
                                                java.lang.Iterable<?> iterable)
        Produce a string representation of the given iterable.
        Parameters:
        delimiter - The delimiter
        iterable - The iterable
        Returns:
        The string representation
      • iterableToList

        public static <T> java.util.List<T> iterableToList​(java.lang.Iterable<T> iterable)
        Converts an Iterable to a List.
        Type Parameters:
        T - The generic type
        Parameters:
        iterable - The iterable
        Returns:
        The list
      • iterableToSet

        public static <T> java.util.Set<T> iterableToSet​(java.lang.Iterable<T> iterable)
        Converts an Iterable to a Set.
        Type Parameters:
        T - The generic type
        Parameters:
        iterable - The iterable
        Returns:
        The set
      • unmodifiableList

        @NonNull
        public static <T> java.util.List<T> unmodifiableList​(@Nullable
                                                             java.util.List<T> list)
        Null safe version of Collections.unmodifiableList(List).
        Type Parameters:
        T - The generic type
        Parameters:
        list - The list
        Returns:
        A non-null unmodifiable list
      • last

        @Nullable
        public static <T> T last​(@NonNull
                                 java.util.Collection<T> collection)
        Returns the last element of a collection.
        Type Parameters:
        T - The generic type
        Parameters:
        collection - The collection
        Returns:
        The last element of a collection or null