Package org.apache.jackrabbit.oak.commons.collections

Class SetUtils

java.lang.Object
org.apache.jackrabbit.oak.commons.collections.SetUtils
public class SetUtils extends Object
Utility methods for Set conversions.

  • Method Details

    • toSet

      @NotNull public static <T> @NotNull Set<T> toSet(@NotNull @NotNull Iterable<? extends T> iterable)
      Convert an iterable to a set. The returning set is mutable and supports all optional operations.
      Type Parameters:
      T - the type of the elements
      Parameters:
      iterable - the iterable to convert
      Returns:
      the set

    • toSet

      @NotNull public static <T> @NotNull Set<T> toSet(@NotNull @NotNull Iterator<T> iterator)
      Convert an iterator to a set. The returning set is mutable and supports all optional operations.
      Type Parameters:
      T - the type of the elements
      Parameters:
      iterator - the iterator to convert
      Returns:
      the set

    • toSet

      @SafeVarargs @NotNull public static <T> @NotNull Set<T> toSet(@NotNull @NotNull T... elements)
      Convert a vararg list of items to a set. The returning set is mutable and supports all optional operations.
      Type Parameters:
      T - the type of the elements
      Parameters:
      elements - elements to convert
      Returns:
      the set

    • newHashSet

      @NotNull public static <K> @NotNull Set<K> newHashSet(int capacity)
      Creates a new, empty HashSet with expected capacity.

      The returned set is large enough to add expected no. of elements without resizing.

      Parameters:
      capacity - the expected number of elements
      Throws:
      IllegalArgumentException - if capacity is negative
      See Also:

    • newIdentityHashSet

      @NotNull public static <E> @NotNull Set<E> newIdentityHashSet()
      Creates a new, empty IdentityHashSet with default size.

    • toLinkedSet

      @NotNull public static <T> @NotNull Set<T> toLinkedSet(@NotNull @NotNull Iterable<? extends T> iterable)
      Convert an iterable to a LinkedHashSet. The returning set is mutable and supports all optional operations.
      Type Parameters:
      T - the type of the elements
      Parameters:
      iterable - the iterable to convert
      Returns:
      the linkedHashSet

    • toLinkedSet

      @SafeVarargs @NotNull public static <T> @NotNull Set<T> toLinkedSet(@NotNull @NotNull T... elements)
      Convert a vararg list of items to a set. The returning set is mutable and supports all optional operations.
      Type Parameters:
      T - the type of the elements
      Parameters:
      elements - elements to convert
      Returns:
      the set

    • newLinkedHashSet

      @NotNull public static <K> @NotNull Set<K> newLinkedHashSet(int capacity)
      Creates a new, empty LinkedHashSet with expected capacity.

      The returned set is large enough to add expected no. of elements without resizing.

      Parameters:
      capacity - the expected number of elements
      Throws:
      IllegalArgumentException - if capacity is negative
      See Also:

    • toTreeSet

      @NotNull public static <T extends Comparable> @NotNull TreeSet<T> toTreeSet(@NotNull @NotNull Iterable<? extends T> iterable)
      Convert an iterable to a TreeSet. The returning set is mutable and supports all optional operations.
      Type Parameters:
      T - the type of the elements
      Parameters:
      iterable - the iterable to convert
      Returns:
      the treeSet
      Throws:
      ClassCastException - if the specified object cannot be compared with the elements currently in this set
      NullPointerException - if the specified element is null and this set uses natural ordering, or its comparator does not permit null elements

    • newConcurrentHashSet

      @NotNull public static <K> @NotNull Set<K> newConcurrentHashSet()
      Creates a new, empty Set which is backed by ConcurrentHashMap to allow concurrent access. Returning Set doesn't allow null keys and values.
      Returns:
      a new, empty Set which is backed by ConcurrentHashMap.
      See Also:

    • newConcurrentHashSet

      @NotNull public static <K> @NotNull Set<K> newConcurrentHashSet(@NotNull @NotNull Iterable<? extends K> elements)
      Creates a new Set with given values which is backed by ConcurrentHashMap to allow concurrent access. Returning Set doesn't allow null keys and values.
      Returns:
      a new, empty Set which is backed by ConcurrentHashMap.
      Throws:
      NullPointerException - if any element of the iterable is null
      See Also:

    • union

      @NotNull public static <T> @NotNull Set<T> union(@NotNull @NotNull Set<T> s1, @NotNull @NotNull Set<T> s2)
      Returns a new set containing the union of the two specified sets. The union of two sets is a set containing all the elements of both sets.
      Type Parameters:
      T - the type of elements in the sets
      Parameters:
      s1 - the first set, must not be null
      s2 - the second set, must not be null
      Returns:
      a new set containing the union of the two specified sets
      Throws:
      NullPointerException - if either of the sets is null

    • intersection

      @NotNull public static <T> @NotNull Set<T> intersection(@NotNull @NotNull Set<T> s1, @NotNull @NotNull Set<T> s2)
      Returns a new set containing the intersection of the two specified sets. The intersection of two sets is a set containing only the elements that are present in both sets.
      Type Parameters:
      T - the type of elements in the sets
      Parameters:
      s1 - the first set, must not be null
      s2 - the second set, must not be null
      Returns:
      a new set containing the intersection of the two specified sets
      Throws:
      NullPointerException - if either of the sets is null

    • symmetricDifference

      public static <T> Set<T> symmetricDifference(Set<T> s1, Set<T> s2)
      Returns a new set containing the symmetric difference of the two specified sets. The symmetric difference of two sets is a set containing elements that are in either of the sets, but not in their intersection.
      Type Parameters:
      T - the type of elements in the sets
      Parameters:
      s1 - the first set, must not be null
      s2 - the second set, must not be null
      Returns:
      a new set containing the symmetric difference of the two specified sets
      Throws:
      NullPointerException - if either of the sets is null

    • difference

      public static <T> Set<T> difference(Set<T> s1, Set<T> s2)
      Returns a new set containing the difference of the two specified sets. The difference of two sets is a set containing elements that are in the first set but not in the second set.
      Type Parameters:
      T - the type of elements in the sets
      Parameters:
      s1 - the first set, must not be null
      s2 - the second set, must not be null
      Returns:
      a new set containing the difference of the two specified sets
      Throws:
      NullPointerException - if either of the sets is null