java.lang.Object
- com.github.aiosign.utils.CollectionUtils

```
public abstract class CollectionUtils
extends java.lang.Object
```
Miscellaneous collection utility methods. Mainly for internal use within the framework.

从以下版本开始:

1.1.3

版本:

$Id: $Id

作者:

Juergen Hoeller, Rob Harrop, Arjen Poutsma

构造器概要

构造器
构造器说明

CollectionUtils()

方法概要

所有方法静态方法具体方法
修饰符和类型	方法	说明
`static java.util.List`	`arrayToList(java.lang.Object source)`	Convert the supplied array into a List.
`static boolean`	`contains(java.util.Enumeration<?> enumeration, java.lang.Object element)`	Check whether the given Enumeration contains the given element.
`static boolean`	`contains(java.util.Iterator<?> iterator, java.lang.Object element)`	Check whether the given Iterator contains the given element.
`static boolean`	`containsAny(java.util.Collection<?> source, java.util.Collection<?> candidates)`	Return `true` if any element in '`candidates`' is contained in '`source`'; otherwise returns `false`.
`static boolean`	`containsInstance(java.util.Collection<?> collection, java.lang.Object element)`	Check whether the given Collection contains the given element instance.
`static java.lang.Class<?>`	`findCommonElementType(java.util.Collection<?> collection)`	Find the common element type of the given Collection, if any.
`static <E> E`	`findFirstMatch(java.util.Collection<?> source, java.util.Collection<E> candidates)`	Return the first element in '`candidates`' that is contained in '`source`'.
`static java.lang.Object`	`findValueOfType(java.util.Collection<?> collection, java.lang.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(java.util.Collection<?> collection, java.lang.Class<T> type)`	Find a single value of the given type in the given Collection.
`static boolean`	`hasUniqueObject(java.util.Collection<?> collection)`	Determine whether the given Collection only contains a single unique object.
`static boolean`	`isEmpty(java.util.Collection<?> collection)`	Return `true` if the supplied Collection is `null` or empty.
`static boolean`	`isEmpty(java.util.Map<?,?> map)`	Return `true` if the supplied Map is `null` or empty.
`static <T> T`	`lastElement(java.util.List<T> list)`	Retrieve the last element of the given List, accessing the highest index.
`static <T> T`	`lastElement(java.util.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 <E> void`	`mergeArrayIntoCollection(java.lang.Object array, java.util.Collection<E> collection)`	Merge the given array into the given Collection.
`static <K,V> void`	`mergePropertiesIntoMap(java.util.Properties props, java.util.Map<K,V> map)`	Merge the given Properties instance into the given Map, copying all properties (key-value pairs) over.
`static <E> java.util.Iterator<E>`	`toIterator(java.util.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

- 构造器详细资料
  - CollectionUtils
```
public CollectionUtils()
```
- 方法详细资料
  - isEmpty
```
public static boolean isEmpty(java.util.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(java.util.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 java.util.List arrayToList(java.lang.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(java.lang.Object array,
                                                java.util.Collection<E> collection)
```
    Merge the given array into the given Collection.
    
    类型参数:
    
    E - a E object.
    
    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(java.util.Properties props,
                                                      java.util.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.
    
    类型参数:
    
    K - a K object.
    
    V - a V object.
    
    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(java.util.Iterator<?> iterator,
                               java.lang.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(java.util.Enumeration<?> enumeration,
                               java.lang.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(java.util.Collection<?> collection,
                                       java.lang.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(java.util.Collection<?> source,
                                  java.util.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(java.util.Collection<?> source,
                                   java.util.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.
    
    类型参数:
    
    E - a E object.
    
    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(java.util.Collection<?> collection,
                                    java.lang.Class<T> type)
```
    Find a single value of the given type in the given Collection.
    
    类型参数:
    
    T - a T object.
    
    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 java.lang.Object findValueOfType(java.util.Collection<?> collection,
                                               java.lang.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(java.util.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 java.lang.Class<?> findCommonElementType(java.util.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(java.util.Set<T> set)
```
    Retrieve the last element of the given Set, using SortedSet.last() or otherwise iterating over all elements (assuming a linked set).
    
    类型参数:
    
    T - a T object.
    
    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(java.util.List<T> list)
```
    Retrieve the last element of the given List, accessing the highest index.
    
    类型参数:
    
    T - a T object.
    
    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
  - toIterator
```
public static <E> java.util.Iterator<E> toIterator(java.util.Enumeration<E> enumeration)
```
    Adapt an Enumeration to an Iterator.
    
    类型参数:
    
    E - a E object.
    
    参数:
    
    enumeration - the original Enumeration
    
    返回:
    
    the adapted Iterator

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

isEmpty

isEmpty

arrayToList

mergeArrayIntoCollection

mergePropertiesIntoMap

contains

contains

containsInstance

containsAny

findFirstMatch

findValueOfType

findValueOfType

hasUniqueObject

findCommonElementType

lastElement

lastElement

toIterator