org.jclouds.util

Class Maps2

java.lang.Object

org.jclouds.util.Maps2

public class Maps2
extends Object

General utilities used in jclouds code for Maps.

Author:

Adrian Cole

Constructor Summary

Constructors

Constructor and Description
Maps2()

Method Summary

Methods

Modifier and Type	Method and Description
static <K,V> com.google.common.base.Supplier<Map<K,V>>	composeMapSupplier(Iterable<com.google.common.base.Supplier<Map<K,V>>> suppliers)
static <K,V> Map<K,V>	convertUnsafe(com.google.common.collect.Multimap<K,V> in)
static <K,V> Map<K,V>	fromKeys(Set<K> keys, com.google.common.base.Function<? super K,V> valueFunction) Constructs a map with the given keys where values are generated by the given function.
static <K> com.google.common.base.Function<Map<K,?>,Set<K>>	keySetFunction()
static <V> Map<String,V>	renameKey(Map<String,V> in, String k1, String k2) If the supplied map contains the key k1, its value will be assigned to the key k2.
static <K1,K2,V> Map<K2,V>	transformKeys(Map<K1,V> in, com.google.common.base.Function<K1,K2> fn) change the keys but keep the values in-tact.
static <K,V> com.google.common.collect.ImmutableMap<K,V>	uniqueIndex(Iterable<? extends V> values, com.google.common.base.Function<? super V,? extends K> keyFunction) Covariant compatible version

Methods inherited from class java.lang.Object

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

Constructor Detail

Maps2

public Maps2()

Method Detail

keySetFunction

public static <K> com.google.common.base.Function<Map<K,?>,Set<K>> keySetFunction()

convertUnsafe

public static <K,V> Map<K,V> convertUnsafe(com.google.common.collect.Multimap<K,V> in)

renameKey

public static <V> Map<String,V> renameKey(Map<String,V> in,
                          String k1,
                          String k2)

If the supplied map contains the key k1, its value will be assigned to the key k2. Note that this doesn't modify the input map.

Type Parameters:

V - type of value the map holds

Parameters:

in - the map you wish to make a copy of

k1 - old key

k2 - new key

Returns:

copy of the map with the value of the key re-routed, or the original, if it k1 wasn't present.

transformKeys

public static <K1,K2,V> Map<K2,V> transformKeys(Map<K1,V> in,
                                com.google.common.base.Function<K1,K2> fn)

change the keys but keep the values in-tact.

Type Parameters:

K1 - input key type

K2 - output key type

V - value type

Parameters:

in - input map to transform

fn - how to transform the values

Returns:

immutableMap with the new keys.

composeMapSupplier

public static <K,V> com.google.common.base.Supplier<Map<K,V>> composeMapSupplier(Iterable<com.google.common.base.Supplier<Map<K,V>>> suppliers)

fromKeys

public static <K,V> Map<K,V> fromKeys(Set<K> keys,
                      com.google.common.base.Function<? super K,V> valueFunction)

Constructs a map with the given keys where values are generated by the given function. Supports duplicate and null values, but null keys are not allowed.

Type Parameters:

K - the type of the keys

V - the type of the values

Parameters:

keys - the keys to be included in the map. Keys must be non-null

valueFunction - the function that produces values for the keys

Returns:

a map containing the keys from the given set with values which are generated from the keys

See Also:

Maps.uniqueIndex(Iterable, Function)

uniqueIndex

public static <K,V> com.google.common.collect.ImmutableMap<K,V> uniqueIndex(Iterable<? extends V> values,
                                                            com.google.common.base.Function<? super V,? extends K> keyFunction)

Covariant compatible version

See Also:

Maps#uniqueIndex(Iterable, Function)}