Class CollectionUtils
java.lang.Object
com.igormaznitsa.jcp.utils.antpathmatcher.CollectionUtils
Miscellaneous collection utility methods. Mainly for internal use within the
framework.
- Since:
- 1.1.3
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static class
Iterator wrapping an Enumeration. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate static boolean
arrayEquals
(Object o1, Object o2) 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
Check whether the given Iterator contains the given element.static boolean
containsAny
(Collection<?> source, Collection<?> candidates) Returntrue
if any element in 'candidates
' is contained in 'source
'; otherwise returnsfalse
.static boolean
containsInstance
(Collection<?> collection, Object element) Check whether the given Collection contains the given element instance.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
static boolean
isEmpty
(Collection<?> collection) Returntrue
if the supplied Collection isnull
or empty.static boolean
Returntrue
if the supplied Map isnull
or empty.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 boolean
nullSafeEquals
(Object o1, Object o2) 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.static Object[]
toObjectArray
(Object source)
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Constructor Details
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CollectionUtils
CollectionUtils()
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Method Details
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isEmpty
Returntrue
if the supplied Collection isnull
or empty. Otherwise, returnfalse
.- Parameters:
collection
- the Collection to check- Returns:
- whether the given Collection is empty
-
isEmpty
Returntrue
if the supplied Map isnull
or empty. Otherwise, returnfalse
.- Parameters:
map
- the Map to check- Returns:
- whether the given Map is empty
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arrayToList
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. ThisarrayToList
method is just meant to deal with an incoming Object value that might be anObject[]
or a primitive array at runtime.A
null
source value will be converted to an empty List.- Parameters:
source
- the (potentially primitive) array- Returns:
- the converted List result
- See Also:
-
toObjectArray
-
mergeArrayIntoCollection
Merge the given array into the given Collection.- Parameters:
array
- the array to merge (may benull
)collection
- the target Collection to merge the array into
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mergePropertiesIntoMap
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.- Parameters:
props
- the Properties instance to merge (may benull
)map
- the target Map to merge the properties into
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contains
Check whether the given Iterator contains the given element.- Parameters:
iterator
- the Iterator to checkelement
- the element to look for- Returns:
true
if found,false
else
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nullSafeEquals
-
arrayEquals
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contains
Check whether the given Enumeration contains the given element.- Parameters:
enumeration
- the Enumeration to checkelement
- the element to look for- Returns:
true
if found,false
else
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containsInstance
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.- Parameters:
collection
- the Collection to checkelement
- the element to look for- Returns:
true
if found,false
else
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containsAny
Returntrue
if any element in 'candidates
' is contained in 'source
'; otherwise returnsfalse
.- Parameters:
source
- the source Collectioncandidates
- the candidates to search for- Returns:
- whether any of the candidates has been found
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findFirstMatch
Return the first element in 'candidates
' that is contained in 'source
'. If no element in 'candidates
' is present in 'source
' returnsnull
. Iteration order isCollection
implementation specific.- Parameters:
source
- the source Collectioncandidates
- the candidates to search for- Returns:
- the first present object, or
null
if not found
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findValueOfType
Find a single value of the given type in the given Collection.- Parameters:
collection
- the Collection to searchtype
- the type to look for- Returns:
- a value of the given type found if there is a clear match, or
null
if none or more than one such value found
-
isEmpty
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findValueOfType
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.- Parameters:
collection
- the collection to searchtypes
- the types to look for, in prioritized order- Returns:
- 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
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hasUniqueObject
Determine whether the given Collection only contains a single unique object.- Parameters:
collection
- the Collection to check- Returns:
true
if the collection contains a single reference or multiple references to the same instance,false
else
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findCommonElementType
Find the common element type of the given Collection, if any.- Parameters:
collection
- the Collection to check- Returns:
- the common element type, or
null
if no clear common type has been found (or the collection was empty)
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toArray
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
Adapt an enumeration to an iterator.- Parameters:
enumeration
- the enumeration- Returns:
- the iterator
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