CollectionUtils (crane4j-core 2.8.0 API)

java.lang.Object
- cn.crane4j.core.util.CollectionUtils

```
public class CollectionUtils
extends Object
```
Collection、Map、Iterator、Iterable utils.

作者:

huangchengxing

构造器概要

构造器
构造器和说明

CollectionUtils()

构造器
构造器和说明
`CollectionUtils()`

方法概要

所有方法静态方法具体方法
限定符和类型	方法和说明
`static Collection<?>`	`adaptObjectToCollection(Object obj)` Adapt a `Object` object to `Collection`.
`static <T,C extends Collection<T>> C`	`addAll(C collection, Collection<T> elements)`
`static <T,C extends Collection<T>> C`	`addAll(C collection, T... elements)` Add all elements to the collection.
`static <K,V> V`	`computeIfAbsent(Map<K,V> map, K key, Function<? super K,? extends V> mappingFunction)` A temporary workaround for Java 8 specific performance issue JDK-8161372 .
`static boolean`	`containsAny(Collection<?> coll1, Collection<?> coll2)` Check whether coll1 contains any element of coll2.
`static <T,C extends Collection<T>> C`	`defaultIfEmpty(C collection, C defaultCollection)` Get collection if not null, otherwise return default collection.
`static <T> T`	`get(Collection<T> collection, int index)` Get value specified index from `Collection`.
`static <T> T`	`get(Iterable<T> iterable, int index)` Get value specified index from `Iterable`.
`static <T> T`	`get(Iterator<T> iterable, int index)` Get value specified index from `Iterable`.
`static <T> T`	`getFirstNotNull(Iterable<T> iterable)` Get first not null element from the target.
`static <T> T`	`getFirstNotNull(Iterator<T> iterator)` Get first not null element from the target.
`static boolean`	`isEmpty(Collection<?> collection)` Whether the collection is empty.
`static boolean`	`isEmpty(Iterable<?> iterable)` Whether the iterable is empty.
`static boolean`	`isEmpty(Iterator<?> iterator)` Whether the iterator is empty.
`static boolean`	`isEmpty(Map<?,?> map)` Whether the map is empty.
`static boolean`	`isNotEmpty(Collection<?> collection)` Whether the collection is not empty.
`static boolean`	`isNotEmpty(Iterable<?> iterable)` Whether the iterable is not empty.
`static boolean`	`isNotEmpty(Iterator<?> iterator)` Whether the iterator is not empty.
`static boolean`	`isNotEmpty(Map<?,?> map)` Whether the map is not empty.
`static <T,C extends Collection<T>> C`	`newCollection(Supplier<C> collectionFactory, T... elements)` Create a collection from given elements.
`static <K,V> ConcurrentMap<K,V>`	`newWeakConcurrentMap()` Create a thread-safe weak reference collection.
`static boolean`	`notContainsAny(Collection<?> coll1, Collection<?> coll2)` Check whether coll1 not contains any element of coll2.
`static <K,V> Map<V,K>`	`reverse(Map<K,V> map)` Reverse given map.
`static <T> List<Collection<T>>`	`split(Collection<T> list, int size)` Split the given list into sub lists.
`static <T,C extends Collection<T>> List<C>`	`split(Collection<T> list, int size, Function<List<T>,C> mapper)` Split the given list into sub lists.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 构造器详细资料
  - CollectionUtils
```
public CollectionUtils()
```
- 方法详细资料
  - split
```
public static <T> List<Collection<T>> split(Collection<T> list,
                                            int size)
```
    Split the given list into sub lists.
    
    类型参数:
    
    T - element type
    
    参数:
    
    list - list
    
    size - size of sub list
    
    返回:
    
    sub lists
  - split
```
public static <T,C extends Collection<T>> List<C> split(Collection<T> list,
                                                        int size,
                                                        Function<List<T>,C> mapper)
```
    Split the given list into sub lists.
    
    类型参数:
    
    T - element type
    
    C - collection type
    
    参数:
    
    list - list
    
    size - size of sub list
    
    mapper - mapper to convert list to sub list
    
    返回:
    
    sub lists
  - getFirstNotNull
```
public static <T> T getFirstNotNull(Iterator<T> iterator)
```
    Get first not null element from the target.
    
    类型参数:
    
    T - element type
    
    参数:
    
    iterator - iterator
    
    返回:
    
    first not null element
  - getFirstNotNull
```
public static <T> T getFirstNotNull(Iterable<T> iterable)
```
    Get first not null element from the target.
    
    类型参数:
    
    T - element type
    
    参数:
    
    iterable - iterable
    
    返回:
    
    first not null element
  - reverse
```
public static <K,V> Map<V,K> reverse(Map<K,V> map)
```
    Reverse given map.
    
    参数:
    
    map - map to reverse
    
    返回:
    
    reversed map
  - defaultIfEmpty
```
public static <T,C extends Collection<T>> C defaultIfEmpty(C collection,
                                                           C defaultCollection)
```
    Get collection if not null, otherwise return default collection.
    
    类型参数:
    
    T - element type
    
    C - collection type
    
    参数:
    
    collection - collection
    
    defaultCollection - default collection
    
    返回:
    
    collection
  - containsAny
```
public static boolean containsAny(Collection<?> coll1,
                                  Collection<?> coll2)
```
    Check whether coll1 contains any element of coll2.
    
    参数:
    
    coll1 - coll1
    
    coll2 - coll2
    
    返回:
    
    true if coll1 contains any element of coll2, otherwise false
  - notContainsAny
```
public static boolean notContainsAny(Collection<?> coll1,
                                     Collection<?> coll2)
```
    Check whether coll1 not contains any element of coll2.
    
    参数:
    
    coll1 - coll1
    
    coll2 - coll2
    
    返回:
    
    true if coll1 not contains any element of coll2, otherwise false
  - get
```
public static <T> T get(Collection<T> collection,
                        int index)
```
    Get value specified index from Collection.
    
    类型参数:
    
    T - element type
    
    参数:
    
    collection - collection
    
    index - index, if index less than 0 or greater than or equal to collection size, return null
    
    返回:
    
    value
  - get
```
public static <T> T get(Iterable<T> iterable,
                        int index)
```
    Get value specified index from Iterable.
    
    类型参数:
    
    T - element type
    
    参数:
    
    iterable - iterable
    
    index - index
    
    返回:
    
    value
  - get
```
public static <T> T get(Iterator<T> iterable,
                        int index)
```
    Get value specified index from Iterable.
    
    类型参数:
    
    T - element type
    
    参数:
    
    iterable - iterable
    
    index - index
    
    返回:
    
    value
  - addAll
```
public static <T,C extends Collection<T>> C addAll(C collection,
                                                   T... elements)
```
    Add all elements to the collection.
    
    类型参数:
    
    T - element type
    
    C - collection type
    
    参数:
    
    collection - collection
    
    elements - elements
    
    返回:
    
    Collection itself if not null, or empty collection if null
  - addAll
```
public static <T,C extends Collection<T>> C addAll(C collection,
                                                   Collection<T> elements)
```
  - newCollection
```
@SafeVarargs
public static <T,C extends Collection<T>> C newCollection(Supplier<C> collectionFactory,
                                                                        T... elements)
```
    Create a collection from given elements.
    
    类型参数:
    
    T - element type
    
    C - collection type
    
    参数:
    
    collectionFactory - collection factory
    
    elements - elements
    
    返回:
    
    collection
  - isEmpty
```
public static boolean isEmpty(Collection<?> collection)
```
    Whether the collection is empty.
    
    参数:
    
    collection - collection
    
    返回:
    
    true if empty
  - isNotEmpty
```
public static boolean isNotEmpty(Collection<?> collection)
```
    Whether the collection is not empty.
    
    参数:
    
    collection - collection
    
    返回:
    
    true if not empty
  - isEmpty
```
public static boolean isEmpty(Map<?,?> map)
```
    Whether the map is empty.
    
    参数:
    
    map - map
    
    返回:
    
    true if empty
  - isNotEmpty
```
public static boolean isNotEmpty(Map<?,?> map)
```
    Whether the map is not empty.
    
    参数:
    
    map - collection
    
    返回:
    
    true if not empty
  - isEmpty
```
public static boolean isEmpty(Iterator<?> iterator)
```
    Whether the iterator is empty.
    
    参数:
    
    iterator - iterator
    
    返回:
    
    true if empty
  - isNotEmpty
```
public static boolean isNotEmpty(Iterator<?> iterator)
```
    Whether the iterator is not empty.
    
    参数:
    
    iterator - iterator
    
    返回:
    
    true if not empty
  - isEmpty
```
public static boolean isEmpty(Iterable<?> iterable)
```
    Whether the iterable is empty.
    
    参数:
    
    iterable - iterable
    
    返回:
    
    true if empty
  - isNotEmpty
```
public static boolean isNotEmpty(Iterable<?> iterable)
```
    Whether the iterable is not empty.
    
    参数:
    
    iterable - iterable
    
    返回:
    
    true if not empty
  - newWeakConcurrentMap
```
public static <K,V> ConcurrentMap<K,V> newWeakConcurrentMap()
```
    Create a thread-safe weak reference collection.
    
    返回:
    
    ConcurrentMap
  - adaptObjectToCollection
```
public static Collection<?> adaptObjectToCollection(Object obj)
```
    Adapt a Object object to Collection.
    
    参数:
    
    obj - obj
    
    返回:
    
    collection
  - computeIfAbsent
```
public static <K,V> V computeIfAbsent(Map<K,V> map,
                                      K key,
                                      Function<? super K,? extends V> mappingFunction)
```
    A temporary workaround for Java 8 specific performance issue JDK-8161372 .
    This class should be removed once we drop Java 8 support.
    
    类型参数:
    
    K - key type
    
    V - value type
    
    参数:
    
    map - map
    
    key - key
    
    mappingFunction - mapping function
    
    返回:
    
    value
    
    另请参阅:
    
    https://bugs.openjdk.java.net/browse/JDK-8161372

类 CollectionUtils

构造器概要

方法概要

从类继承的方法 java.lang.Object

构造器详细资料

CollectionUtils

方法详细资料

split

split

getFirstNotNull

getFirstNotNull

reverse

defaultIfEmpty

containsAny

notContainsAny

get

get

get

addAll

addAll

newCollection

isEmpty

isNotEmpty

isEmpty

isNotEmpty

isEmpty

isNotEmpty

isEmpty

isNotEmpty

newWeakConcurrentMap

adaptObjectToCollection

computeIfAbsent