Package groovy.util

Class GroovyCollections

java.lang.Object
groovy.util.GroovyCollections
public class GroovyCollections extends Object
A Collections utility class

  • Constructor Summary

    Constructors
    Constructor
    Description
    GroovyCollections()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static List
    combinations(Iterable collections)
    Finds all combinations of items from the given Iterable aggregate of collections.
    static List
    combinations(Object[] collections)
    Finds all combinations of items from the given collections.
    static <T> List<List<T>>
    inits(Iterable<T> collections)
     
    static <T> T
    max(Iterable<T> items)
    Selects the maximum value found in an Iterable.
    static <T> T
    max(T[] items)
    Selects the maximum value found in an array of items, so max([2, 4, 6] as Object[]) == 6.
    static <T> T
    min(Iterable<T> items)
    Selects the minimum value found in an Iterable of items.
    static <T> T
    min(T[] items)
    Selects the minimum value found in an array of items, so min([2, 4, 6] as Object[]) == 2.
    static <T> Set<List<T>>
    subsequences(List<T> items)
    Finds all non-null subsequences of a list.
    static Object
    sum(Iterable<?> items)
    Sums all the given items.
    static Object
    sum(Object[] items)
    Sums all the items from an array of items.
    static <T> List<List<T>>
    tails(Iterable<T> collections)
     
    static List
    transpose(Object[] lists)
    Transposes an array of lists.
    static List
    transpose(List lists)
    Transposes the given lists.
    static <T> List<T>
    union(Closure condition, Iterable<T>... iterables)
    Returns an ordered set of all the unique items found in the provided argument iterables using the provided closure to compare items.
    static <T> List<T>
    union(Iterable<T>... iterables)
    Returns an ordered set of all the unique items found in the provided argument iterables.
    static <T> List<T>
    union(Comparator<T> comparator, Iterable<T>... iterables)
    Returns an ordered set of all the unique items found in the provided argument iterables using the provided comparator to compare items.
    static <T> List<T>
    union(List<Iterable<T>> iterables)
    Returns an ordered set of all the unique items found in the provided argument iterables.
    static <T> List<T>
    union(List<Iterable<T>> iterables, Closure condition)
    Returns an ordered set of all the unique items found in the provided argument iterables using the provided closure to compare items.
    static <T> List<T>
    union(List<Iterable<T>> iterables, Comparator<T> comparator)
    Returns an ordered set of all the unique items found in the provided argument iterables using the provided comparator to compare items.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • GroovyCollections

      public GroovyCollections()

  • Method Details

    • combinations

      public static List combinations(Object[] collections)
      Finds all combinations of items from the given collections.
      Parameters:
      collections - the given collections
      Returns:
      a List of the combinations found
      See Also:

    • subsequences

      public static <T> Set<List<T>> subsequences(List<T> items)
      Finds all non-null subsequences of a list. E.g. subsequences([1, 2, 3]) would be: [[1, 2, 3], [1, 3], [2, 3], [1, 2], [1], [2], [3]]
      Parameters:
      items - the List of items
      Returns:
      the subsequences from items

    • combinations

      public static List combinations(Iterable collections)
      Finds all combinations of items from the given Iterable aggregate of collections. So, combinations([[true, false], [true, false]]) is [[true, true], [false, true], [true, false], [false, false]] and combinations([['a', 'b'],[1, 2, 3]]) is [['a', 1], ['b', 1], ['a', 2], ['b', 2], ['a', 3], ['b', 3]]. If a non-collection item is given, it is treated as a singleton collection, i.e. combinations([[1, 2], 'x']) is [[1, 'x'], [2, 'x']]. If an empty collection is found within the given collections, the result will be an empty list.
      Parameters:
      collections - the Iterable of given collections
      Returns:
      a List of the combinations found
      Since:
      2.2.0

    • inits

      public static <T> List<List<T>> inits(Iterable<T> collections)

    • tails

      public static <T> List<List<T>> tails(Iterable<T> collections)

    • transpose

      public static List transpose(Object[] lists)
      Transposes an array of lists.
      Parameters:
      lists - the given lists
      Returns:
      a List of the transposed lists
      See Also:

    • transpose

      public static List transpose(List lists)
      Transposes the given lists. So, transpose([['a', 'b'], [1, 2]]) is [['a', 1], ['b', 2]] and transpose([['a', 'b', 'c']]) is [['a'], ['b'], ['c']].
      Parameters:
      lists - the given lists
      Returns:
      a List of the transposed lists

    • min

      public static <T> T min(T[] items)
      Selects the minimum value found in an array of items, so min([2, 4, 6] as Object[]) == 2.
      Parameters:
      items - an array of items
      Returns:
      the minimum value

    • min

      public static <T> T min(Iterable<T> items)
      Selects the minimum value found in an Iterable of items.
      Parameters:
      items - an Iterable
      Returns:
      the minimum value
      Since:
      2.2.0

    • max

      public static <T> T max(T[] items)
      Selects the maximum value found in an array of items, so max([2, 4, 6] as Object[]) == 6.
      Parameters:
      items - an array of items
      Returns:
      the maximum value

    • max

      public static <T> T max(Iterable<T> items)
      Selects the maximum value found in an Iterable.
      Parameters:
      items - a Collection
      Returns:
      the maximum value
      Since:
      2.2.0

    • sum

      public static Object sum(Object[] items)
      Sums all the items from an array of items.
      Parameters:
      items - an array of items
      Returns:
      the sum of the items

    • sum

      public static Object sum(Iterable<?> items)
      Sums all the given items.
      Parameters:
      items - an Iterable of items
      Returns:
      the sum of the item
      Since:
      2.2.0

    • union

      public static <T> List<T> union(Iterable<T>... iterables)
      Returns an ordered set of all the unique items found in the provided argument iterables. 
       assert GroovyCollections.union([1, 2], [2, 3], [1, 4]) == [1, 2, 3, 4]
      Parameters:
      iterables - the sources of items
      Returns:
      the ordered list of unique values found
      Since:
      4.0.0

    • union

      public static <T> List<T> union(List<Iterable<T>> iterables)
      Returns an ordered set of all the unique items found in the provided argument iterables. 
       assert GroovyCollections.union([[1, 2], [2, 3], [1, 4]]) == [1, 2, 3, 4]
      Parameters:
      iterables - the list of source items
      Returns:
      the ordered list of unique values found
      Since:
      4.0.0

    • union

      public static <T> List<T> union(Comparator<T> comparator, Iterable<T>... iterables)
      Returns an ordered set of all the unique items found in the provided argument iterables using the provided comparator to compare items. 
       assert GroovyCollections.union(n -> n.abs(), [1, 2, 5], [-3, -4, -5], [4, 6]) == [1, 2, 5, -3, -4, 6]
 assert GroovyCollections.union(n -> n.trunc(), [1.1, 2.2], [2.5, 3.3], [3.9, 4.1]) == [1.1, 2.2, 3.3, 4.1]
 assert GroovyCollections.union(w -> w.toUpperCase(), ['a', 'A'], ['B', 'a', 'c', 'b']) == ['a', 'B', 'c']
      Parameters:
      comparator - a Comparator
      iterables - the sources of items
      Returns:
      the ordered list of unique values found
      Since:
      4.0.0

    • union

      public static <T> List<T> union(List<Iterable<T>> iterables, Comparator<T> comparator)
      Returns an ordered set of all the unique items found in the provided argument iterables using the provided comparator to compare items. 
       assert GroovyCollections.union([[1, 2, 5], [-3, -4, -5], [4, 6]], n -> n.abs()) == [1, 2, 5, -3, -4, 6]
 assert GroovyCollections.union([[1.1, 2.2], [2.5, 3.3], [3.9, 4.1]], n -> n.trunc()) == [1.1, 2.2, 3.3, 4.1]
 assert GroovyCollections.union([['a', 'A'], ['B', 'a', 'c', 'b']], w -> w.toUpperCase()) == ['a', 'B', 'c']
      Parameters:
      iterables - the list of source items
      comparator - a Comparator
      Returns:
      the ordered list of unique values found
      Since:
      4.0.0

    • union

      public static <T> List<T> union(Closure condition, Iterable<T>... iterables)
      Returns an ordered set of all the unique items found in the provided argument iterables using the provided closure to compare items. 
       def abs = { n -> n.abs() }
 assert GroovyCollections.union(abs, [1, 2, 5], [-3, -4, -5], [4, 6]) == [1, 2, 5, -3, -4, 6]
      Parameters:
      condition - a Closure used to determine unique items
      iterables - the sources of items
      Returns:
      the ordered list of unique values found
      Since:
      4.0.0

    • union

      public static <T> List<T> union(List<Iterable<T>> iterables, Closure condition)
      Returns an ordered set of all the unique items found in the provided argument iterables using the provided closure to compare items. 
       assert GroovyCollections.union([[1, 2, 5], [-3, -4, -5], [4, 6]]){ n -> n.abs() } == [1, 2, 5, -3, -4, 6]
      Parameters:
      iterables - the list of source items
      condition - a Closure used to determine unique items
      Returns:
      the ordered list of unique values found
      Since:
      4.0.0