org.forgerock.openam.utils

Class CollectionUtils

java.lang.Object

org.forgerock.openam.utils.CollectionUtils

public final class CollectionUtils
extends Object

A simple utility class to simplify interactions with collections.

Method Summary

Modifier and Type	Method and Description
static boolean	anyHaveEntries(Object... containers) See if any of the containers have entries and if so return true.
static Set	asCaseInsensitiveHashSet(Object... values) Collects the passed in objects into a case insensitive hash set.
static <T> List<T>	asList(T... values) Collects the passed in objects into a List.
static <T> LinkedHashSet<T>	asOrderedSet(T... values) Collects the passed in objects to a LinkedHashSet.
static <T> Set<T>	asSet(T... values) Collects the passed in objects into an unordered Set.
static boolean	compareCaseInsensitiveMapOfSetOfStrings(Map<String,Set<String>> valA, Map<String,Set<String>> valB) Compares two map collections containing sets of strings in a case insensitive manner.
static int	createHashForCaseInsensitiveMapOfSetOfStrings(Map<String,Set<String>> map) Creates a hash code for a map of set of strings in a case insensitive manner.
static <T> boolean	genericCompare(T valA, T valB) Compares any two arbitrary objects - including collections, for equality.
static <T> T	getFirstItem(Collection<T> collection) Retrieves the first item from a collection.
static <T> T	getFirstItem(Collection<T> collection, T defaultValue) Retrieves the first item from a collections.
static <K,V> Map<V,K>	invertMap(Map<K,V> map) Creates a new Map which contains the entries of the provided map but with keys and values exchanged.
static boolean	isEmpty(Collection<?> collection) Determines whether the collections is null or empty.
static boolean	isEmpty(Map<?,?> map) Given a map determines whether it contains some values.
static boolean	isNotEmpty(Collection<?> collection) Given a collection determines whether it contains some values.
static boolean	isNotEmpty(Map<?,?> map) Given a map determines whether it contains some values.
static <T> List<T>	newList(Collection<T> collection) Returns an ArrayList of the items in the provided collection, or null if the set is null.
static Set<String>	removeBlankEntries(Set<String> originalSet) From the original Set of Strings, remove any entries that are blank.
static <K,V extends Comparable<? super V>> Map<K,V>	sortMapByValue(Map<K,V> map) Sort the given Map by comparing it's values.
static Map<String,Set<String>>	toAvPairMap(Set<String> names, String value) Creates a Hash Map, of names mapped to the provided value.
static <I,M,E extends Exception> List<M>	transformList(Collection<I> values, org.forgerock.util.Function<I,M,E> mapper) Maps the non-null values from one type to another type using a non-null mapper function.
static <K,I,M,E extends Exception> Map<K,M>	transformMap(Map<K,I> map, org.forgerock.util.Function<I,M,E> mapper) Maps the values of a non-null map from one type to another type using a non-null mapper function.
static <I,M,E extends Exception> Set<M>	transformSet(Collection<I> values, org.forgerock.util.Function<I,M,E> mapper) Maps the non-null values from one type to another type using a non-null mapper function.

Methods inherited from class java.lang.Object

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

Method Detail

removeBlankEntries

public static Set<String> removeBlankEntries(Set<String> originalSet)

From the original Set of Strings, remove any entries that are blank.

Parameters:

originalSet - The Set of Strings to check

Returns:

A copy of the original Set less any blank String entries.

asList

public static <T> List<T> asList(T... values)

Collects the passed in objects into a List.

Type Parameters:

T - The type of the passed in objects.

Parameters:

values - An unbounded amount of objects that needs to be collected to a List.

Returns:

Either an empty list (if there was no value passed in), or a List that holds all the values passed in.

asCaseInsensitiveHashSet

public static Set asCaseInsensitiveHashSet(Object... values)

Collects the passed in objects into a case insensitive hash set. Unfortunately case insensitive hash sets are not generic.

Parameters:

values - An unbounded amount of objects that needs to be converted to a case insensitive hash set.

Returns:

Either an empty set (if there was no value passed in), or a Set that holds all the values passed in.

asSet

public static <T> Set<T> asSet(T... values)

Collects the passed in objects into an unordered Set.

Type Parameters:

T - The type of the passed in objects.

Parameters:

values - An unbounded amount of objects that needs to be converted to a Set.

Returns:

Either an empty set (if there was no value passed in), or a Set that holds all the values passed in.

asOrderedSet

public static <T> LinkedHashSet<T> asOrderedSet(T... values)

Collects the passed in objects to a LinkedHashSet.

Type Parameters:

T - The type of the passed in objects.

Parameters:

values - An unbounded amount of objects that needs to be converted to a Set.

Returns:

Either an empty set (if there was no value passed in), or a Set that holds all the values in the exact same order as passed in.

invertMap

public static <K,V> Map<V,K> invertMap(Map<K,V> map)

Creates a new Map which contains the entries of the provided map but with keys and values exchanged.

Type Parameters:

K - the type of keys in the provided map; the type of the values in the returned map.

V - the type of values in the provided map; the type of the keys in the returned map.

Parameters:

map - the non-null original map.

Returns:

a new map with inverted key-value mapping.

transformMap

public static <K,I,M,E extends Exception> Map<K,M> transformMap(Map<K,I> map,
                                                                org.forgerock.util.Function<I,M,E> mapper)
                                                         throws E extends Exception

Maps the values of a non-null map from one type to another type using a non-null mapper function.

Type Parameters:

K - the type of key

I - the type of the initial value

M - the type of the mapped value

E - the type of exception that the function may throw

Parameters:

map - the non-null original map

mapper - the non-null mapping function

Returns:

a new map with the mapped values

Throws:

E - should an exception occur during the mapping process

E extends Exception

transformList

public static <I,M,E extends Exception> List<M> transformList(Collection<I> values,
                                                              org.forgerock.util.Function<I,M,E> mapper)
                                                       throws E extends Exception

Maps the non-null values from one type to another type using a non-null mapper function.

Type Parameters:

I - the type of the initial value

M - the type of the mapped value

E - the type of exception that the function may throw

Parameters:

values - the non-null original values

mapper - the non-null mapping function

Returns:

a new list with the mapped values

Throws:

E - should an exception occur during the mapping process

E extends Exception

transformSet

public static <I,M,E extends Exception> Set<M> transformSet(Collection<I> values,
                                                            org.forgerock.util.Function<I,M,E> mapper)
                                                     throws E extends Exception

Maps the non-null values from one type to another type using a non-null mapper function.

Type Parameters:

I - the type of the initial value

M - the type of the mapped value

E - the type of exception that the function may throw

Parameters:

values - the non-null original values

mapper - the non-null mapping function

Returns:

a new list with the mapped values

Throws:

E - should an exception occur during the mapping process

E extends Exception

getFirstItem

public static <T> T getFirstItem(Collection<T> collection)

Retrieves the first item from a collection.

Type Parameters:

T - The type of the collection.

Parameters:

collection - The collection.

Returns:

The first instance of the collection else null if not present.

getFirstItem

public static <T> T getFirstItem(Collection<T> collection,
                                 T defaultValue)

Retrieves the first item from a collections.

Type Parameters:

T - the type of the collection

Parameters:

collection - the collection

defaultValue - the default value should not initial value exist

Returns:

the first instance of the collection else null if not present

genericCompare

public static <T> boolean genericCompare(T valA,
                                         T valB)

Compares any two arbitrary objects - including collections, for equality. It also handles either of the objects being null without issue.

Type Parameters:

T - The type of the objects being compared.

Parameters:

valA - The first object to be compared.

valB - The second object to tbe compared.

Returns:

true if the parameter values are the same, false if different.

compareCaseInsensitiveMapOfSetOfStrings

public static boolean compareCaseInsensitiveMapOfSetOfStrings(Map<String,Set<String>> valA,
                                                              Map<String,Set<String>> valB)

Compares two map collections containing sets of strings in a case insensitive manner.

Parameters:

valA - - the first map of set of strings to be compared.

valB - - the second map of set of strings to be compared.

Returns:

true if the parameter values are the same, false if different.

createHashForCaseInsensitiveMapOfSetOfStrings

public static int createHashForCaseInsensitiveMapOfSetOfStrings(Map<String,Set<String>> map)

Creates a hash code for a map of set of strings in a case insensitive manner. This is needed so that if a case insensitive equality is applied to the map, the hash is generated in a similar and consisent manner.

Parameters:

map - - the map of set of strings for which the hash code is to be generated.

Returns:

the generated hash code.

isNotEmpty

public static boolean isNotEmpty(Collection<?> collection)

Given a collection determines whether it contains some values.

Parameters:

collection - collection in question

Returns:

whether the collection contains any values

isEmpty

public static boolean isEmpty(Collection<?> collection)

Determines whether the collections is null or empty.

Parameters:

collection - the collection

Returns:

whether the collection is null or empty

toAvPairMap

public static Map<String,Set<String>> toAvPairMap(Set<String> names,
                                                  String value)

Creates a Hash Map, of names mapped to the provided value. If there is no value, an empty map is returned.

Parameters:

names - The set of names to be associated with the provided value.

value - The value to be mapped to each of the provided names.

Returns:

The map of name / value pairs, otherwise an Empty Map if no value is provided or an empty hashmap if no names are specified.

isEmpty

public static boolean isEmpty(Map<?,?> map)

Given a map determines whether it contains some values.

Parameters:

map - map in question

Returns:

whether the map contains any values

isNotEmpty

public static boolean isNotEmpty(Map<?,?> map)

Given a map determines whether it contains some values.

Parameters:

map - map in question

Returns:

whether the map contains any values

anyHaveEntries

public static boolean anyHaveEntries(Object... containers)

See if any of the containers have entries and if so return true. Any argument which is not a Collection or a Map is ignored.

Parameters:

containers - a varied list of maps and collections

Returns:

true if any one of the maps and/or collections have entries

sortMapByValue

public static <K,V extends Comparable<? super V>> Map<K,V> sortMapByValue(Map<K,V> map)

Sort the given Map by comparing it's values.

Type Parameters:

K - The key type.

V - The value type.

Parameters:

map - The map to sort.

Returns:

The given map sorted and presented in a LinkedHashMap to guarantee iteration order.

newList

public static <T> List<T> newList(Collection<T> collection)

Returns an ArrayList of the items in the provided collection, or null if the set is null.

Type Parameters:

T - The type of value.

Parameters:

collection - The collection.

Returns:

The list, or null if the collection was null.