Package org.identityconnectors.common

Class CollectionUtil

java.lang.Object

org.identityconnectors.common.CollectionUtil

public final class CollectionUtil
extends Object

Method Summary

Modifier and Type	Method	Description
static <T> List<T>	asReadOnlyList(List<T> list)	Returns a read-only list.
static <T,K> Map<T,K>	asReadOnlyMap(Map<T,K> map)
static boolean	equals(Object o1, Object o2)	Equality function that properly handles arrays, lists, maps, lists of arrays, and maps of arrays.
static <T> int	forceCompare(Object o1, Object o2)	Forces the compare of two comparable objects and removes any warnings generated by the compiler.
static int	hashCode(Object o)	hashCode function that properly handles arrays, collections, maps, collections of arrays, and maps of arrays.
static <T> Set<T>	intersection(Collection<T> c1, Collection<T> c2)	Returns the intersection of two Collections as an unmodifiable set.
static boolean	isCaseInsensitiveMap(Map<?,?> map)	Returns true if the given map is a case-insensitive map.
static boolean	isCaseInsensitiveSet(Set<?> set)	Returns true if the given set is a case-insensitive set.
static <T> boolean	isEmpty(Collection<T> c)	Determine if Collection is empty or not, protects against null being passed in.
static <T> SortedMap<String,T>	newCaseInsensitiveMap()	Creates a case-insensitive map.
static SortedSet<String>	newCaseInsensitiveSet()	Creates a case-insensitive set.
static <T> List<T>	newList(Collection<? extends T> c)	Create a modifiable list from the Collection provided.
static <T> List<T>	newList(T... arr)	Create a modifiable list from the arguments.
static Map<String,String>	newMap(Properties properties)
static <T,K> Map<T,K>	newMap(T[] k, K[] v)	Builds a map from two arrays.
static <T,K> Map<T,K>	newMap(T k0, K v0)
static <T,K> Map<T,K>	newMap(T k0, K v0, T k1, K v1)
static <T,K> Map<T,K>	newMap(T k0, K v0, T k1, K v1, T k2, K v2)
static <T,K> Map<T,K>	newMap(T k0, K v0, T k1, K v1, T k2, K v2, T k3, K v3)
static <T,K> Map<T,K>	newMap(T k0, K v0, T k1, K v1, T k2, K v2, T k3, K v3, T k4, K v4)
static <T,K> Map<T,K>	newMap(T k0, K v0, T k1, K v1, T k2, K v2, T k3, K v3, T k4, K v4, T k5, K v5)
static <T,K> Map<T,K>	newMapFromLists(List<T> keys, List<K> values)	Converts two List to a map.
static <T> List<T>	newReadOnlyList(Collection<? extends T> c)	Creates an unmodifiable List from a collection.
static <T> List<T>	newReadOnlyList(List<? extends T> list)	Create an unmodifiable List based on the List passed in checks for null and returns an empty list if null is passed in.
static <T> List<T>	newReadOnlyList(T... obj)	Creates an unmodifiable List from a variable number arguments.
static <T,K> Map<T,K>	newReadOnlyMap(Map<T,K> map)
static <T> Map<T,T>	newReadOnlyMap(T[][] kv)
static <T> Set<T>	newReadOnlySet(Collection<T> c)	Creates an unmodifiable set from a Collection.
static <T> Set<T>	newReadOnlySet(T... arr)	Creates an unmodifiable set from a variable number arguments.
static <T> Set<T>	newSet(Collection<T> c)	Creates a set that can be modified from the Collection provided.
static <T> Set<T>	newSet(T... arr)	Creates a set that can be modified from the arguments.
static <T extends Object & Comparable<? super T>> List<T>	newSortedList(Collection<? extends T> col)	Create a modifiable sorted List based on the Collection provided.
static <T> Collection<T>	nullAsEmpty(Collection<T> c)	Protects from null and returns a new instance of HashSet.
static <T> List<T>	nullAsEmpty(List<T> list)	Protects from null and returns a new instance of ArrayList if the parameter list is null .
static <T,K> Map<T,K>	nullAsEmpty(Map<T,K> map)	Protects from null and returns a new instance of HashMap if the parameter map is null.
static <T> Set<T>	nullAsEmpty(Set<T> set)	Protects from null and returns a new instance of HashSet if the parameter set is null.
static <T> Set<T>	union(Collection<T> c1, Collection<T> c2)	Returns the union of two Collections as an unmodifiable set.
static <T> Collection<T>	unique(Collection<T> c)	Use HashSet to create a unique Collection based on the one passed in.

Methods inherited from class java.lang.Object

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

Method Detail

newCaseInsensitiveSet

public static SortedSet<String> newCaseInsensitiveSet()

Creates a case-insensitive set.

Returns:

An empty case-insensitive set

isCaseInsensitiveSet

public static boolean isCaseInsensitiveSet(Set<?> set)

Returns true if the given set is a case-insensitive set.

Parameters:

set - The set. May be null.

Returns:

true if the given set is a case-insensitive set

newCaseInsensitiveMap

public static <T> SortedMap<String,T> newCaseInsensitiveMap()

Creates a case-insensitive map.

Type Parameters:

T - The object type of the map

Returns:

An empty case-insensitive map

isCaseInsensitiveMap

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

Returns true if the given map is a case-insensitive map.

Parameters:

map - The map. May be null.

Returns:

true if the given map is a case-insensitive map

nullAsEmpty

public static <T> Collection<T> nullAsEmpty(Collection<T> c)

Protects from null and returns a new instance of HashSet. if the parameter c is null.

Type Parameters:

T - the type of the collection

Parameters:

c - collection to check

Returns:

if null new HashSet otherwise the parameter that was passed in or

nullAsEmpty

public static <T,K> Map<T,K> nullAsEmpty(Map<T,K> map)

Protects from null and returns a new instance of HashMap if the parameter map is null. Otherwise return the parameter that was passed in.

nullAsEmpty

public static <T> Set<T> nullAsEmpty(Set<T> set)

Protects from null and returns a new instance of HashSet if the parameter set is null. Otherwise return the parameter that was passed in.

nullAsEmpty

public static <T> List<T> nullAsEmpty(List<T> list)

Protects from null and returns a new instance of ArrayList if the parameter list is null . Otherwise return the parameter that was passed in.

isEmpty

public static <T> boolean isEmpty(Collection<T> c)

Determine if Collection is empty or not, protects against null being passed in.

unique

public static <T> Collection<T> unique(Collection<T> c)

Use HashSet to create a unique Collection based on the one passed in. The method protects against null. The returned Collection is unmodifiable.

newReadOnlyMap

public static <T,K> Map<T,K> newReadOnlyMap(Map<T,K> map)

asReadOnlyMap

public static <T,K> Map<T,K> asReadOnlyMap(Map<T,K> map)

newReadOnlyMap

public static <T> Map<T,T> newReadOnlyMap(T[][] kv)

newMapFromLists

public static <T,K> Map<T,K> newMapFromLists(List<T> keys,
                                                         List<K> values)

Converts two List to a map. The order is important here because each key will map to one value.

newMap

public static Map<String,String> newMap(Properties properties)

newMap

public static <T,K> Map<T,K> newMap(T k0,
                                                K v0)

newMap

public static <T,K> Map<T,K> newMap(T k0,
                                                K v0,
                                                T k1,
                                                K v1)

newMap

public static <T,K> Map<T,K> newMap(T k0,
                                                K v0,
                                                T k1,
                                                K v1,
                                                T k2,
                                                K v2)

newMap

public static <T,K> Map<T,K> newMap(T k0,
                                                K v0,
                                                T k1,
                                                K v1,
                                                T k2,
                                                K v2,
                                                T k3,
                                                K v3)

newMap

public static <T,K> Map<T,K> newMap(T k0,
                                                K v0,
                                                T k1,
                                                K v1,
                                                T k2,
                                                K v2,
                                                T k3,
                                                K v3,
                                                T k4,
                                                K v4)

newMap

public static <T,K> Map<T,K> newMap(T k0,
                                                K v0,
                                                T k1,
                                                K v1,
                                                T k2,
                                                K v2,
                                                T k3,
                                                K v3,
                                                T k4,
                                                K v4,
                                                T k5,
                                                K v5)

newMap

public static <T,K> Map<T,K> newMap(T[] k,
                                                K[] v)

Builds a map from two arrays.

Parameters:

k - Array of keys.

v - Array of values.

Returns:

a map based on the two arrays.

newSet

public static <T> Set<T> newSet(Collection<T> c)

Creates a set that can be modified from the Collection provided.

newSet

@SafeVarargs
public static <T> Set<T> newSet(T... arr)

Creates a set that can be modified from the arguments.

newReadOnlySet

@SafeVarargs
public static <T> Set<T> newReadOnlySet(T... arr)

Creates an unmodifiable set from a variable number arguments.

newReadOnlySet

public static <T> Set<T> newReadOnlySet(Collection<T> c)

Creates an unmodifiable set from a Collection.

union

public static <T> Set<T> union(Collection<T> c1,
                               Collection<T> c2)

Returns the union of two Collections as an unmodifiable set.

intersection

public static <T> Set<T> intersection(Collection<T> c1,
                                      Collection<T> c2)

Returns the intersection of two Collections as an unmodifiable set.

newSortedList

public static <T extends Object & Comparable<? super T>> List<T> newSortedList(Collection<? extends T> col)

Create a modifiable sorted List based on the Collection provided.

newList

public static <T> List<T> newList(Collection<? extends T> c)

Create a modifiable list from the Collection provided. The return value is backed by an ArrayList.

newList

@SafeVarargs
public static <T> List<T> newList(T... arr)

Create a modifiable list from the arguments. The return value is backed by an ArrayList.

newReadOnlyList

public static <T> List<T> newReadOnlyList(List<? extends T> list)

Create an unmodifiable List based on the List passed in checks for null and returns an empty list if null is passed in. This one insures that the order is maintained between lists.

newReadOnlyList

@SafeVarargs
public static <T> List<T> newReadOnlyList(T... obj)

Creates an unmodifiable List from a variable number arguments.

newReadOnlyList

public static <T> List<T> newReadOnlyList(Collection<? extends T> c)

Creates an unmodifiable List from a collection.

asReadOnlyList

public static <T> List<T> asReadOnlyList(List<T> list)

Returns a read-only list. The list is backed by the original so no copy is made.

Type Parameters:

T - The type of the list

Parameters:

list - The list or null.

Returns:

A read-only proxy on the original list.

forceCompare

public static <T> int forceCompare(Object o1,
                                   Object o2)

Forces the compare of two comparable objects and removes any warnings generated by the compiler.

Returns:

Comparable the integer value of o1.compareTo(o2).

hashCode

public static int hashCode(Object o)

hashCode function that properly handles arrays, collections, maps, collections of arrays, and maps of arrays.

Parameters:

o - The object. May be null.

Returns:

the hashCode

equals

public static boolean equals(Object o1,
                             Object o2)

Equality function that properly handles arrays, lists, maps, lists of arrays, and maps of arrays.

NOTE: For Sets, this relies on the equals method of the Set to do the right thing. This is a reasonable assumption since, in order for Sets to behave properly as Sets, their values must already have a proper implementation of equals. (Or they must be specialized Sets that define a custom comparator that knows how to do the right thing). The same holds true for Map keys. Map values, on the other hand, are compared (so Map values can be arrays).

Parameters:

o1 - The first object. May be null.

o2 - The second object. May be null.

Returns:

true if the two objects are equal.