Package de.xima.fc.utils

Class XCollectionUtils

java.lang.Object

de.xima.fc.utils.XCollectionUtils

public class XCollectionUtils
extends Object

Utility class for operations on collections and iterables.

Since:

7.0.0

Author:

XIMA Media GmbH

Method Summary

Modifier and Type	Method	Description
static <T> T	firstItem(List<T> list)
static <T> T	lastItem(List<T> list)
static <T> List<T>	listOfSize(int targetSize, T initialValue)
static <T> List<T>	listOfSizeWith(int targetSize, IntFunction<T> initialValue)
static <K1,K2,V> Map<K2,V>	mapKeys(Map<? extends K1,? extends V> map, Function<? super K1,? extends K2> keyMapper)	Remaps the keys of a map by applying the given mapping function to all keys, returning a new map.
static <K1,K2,V> Map<K2,V>	mapKeys(Map<? extends K1,? extends V> map, Function<? super K1,? extends K2> keyMapper, BinaryOperator<V> mergeFunction)	Remaps the keys of a map by applying the given mapping function to all keys, returning a new map.
static <K1,K2,V> Map<K2,V>	mapKeysToUnmodifiableMap(Map<? extends K1,? extends V> map, Function<? super K1,? extends K2> keyMapper)	Remaps the keys of a map by applying the given mapping function to all keys, returning a new unmodifiable map.
static <K1,K2,V> Map<K2,V>	mapKeysToUnmodifiableMap(Map<? extends K1,? extends V> map, Function<? super K1,? extends K2> keyMapper, BinaryOperator<V> mergeFunction)	Remaps the keys of a map by applying the given mapping function to all keys, returning a new unmodifiable map.
static <K1,V1,K2,V2> Map<K2,V2>	mapMap(Map<? extends K1,? extends V1> map, BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper)	Maps the entries of a map by applying the given mapping function, returning a new map.
static <K1,V1,K2,V2> Map<K2,V2>	mapMap(Map<? extends K1,? extends V1> map, BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper, BinaryOperator<V2> mergeFunction)	Maps the entries of a map by applying the given mapping function, returning a new map.
static <K1,V1,K2,V2,M extends Map<K2,V2>> M	mapMap(Map<? extends K1,? extends V1> map, BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper, BinaryOperator<V2> mergeFunction, Supplier<M> mapFactory)	Maps the entries of a map by applying the given mapping function, returning a new map.
static <K1,V1,K2,V2> Map<K2,V2>	mapToUnmodifiableMap(Map<? extends K1,? extends V1> map, BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper)	Maps the entries of a map by applying the given mapping function, returning a new unmodifiable map.
static <K1,V1,K2,V2> Map<K2,V2>	mapToUnmodifiableMap(Map<? extends K1,? extends V1> map, BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper, BinaryOperator<V2> mergeFunction)	Maps the entries of a map by applying the given mapping function, returning a new unmodifiable map.
static <K,V1,V2> Map<K,V2>	mapValues(Map<? extends K,? extends V1> map, Function<? super V1,? extends V2> valueMapper)	Remaps the values of a map by applying the given mapping function to all keys, returning a new map.
static <K,V1,V2> Map<K,V2>	mapValuesToUnmodifiableMap(Map<? extends K,? extends V1> map, Function<? super V1,? extends V2> valueMapper)	Remaps the values of a map by applying the given mapping function to all keys, returning a new unmodifiable map.
static <T> List<T>	serializableList(Iterable<T> sequence)	Takes any Collection or Iterable and converts it to a serializable list that can be transferred via the API.

Methods inherited from class java.lang.Object

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

Method Detail

firstItem

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

Type Parameters:

T - Type of the elements in the list.

Parameters:

list - List to process.

Returns:

The first item in the list, or null if the list is null or empty, or the first item is null.

lastItem

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

Type Parameters:

T - Type of the elements in the list.

Parameters:

list - List to process.

Returns:

The last item in the list, or null if the list is null or empty, or the last item is null.

listOfSize

public static <T> List<T> listOfSize(int targetSize,
                                     T initialValue)

Type Parameters:

T - Type of the list elements.

Parameters:

targetSize - Desired size of the list.

initialValue - Initial value for each element.

Returns:

A list of the given size, with each element set to the given initial value.

listOfSizeWith

public static <T> List<T> listOfSizeWith(int targetSize,
                                         IntFunction<T> initialValue)

Type Parameters:

T - Type of the list elements.

Parameters:

targetSize - Desired size of the list.

initialValue - Supplier for the initial value for each element.

Returns:

A list of the given size, with each element set to the value returned by the given supplier.

mapKeys

public static <K1,K2,V> Map<K2,V> mapKeys(Map<? extends K1,? extends V> map,
                                                            Function<? super K1,? extends K2> keyMapper)

Remaps the keys of a map by applying the given mapping function to all keys, returning a new map. If there are multiple mapped entries with the same key, the latter entry will be used.

Type Parameters:

K1 - Type of the input map keys.

K2 - Type of the output map keys.

V - Type of the map values.

Parameters:

map - Map to process.

keyMapper - Mapping function for the keys.

Returns:

The new map.

Since:

8.0.0

mapKeys

public static <K1,K2,V> Map<K2,V> mapKeys(Map<? extends K1,? extends V> map,
                                                            Function<? super K1,? extends K2> keyMapper,
                                                            BinaryOperator<V> mergeFunction)

Remaps the keys of a map by applying the given mapping function to all keys, returning a new map.

Type Parameters:

K1 - Type of the input map keys.

K2 - Type of the output map keys.

V - Type of the map values.

Parameters:

map - Map to process.

keyMapper - Mapping function for the keys.

mergeFunction - Merge function values that map to the same key.

Returns:

The new map.

Since:

8.0.0

mapKeysToUnmodifiableMap

public static <K1,K2,V> Map<K2,V> mapKeysToUnmodifiableMap(Map<? extends K1,? extends V> map,
                                                                             Function<? super K1,? extends K2> keyMapper)

Remaps the keys of a map by applying the given mapping function to all keys, returning a new unmodifiable map. If there are multiple mapped entries with the same key, the latter entry will be used.

Type Parameters:

K1 - Type of the input map keys.

K2 - Type of the output map keys.

V - Type of the map values.

Parameters:

map - Map to process.

keyMapper - Mapping function for the keys.

Returns:

The new map.

Since:

8.0.0

mapKeysToUnmodifiableMap

public static <K1,K2,V> Map<K2,V> mapKeysToUnmodifiableMap(Map<? extends K1,? extends V> map,
                                                                             Function<? super K1,? extends K2> keyMapper,
                                                                             BinaryOperator<V> mergeFunction)

Remaps the keys of a map by applying the given mapping function to all keys, returning a new unmodifiable map.

Type Parameters:

K1 - Type of the input map keys.

K2 - Type of the output map keys.

V - Type of the map values.

Parameters:

map - Map to process.

keyMapper - Mapping function for the keys.

mergeFunction - Merge function values that map to the same key.

Returns:

The new map.

Since:

8.0.0

mapMap

public static <K1,V1,K2,V2> Map<K2,V2> mapMap(Map<? extends K1,? extends V1> map,
                                                                      BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper)

Maps the entries of a map by applying the given mapping function, returning a new map. If there are multiple mapped entries with the same key, the latter entry will be used.

Type Parameters:

K1 - Type of the input map keys.

V1 - Type of the input map values.

K2 - Type of the output map keys.

V2 - Type of the output map values.

Parameters:

map - Map to process.

entryMapper - Mapping function for the entries.

Returns:

The new map.

Since:

8.0.0

mapMap

public static <K1,V1,K2,V2> Map<K2,V2> mapMap(Map<? extends K1,? extends V1> map,
                                                                      BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper,
                                                                      BinaryOperator<V2> mergeFunction)

Maps the entries of a map by applying the given mapping function, returning a new map.

Type Parameters:

K1 - Type of the input map keys.

V1 - Type of the input map values.

K2 - Type of the output map keys.

V2 - Type of the output map values.

Parameters:

map - Map to process.

entryMapper - Mapping function for the entries.

mergeFunction - Merge function for duplicate entries.

Returns:

The new map.

Since:

8.0.0

mapMap

public static <K1,V1,K2,V2,M extends Map<K2,V2>> M mapMap(Map<? extends K1,? extends V1> map,
                                                                                        BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper,
                                                                                        BinaryOperator<V2> mergeFunction,
                                                                                        Supplier<M> mapFactory)

Maps the entries of a map by applying the given mapping function, returning a new map.

Type Parameters:

K1 - Type of the input map keys.

V1 - Type of the input map values.

K2 - Type of the output map keys.

V2 - Type of the output map values.

M - Type of the returned map.

Parameters:

map - Map to process.

entryMapper - Mapping function for the entries.

mergeFunction - Merge function for duplicate entries.

mapFactory - Factory for the map to build.

Returns:

The new map.

Since:

8.0.0

mapToUnmodifiableMap

public static <K1,V1,K2,V2> Map<K2,V2> mapToUnmodifiableMap(Map<? extends K1,? extends V1> map,
                                                                                    BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper)

Maps the entries of a map by applying the given mapping function, returning a new unmodifiable map. If there are multiple mapped entries with the same key, the latter entry will be used.

Type Parameters:

K1 - Type of the input map keys.

V1 - Type of the input map values.

K2 - Type of the output map keys.

V2 - Type of the output map values.

Parameters:

map - Map to process.

entryMapper - Mapping function for the entries.

Returns:

The new map.

Since:

8.0.0

mapToUnmodifiableMap

public static <K1,V1,K2,V2> Map<K2,V2> mapToUnmodifiableMap(Map<? extends K1,? extends V1> map,
                                                                                    BiFunction<? super K1,? super V1,? extends Map.Entry<? extends K2,? extends V2>> entryMapper,
                                                                                    BinaryOperator<V2> mergeFunction)

Maps the entries of a map by applying the given mapping function, returning a new unmodifiable map.

Type Parameters:

K1 - Type of the input map keys.

V1 - Type of the input map values.

K2 - Type of the output map keys.

V2 - Type of the output map values.

Parameters:

map - Map to process.

entryMapper - Mapping function for the entries.

mergeFunction - Merge function values that map to the same key.

Returns:

The new map.

Since:

8.0.0

mapValues

public static <K,V1,V2> Map<K,V2> mapValues(Map<? extends K,? extends V1> map,
                                                              Function<? super V1,? extends V2> valueMapper)

Remaps the values of a map by applying the given mapping function to all keys, returning a new map.

Type Parameters:

K - Type of the map keys.

V1 - Type of the input map values.

V2 - Type of the output map values.

Parameters:

map - Map to process.

valueMapper - Mapping function for the values.

Returns:

The new map.

Since:

8.0.0

mapValuesToUnmodifiableMap

public static <K,V1,V2> Map<K,V2> mapValuesToUnmodifiableMap(Map<? extends K,? extends V1> map,
                                                                               Function<? super V1,? extends V2> valueMapper)

Remaps the values of a map by applying the given mapping function to all keys, returning a new unmodifiable map.

Type Parameters:

K - Type of the map keys.

V1 - Type of the input map values.

V2 - Type of the output map values.

Parameters:

map - Map to process.

valueMapper - Mapping function for the values.

Returns:

The new map.

Since:

8.0.0

serializableList

public static <T> List<T> serializableList(Iterable<T> sequence)

Takes any Collection or Iterable and converts it to a serializable list that can be transferred via the API.

Type Parameters:

T - Type of the list items.

Parameters:

sequence - A sequence of items to put into a list.

Returns:

A serializable list with the given items.