groovy.util
Class GroovyCollections

java.lang.Object
  groovy.util.GroovyCollections

public class GroovyCollections
extends Object

A Collections utility class

Author:

Paul King, Jim White

Constructor Summary

GroovyCollections()

Method Summary

static List	combinations(Collection collections) Finds all combinations of items from the given collections.
static List	combinations(Object[] collections) Finds all combinations of items from the given collections.
static <T> T	max(Collection<T> items) Selects the maximum value found in a collection
static <T> T	max(T[] items) Selects the maximum value found in an array of items, so min([2, 4, 6] as Object[]) == 6.
static <T> T	min(Collection<T> items) Selects the minimum value found in a collection 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(Collection items) Sums all the items from a collection of items.
static Object	sum(Object[] items) Sums all the items from an array of items.
static List	transpose(List lists) Transposes the given lists.
static List	transpose(Object[] lists) Transposes an array of lists.

Methods inherited from class java.lang.Object

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

Constructor Detail

GroovyCollections

public GroovyCollections()

Method Detail

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:

combinations(Collection)

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(Collection collections)

Finds all combinations of items from the given 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']].

Parameters:

collections - the given collections

Returns:

a List of the combinations found

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(List)

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(Collection<T> items)

Selects the minimum value found in a collection of items.

Parameters:

items - a Collection

Returns:

the minimum value

max

public static <T> T max(T[] items)

Selects the maximum value found in an array of items, so min([2, 4, 6] as Object[]) == 6.

Parameters:

items - an array of items

Returns:

the maximum value

max

public static <T> T max(Collection<T> items)

Selects the maximum value found in a collection

Parameters:

items - a Collection

Returns:

the maximum value

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(Collection items)

Sums all the items from a collection of items.

Parameters:

items - a collection of items

Returns:

the sum of the items