Package liquibase.util

Class CollectionUtil

java.lang.Object

liquibase.util.CollectionUtil

public class CollectionUtil
extends Object

Constructor Summary

Constructors

Constructor	Description
CollectionUtil()

Method Summary

Modifier and Type	Method	Description
static <T> List<T>	createIfNull(List<T> currentValue)	Returns passed currentValue if it is not null and creates a new ArrayList if it is null.
static <T,E> Map<T,E>	createIfNull(Map<T,E> currentValue)	Returns a new empty map if the passed map is null.
static <T> Set<T>	createIfNull(Set<T> currentValue)	Returns a new empty set if the passed set is null.
static <T> T[]	createIfNull(T[] arguments)	Returns a new empty array if the passed array is null.
static String	findKeyInMapIgnoreCase(String key, Map<String,Object> map)	Find the actual key in a map, by searching the keys in the map and checking them ignoring case.
static Map<String,Object>	flatten(Map<String,Object> map)	Converts a set of nested maps (like from yaml/json) into a flat map with dot-separated properties
static <T> List<Map<String,T>>	permutations(Map<String,List<T>> parameterValues)
static <T> Set<Set<T>>	powerSet(Collection<T> originalSet)

Methods inherited from class java.lang.Object

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

Constructor Detail

CollectionUtil

public CollectionUtil()

Method Detail

powerSet

public static <T> Set<Set<T>> powerSet(Collection<T> originalSet)

permutations

public static <T> List<Map<String,T>> permutations(Map<String,List<T>> parameterValues)

createIfNull

public static <T> List<T> createIfNull(List<T> currentValue)

Returns passed currentValue if it is not null and creates a new ArrayList if it is null.

Example: values = createIfNull(values)

createIfNull

public static <T> T[] createIfNull(T[] arguments)

Returns a new empty array if the passed array is null.

createIfNull

public static <T> Set<T> createIfNull(Set<T> currentValue)

Returns a new empty set if the passed set is null.

createIfNull

public static <T,E> Map<T,E> createIfNull(Map<T,E> currentValue)

Returns a new empty map if the passed map is null.

flatten

public static Map<String,Object> flatten(Map<String,Object> map)

Converts a set of nested maps (like from yaml/json) into a flat map with dot-separated properties

findKeyInMapIgnoreCase

public static String findKeyInMapIgnoreCase(String key,
                                            Map<String,Object> map)

Find the actual key in a map, by searching the keys in the map and checking them ignoring case.

Parameters:

key - the key to search for, in any case

map - the map in which to search

Returns:

the properly cased key, if found, or null if not found