CollectionUtils (solo-core 1.3 API)

java.lang.Object
- cn.sexycode.util.core.collection.CollectionUtils

```
public final class CollectionUtils
extends Object
```
Various help for handling collections.

作者:

qinzaizhen

字段概要

字段
限定符和类型	字段和说明
`static Collection`	`EMPTY_COLLECTION` 已过时。 use `Collections.EMPTY_LIST` or `Collections.emptyList()` instead
`static List`	`EMPTY_LIST` 已过时。 use `Collections.EMPTY_LIST` or `Collections.emptyList()` instead
`static Map`	`EMPTY_MAP` 已过时。 use `Collections.EMPTY_MAP` or `Collections.emptyMap()` instead
`static float`	`LOAD_FACTOR`
`static int`	`MINIMUM_INITIAL_CAPACITY`

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 <T> ArrayList<T>`	`arrayList(int anticipatedSize)`
`static List`	`arrayToList(Object source)` Convert the supplied array into a List.
`static <K,V> ConcurrentHashMap<K,V>`	`concurrentMap(int expectedNumberOfElements)` Create a properly sized `ConcurrentHashMap` based on the given expected number of elements.
`static <K,V> ConcurrentHashMap<K,V>`	`concurrentMap(int expectedNumberOfElements, float loadFactor)` Create a properly sized `ConcurrentHashMap` based on the given expected number of elements and an explicit load factor
`static boolean`	`contains(Enumeration<?> enumeration, Object element)` Check whether the given Enumeration contains the given element.
`static boolean`	`contains(Iterator<?> iterator, Object element)` Check whether the given Iterator contains the given element.
`static boolean`	`containsAny(Collection<?> source, Collection<?> candidates)` Return `true` if any element in '`candidates`' is contained in '`source`'; otherwise returns `false`.
`static boolean`	`containsInstance(Collection<?> collection, Object element)` Check whether the given Collection contains the given element instance.
`static int`	`determineProperSizing(int numberOfElements)` Determine the proper initial size for a new collection in order for it to hold the given a number of elements.
`static int`	`determineProperSizing(Map original)` Given a map, determine the proper initial size for a new Map to hold the same number of values.
`static int`	`determineProperSizing(Set original)` Given a set, determine the proper initial size for a new set to hold the same number of values.
`static Class<?>`	`findCommonElementType(Collection<?> collection)` Find the common element type of the given Collection, if any.
`static <E> E`	`findFirstMatch(Collection<?> source, Collection<E> candidates)` Return the first element in '`candidates`' that is contained in '`source`'.
`static Object`	`findValueOfType(Collection<?> collection, Class<?>[] types)` Find a single value of one of the given types in the given Collection: searching the Collection for a value of the first type, then searching for a value of the second type, etc.
`static <T> T`	`findValueOfType(Collection<?> collection, Class<T> type)` Find a single value of the given type in the given Collection.
`static boolean`	`hasUniqueObject(Collection<?> collection)` Determine whether the given Collection only contains a single unique object.
`static boolean`	`isEmpty(Collection<?> collection)` Return `true` if the supplied Collection is `null` or empty.
`static boolean`	`isEmpty(Map<?,?> map)` Return `true` if the supplied Map is `null` or empty.
`static boolean`	`isEmpty(Object[] objects)`
`static boolean`	`isNotEmpty(Collection collection)`
`static boolean`	`isNotEmpty(Map map)`
`static <T> T`	`lastElement(List<T> list)` Retrieve the last element of the given List, accessing the highest index.
`static <T> T`	`lastElement(Set<T> set)` Retrieve the last element of the given Set, using `SortedSet.last()` or otherwise iterating over all elements (assuming a linked set).
`static <X,Y> Map<X,Y>`	`makeCopy(Map<X,Y> map)`
`static <T> Set<T>`	`makeCopy(Set<T> source)`
`static <K,V> Map<K,V>`	`mapOfSize(int size)` Build a properly sized map, especially handling load size and load factor to prevent immediate resizing.
`static <E> void`	`mergeArrayIntoCollection(Object array, Collection<E> collection)` Merge the given array into the given Collection.
`static <K,V> void`	`mergePropertiesIntoMap(Properties props, Map<K,V> map)` Merge the given Properties instance into the given Map, copying all properties (key-value pairs) over.
`static <A,E extends A> A[]`	`toArray(Enumeration<E> enumeration, A[] array)` Marshal the elements from the given enumeration into an array of the given type.
`static <E> Iterator<E>`	`toIterator(Enumeration<E> enumeration)` Adapt an enumeration to an iterator.

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

- 字段详细资料
  - MINIMUM_INITIAL_CAPACITY
```
public static final int MINIMUM_INITIAL_CAPACITY
```
    另请参阅:
    
    常量字段值
  - LOAD_FACTOR
```
public static final float LOAD_FACTOR
```
    另请参阅:
    
    常量字段值
  - EMPTY_LIST
```
@Deprecated
public static final List EMPTY_LIST
```
    已过时。 use Collections.EMPTY_LIST or Collections.emptyList() instead
  - EMPTY_COLLECTION
```
@Deprecated
public static final Collection EMPTY_COLLECTION
```
    已过时。 use Collections.EMPTY_LIST or Collections.emptyList() instead
  - EMPTY_MAP
```
@Deprecated
public static final Map EMPTY_MAP
```
    已过时。 use Collections.EMPTY_MAP or Collections.emptyMap() instead
- 方法详细资料
  - mapOfSize
```
public static <K,V> Map<K,V> mapOfSize(int size)
```
    Build a properly sized map, especially handling load size and load factor to prevent immediate resizing.
    Especially helpful for copy map contents.
    
    参数:
    
    size - The size to make the map.
    
    返回:
    
    The sized map.
  - determineProperSizing
```
public static int determineProperSizing(Map original)
```
    Given a map, determine the proper initial size for a new Map to hold the same number of values. Specifically we want to account for load size and load factor to prevent immediate resizing.
    
    参数:
    
    original - The original map
    
    返回:
    
    The proper size.
  - determineProperSizing
```
public static int determineProperSizing(Set original)
```
    Given a set, determine the proper initial size for a new set to hold the same number of values. Specifically we want to account for load size and load factor to prevent immediate resizing.
    
    参数:
    
    original - The original set
    
    返回:
    
    The proper size.
  - determineProperSizing
```
public static int determineProperSizing(int numberOfElements)
```
    Determine the proper initial size for a new collection in order for it to hold the given a number of elements. Specifically we want to account for load size and load factor to prevent immediate resizing.
    
    参数:
    
    numberOfElements - The number of elements to be stored.
    
    返回:
    
    The proper size.
  - concurrentMap
```
public static <K,V> ConcurrentHashMap<K,V> concurrentMap(int expectedNumberOfElements)
```
    Create a properly sized ConcurrentHashMap based on the given expected number of elements.
    
    类型参数:
    
    K - The map key type
    
    V - The map value type
    
    参数:
    
    expectedNumberOfElements - The expected number of elements for the created map
    
    返回:
    
    The created map.
  - concurrentMap
```
public static <K,V> ConcurrentHashMap<K,V> concurrentMap(int expectedNumberOfElements,
                                                         float loadFactor)
```
    Create a properly sized ConcurrentHashMap based on the given expected number of elements and an explicit load factor
    
    类型参数:
    
    K - The map key type
    
    V - The map value type
    
    参数:
    
    expectedNumberOfElements - The expected number of elements for the created map
    
    loadFactor - The collection load factor
    
    返回:
    
    The created map.
  - arrayList
```
public static <T> ArrayList<T> arrayList(int anticipatedSize)
```
  - makeCopy
```
public static <T> Set<T> makeCopy(Set<T> source)
```
  - isNotEmpty
```
public static boolean isNotEmpty(Collection collection)
```
  - isNotEmpty
```
public static boolean isNotEmpty(Map map)
```
  - isEmpty
```
public static boolean isEmpty(Object[] objects)
```
  - makeCopy
```
public static <X,Y> Map<X,Y> makeCopy(Map<X,Y> map)
```
  - isEmpty
```
public static boolean isEmpty(Collection<?> collection)
```
    Return true if the supplied Collection is null or empty. Otherwise, return false.
    
    参数:
    
    collection - the Collection to check
    
    返回:
    
    whether the given Collection is empty
  - isEmpty
```
public static boolean isEmpty(Map<?,?> map)
```
    Return true if the supplied Map is null or empty. Otherwise, return false.
    
    参数:
    
    map - the Map to check
    
    返回:
    
    whether the given Map is empty
  - arrayToList
```
public static List arrayToList(Object source)
```
    Convert the supplied array into a List. A primitive array gets converted into a List of the appropriate wrapper type.
    NOTE: Generally prefer the standard Arrays.asList(T...) method. This arrayToList method is just meant to deal with an incoming Object value that might be an Object[] or a primitive array at runtime.
    A null source value will be converted to an empty List.
    
    参数:
    
    source - the (potentially primitive) array
    
    返回:
    
    the converted List result
    
    另请参阅:
    
    ObjectUtils.toObjectArray(Object), Arrays.asList(Object[])
  - mergeArrayIntoCollection
```
public static <E> void mergeArrayIntoCollection(Object array,
                                                Collection<E> collection)
```
    Merge the given array into the given Collection.
    
    参数:
    
    array - the array to merge (may be null)
    
    collection - the target Collection to merge the array into
  - mergePropertiesIntoMap
```
public static <K,V> void mergePropertiesIntoMap(Properties props,
                                                Map<K,V> map)
```
    Merge the given Properties instance into the given Map, copying all properties (key-value pairs) over.
    Uses Properties.propertyNames() to even catch default properties linked into the original Properties instance.
    
    参数:
    
    props - the Properties instance to merge (may be null)
    
    map - the target Map to merge the properties into
  - contains
```
public static boolean contains(Iterator<?> iterator,
                               Object element)
```
    Check whether the given Iterator contains the given element.
    
    参数:
    
    iterator - the Iterator to check
    
    element - the element to look for
    
    返回:
    
    true if found, false otherwise
  - contains
```
public static boolean contains(Enumeration<?> enumeration,
                               Object element)
```
    Check whether the given Enumeration contains the given element.
    
    参数:
    
    enumeration - the Enumeration to check
    
    element - the element to look for
    
    返回:
    
    true if found, false otherwise
  - containsInstance
```
public static boolean containsInstance(Collection<?> collection,
                                       Object element)
```
    Check whether the given Collection contains the given element instance.
    Enforces the given instance to be present, rather than returning true for an equal element as well.
    
    参数:
    
    collection - the Collection to check
    
    element - the element to look for
    
    返回:
    
    true if found, false otherwise
  - containsAny
```
public static boolean containsAny(Collection<?> source,
                                  Collection<?> candidates)
```
    Return true if any element in 'candidates' is contained in 'source'; otherwise returns false.
    
    参数:
    
    source - the source Collection
    
    candidates - the candidates to search for
    
    返回:
    
    whether any of the candidates has been found
  - findFirstMatch
```
public static <E> E findFirstMatch(Collection<?> source,
                                   Collection<E> candidates)
```
    Return the first element in 'candidates' that is contained in 'source'. If no element in 'candidates' is present in 'source' returns null. Iteration order is Collection implementation specific.
    
    参数:
    
    source - the source Collection
    
    candidates - the candidates to search for
    
    返回:
    
    the first present object, or null if not found
  - findValueOfType
```
public static <T> T findValueOfType(Collection<?> collection,
                                    Class<T> type)
```
    Find a single value of the given type in the given Collection.
    
    参数:
    
    collection - the Collection to search
    
    type - the type to look for
    
    返回:
    
    a value of the given type found if there is a clear match, or null if none or more than one such value found
  - findValueOfType
```
public static Object findValueOfType(Collection<?> collection,
                                     Class<?>[] types)
```
    Find a single value of one of the given types in the given Collection: searching the Collection for a value of the first type, then searching for a value of the second type, etc.
    
    参数:
    
    collection - the collection to search
    
    types - the types to look for, in prioritized order
    
    返回:
    
    a value of one of the given types found if there is a clear match, or null if none or more than one such value found
  - hasUniqueObject
```
public static boolean hasUniqueObject(Collection<?> collection)
```
    Determine whether the given Collection only contains a single unique object.
    
    参数:
    
    collection - the Collection to check
    
    返回:
    
    true if the collection contains a single reference or multiple references to the same instance, false otherwise
  - findCommonElementType
```
public static Class<?> findCommonElementType(Collection<?> collection)
```
    Find the common element type of the given Collection, if any.
    
    参数:
    
    collection - the Collection to check
    
    返回:
    
    the common element type, or null if no clear common type has been found (or the collection was empty)
  - lastElement
```
public static <T> T lastElement(Set<T> set)
```
    Retrieve the last element of the given Set, using SortedSet.last() or otherwise iterating over all elements (assuming a linked set).
    
    参数:
    
    set - the Set to check (may be null or empty)
    
    返回:
    
    the last element, or null if none
    
    从以下版本开始:
    
    5.0.3
    
    另请参阅:
    
    SortedSet, LinkedHashMap.keySet(), LinkedHashSet
  - lastElement
```
public static <T> T lastElement(List<T> list)
```
    Retrieve the last element of the given List, accessing the highest index.
    
    参数:
    
    list - the List to check (may be null or empty)
    
    返回:
    
    the last element, or null if none
    
    从以下版本开始:
    
    5.0.3
  - toArray
```
public static <A,E extends A> A[] toArray(Enumeration<E> enumeration,
                                          A[] array)
```
    Marshal the elements from the given enumeration into an array of the given type. Enumeration elements must be assignable to the type of the given array. The array returned will be a different instance than the array given.
  - toIterator
```
public static <E> Iterator<E> toIterator(Enumeration<E> enumeration)
```
    Adapt an enumeration to an iterator.
    
    参数:
    
    enumeration - the enumeration
    
    返回:
    
    the iterator

类 CollectionUtils

字段概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

MINIMUM_INITIAL_CAPACITY

LOAD_FACTOR

EMPTY_LIST

EMPTY_COLLECTION

EMPTY_MAP

方法详细资料

mapOfSize

determineProperSizing

determineProperSizing

determineProperSizing

concurrentMap

concurrentMap

arrayList

makeCopy

isNotEmpty

isNotEmpty

isEmpty

makeCopy

isEmpty

isEmpty

arrayToList

mergeArrayIntoCollection

mergePropertiesIntoMap

contains

contains

containsInstance

containsAny

findFirstMatch

findValueOfType

findValueOfType

hasUniqueObject

findCommonElementType

lastElement

lastElement

toArray

toIterator