Class CollectionUtils

java.lang.Object
io.micronaut.core.util.CollectionUtils

public class CollectionUtils extends Object

Utility methods for working with Collection types

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Since:
1.0
Author:
Graeme Rocher
  • Constructor Details

    • CollectionUtils

      public CollectionUtils()
  • Method Details

    • isIterableOrMap

      public static boolean isIterableOrMap(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 Map map)
      Null safe empty check.
      Parameters:
      map - The map
      Returns:
      True if it is empty or null
    • isNotEmpty

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

      public static boolean isNotEmpty(@Nullable 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> Optional<Iterable<T>> convertCollection(Class<? extends Iterable<T>> iterableType, 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 Map mapOf(Object... values)
      Create a LinkedHashMap from an array of values.
      Parameters:
      values - The values
      Returns:
      The created map
    • iteratorToSet

      public static <T> Set<T> iteratorToSet(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> Set<T> enumerationToSet(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> Iterable<T> enumerationToIterable(@Nullable 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> 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 String toString(Iterable<?> iterable)
      Produce a string representation of the given iterable.
      Parameters:
      iterable - The iterable
      Returns:
      The string representation
    • toString

      public static String toString(String delimiter, 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> List<T> iterableToList(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> Set<T> iterableToSet(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> List<T> unmodifiableList(@Nullable List<T> 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 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