Package org.drasyl.util

Class SetUtil

java.lang.Object
org.drasyl.util.SetUtil
public final class SetUtil extends Object
Utility class for operations on Sets.

  • Method Details

    • merge

      public static <E> Set<E> merge(Set<E> a, Set<E> b)
      Returns a set containing all elements from set a and set b. If there are duplicates in both sets, the elements from the set a are favored.
      Type Parameters:
      E - the Set's element type
      Parameters:
      a - set a
      b - set b
      Returns:
      a Set containing the specified elements

    • merge

      @SafeVarargs public static <E> Set<E> merge(Set<E> a, E... b)
      Returns a set containing all elements from a and the element b. b is ignored if an equal element is already contained in the set a.
      Type Parameters:
      E - the Set's element type
      Parameters:
      a - set a
      b - set b
      Returns:
      a Set containing the specified elements

    • difference

      public static <E> Set<E> difference(Set<E> a, Collection<E> b)
      Returns a set containing all elements from set a that are not in set b.
      Type Parameters:
      E - the Set's element type
      Parameters:
      a - set a
      b - set b
      Returns:
      a Set containing the specified elements

    • difference

      @SafeVarargs public static <E> Set<E> difference(Set<E> a, E... b)
      Returns a set containing all elements from set a that are not b.
      Type Parameters:
      E - the Set's element type
      Parameters:
      a - set a
      b - set b
      Returns:
      a Set containing the specified elements

    • nthElement

      public static <E> E nthElement(Set<E> set, int n)
      Returns the n-th element from set set. Throws a IndexOutOfBoundsException if n is negative or greater than the set's cardinality.
      Type Parameters:
      E - the Set's element type
      Parameters:
      set - a set
      n - specifies the element to be taken
      Returns:
      n-th element from set set
      Throws:
      IndexOutOfBoundsException - if n is negative or greater than the set's cardinality

    • firstElement

      public static <E> E firstElement(Set<E> set)
      Returns the first element from set set. Returns null if set is empty.
      Type Parameters:
      E - the Set's element type
      Parameters:
      set - a set
      Returns:
      first element from set set

    • firstElements

      public static <E> Set<E> firstElements(Set<E> set, int n)
      Returns the first n elements from set set.
      Type Parameters:
      E - the Set's element type
      Parameters:
      set - a set
      n - elements to return
      Returns:
      first n elements from set set
      Throws:
      IllegalArgumentException - if n is negative

    • cartesianProduct

      public static <A, B> Set<Pair<A,B>> cartesianProduct(Set<A> a, Set<B> b)
      Returns the cartesian product of the two sets a and b. This is the set of all ordered Pairs (x,y) where x is in a and y is in b.
      Type Parameters:
      A - the type of the elements in set a
      B - the type of the elements in set b
      Parameters:
      a - first set for the cartesian product
      b - second set for the cartesian product
      Returns:
      the cartesian product of the two sets a and b