spring-framework / org.springframework.util / CollectionUtils

CollectionUtils

abstract class CollectionUtils

Miscellaneous collection utility methods. Mainly for internal use within the framework.

Author
Juergen Hoeller

Author
Rob Harrop

Author
Arjen Poutsma

Since
1.1.3

Constructors

<init>

CollectionUtils()

Miscellaneous collection utility methods. Mainly for internal use within the framework.

Functions

arrayToList	`open static fun arrayToList(source: Any): MutableList<Any?>` 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` 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.
contains	`open static fun contains(iterator: MutableIterator<>, element: Any): Boolean` Check whether the given Iterator contains the given element. `open static fun contains(enumeration: Enumeration<>, element: Any): Boolean` Check whether the given Enumeration contains the given element.
containsAny	`open static fun containsAny(source: MutableCollection<>, candidates: MutableCollection<>): Boolean` Return `true` if any element in '`candidates`' is contained in '`source`'; otherwise returns `false`.
containsInstance	`open static fun containsInstance(collection: MutableCollection<*>, element: Any): Boolean` 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.
findCommonElementType	`open static fun findCommonElementType(collection: MutableCollection<>): Class<>` Find the common element type of the given Collection, if any.
findFirstMatch	`open static fun <E : Any> findFirstMatch(source: MutableCollection<*>, candidates: MutableCollection<E>): E` 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.
findValueOfType	`open static fun <T : Any> findValueOfType(collection: MutableCollection<>, type: Class<T>): T` Find a single value of the given type in the given Collection. `open static fun findValueOfType(collection: MutableCollection<>, types: Array<Class<*>>): Any` 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.
hasUniqueObject	`open static fun hasUniqueObject(collection: MutableCollection<*>): Boolean` Determine whether the given Collection only contains a single unique object.
isEmpty	`open static fun isEmpty(collection: MutableCollection<>): Boolean` Return `true` if the supplied Collection is `null` or empty. Otherwise, return `false`. `open static fun isEmpty(map: MutableMap<, *>): Boolean` Return `true` if the supplied Map is `null` or empty. Otherwise, return `false`.
mergeArrayIntoCollection	`open static fun <E : Any> mergeArrayIntoCollection(array: Any, collection: MutableCollection<E>): Unit` Merge the given array into the given Collection.
mergePropertiesIntoMap	`open static fun <K : Any, V : Any> mergePropertiesIntoMap(props: Properties, map: MutableMap<K, V>): Unit` 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.
toArray	`open static fun <A : Any, E : A> toArray(enumeration: Enumeration<E>, array: Array<A>): Array<A>` 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	`open static fun <E : Any> toIterator(enumeration: Enumeration<E>): MutableIterator<E>` Adapt an enumeration to an iterator.
toMultiValueMap	`open static fun <K : Any, V : Any> toMultiValueMap(map: MutableMap<K, MutableList<V>>): MultiValueMap<K, V>` Adapt a `Map<K, List<V>>` to an `MultiValueMap<K, V>`.
unmodifiableMultiValueMap	`open static fun <K : Any, V : Any> unmodifiableMultiValueMap(map: MultiValueMap<out K, out V>): MultiValueMap<K, V>` Return an unmodifiable view of the specified multi-value map.