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java.lang.Objectorg.springframework.shell.support.util.CollectionUtils
public final class CollectionUtils
Miscellaneous collection utility methods. Mainly for internal use within the framework.
| Method Summary | ||
|---|---|---|
static
|
addAll(Collection<? extends T> newItems,
Collection<T> existingItems)
Adds the given items to the given collection |
|
static List<?> |
arrayToList(Object source)
Convert the supplied array into a List. |
|
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
|
filter(Iterable<? extends T> unfiltered,
Filter<T> filter)
Filters (removes elements from) the given Iterable using the
given filter. |
|
static Object |
findFirstMatch(Collection<?> source,
Collection<?> 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
|
findValueOfType(Collection<?> collection,
Class<T> type)
Find a single value of the given type in the given Collection. |
|
static
|
firstElementOf(Collection<? extends T> collection)
Returns the first element of 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 void |
mergeArrayIntoCollection(Object array,
Collection<Object> collection)
Merge the given array into the given Collection. |
|
static void |
mergePropertiesIntoMap(Properties props,
Map<String,String> map)
Merge the given Properties instance into the given Map, copying all properties (key-value pairs) over. |
|
static
|
populate(Collection<T> collection,
Collection<? extends T> items)
Populates the given collection by replacing any existing contents with the given elements, in a null-safe way. |
|
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Method Detail |
|---|
public static boolean isEmpty(Collection<?> collection)
true if the supplied Collection is null
or empty. Otherwise, return false.
collection - the Collection to check
public static boolean isEmpty(Map<?,?> map)
true if the supplied Map is null
or empty. Otherwise, return false.
map - the Map to check
public static List<?> arrayToList(Object source)
A null source value will be converted to an
empty List.
source - the (potentially primitive) array
ObjectUtils.toObjectArray(Object)
public static void mergeArrayIntoCollection(Object array,
Collection<Object> collection)
array - the array to merge (may be null)collection - the target Collection to merge the array into
public static void mergePropertiesIntoMap(Properties props,
Map<String,String> map)
Uses Properties.propertyNames() to even catch
default properties linked into the original Properties instance.
props - the Properties instance to merge (may be null)map - the target Map to merge the properties into
public static boolean contains(Iterator<?> iterator,
Object element)
iterator - the Iterator to checkelement - the element to look for
true if found, false else
public static boolean contains(Enumeration<?> enumeration,
Object element)
enumeration - the Enumeration to checkelement - the element to look for
true if found, false else
public static boolean containsInstance(Collection<?> collection,
Object element)
Enforces the given instance to be present, rather than returning
true for an equal element as well.
collection - the Collection to checkelement - the element to look for
true if found, false else
public static boolean containsAny(Collection<?> source,
Collection<?> candidates)
true if any element in 'candidates' is
contained in 'source'; otherwise returns false.
source - the source Collectioncandidates - the candidates to search for
public static Object findFirstMatch(Collection<?> source,
Collection<?> candidates)
candidates' that is contained in
'source'. If no element in 'candidates' is present in
'source' returns null. Iteration order is
Collection implementation specific.
source - the source Collectioncandidates - the candidates to search for
null if not found
public static <T> T findValueOfType(Collection<?> collection,
Class<T> type)
collection - the Collection to searchtype - the type to look for
null if none or more than one such value found
public static Object findValueOfType(Collection<?> collection,
Class<?>... types)
collection - the collection to searchtypes - the types to look for, in prioritized order
null if none or more than one such value foundpublic static boolean hasUniqueObject(Collection<?> collection)
collection - the Collection to check
true if the collection contains a single reference or
multiple references to the same instance, false else
public static <T> List<T> filter(Iterable<? extends T> unfiltered,
Filter<T> filter)
Iterable using the
given filter.
T - the type of object being filteredunfiltered - the iterable to filter; can be nullfilter - the filter to apply; can be null for none
null list
public static <T> boolean addAll(Collection<? extends T> newItems,
Collection<T> existingItems)
T - the type of item in the collection being updatednewItems - the items being added; can be null for noneexistingItems - the items being added to; must be modifiable
true if the existing collection was modified
UnsupportedOperationException - if there are items to add and the
existing collection is not modifiable
public static <T> Collection<T> populate(Collection<T> collection,
Collection<? extends T> items)
T - the type of element in the collectioncollection - the collection to populate (can be null)items - the items with which to populate the collection (can be
null or empty for none)
public static <T> T firstElementOf(Collection<? extends T> collection)
T - collection -
null if the first element is null or
the collection is null or empty
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