KeySetView
open class KeySetView<K : Any!, V : Any!> : MutableCollection<K>, Serializable, MutableSet<K>
A view of a ConcurrentHashMap as a Set of keys, in which additions may optionally be enabled by mapping to a common value. This class cannot be directly instantiated. See keySet(V), newKeySet(), newKeySet(int).
Summary
| Public methods |
| open Boolean |
Adds the specified key to this set view by mapping the key to the default mapped value in the backing map, if defined.
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| open Boolean |
Adds all of the elements in the specified collection to this set, as if by calling add on each one.
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| Unit |
Removes all of the elements from this view, by removing all the mappings from the map backing this view.
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| open Boolean |
Returns true if this collection contains the specified element.
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| Boolean |
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| open Boolean |
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| open Unit |
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| open ConcurrentHashMap<K, V> |
Returns the map backing this view.
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| open V? |
Returns the default mapped value for additions, or null if additions are not supported.
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| open Int |
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| Boolean |
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| open MutableIterator<K> |
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| open Boolean |
Removes the key from this map view, by removing the key (and its corresponding value) from the backing map.
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| open Boolean |
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| Boolean |
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| open Spliterator<K> |
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| Array<Any!> |
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| Array<T> |
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| String |
Returns a string representation of this collection.
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Public methods
add
open fun add(element: K): Boolean
Adds the specified key to this set view by mapping the key to the default mapped value in the backing map, if defined.
| Parameters |
e |
key to be added |
| Return |
Boolean |
true if this set changed as a result of the call |
| Exceptions |
java.lang.UnsupportedOperationException |
if no default mapped value for additions was provided |
java.lang.ClassCastException |
if the class of the specified element prevents it from being added to this set |
java.lang.NullPointerException |
if the specified key is null |
java.lang.IllegalArgumentException |
if some property of the specified element prevents it from being added to this set |
java.lang.IllegalStateException |
if the element cannot be added at this time due to insertion restrictions |
addAll
open fun addAll(elements: Collection<K>): Boolean
Adds all of the elements in the specified collection to this set, as if by calling add on each one.
| Parameters |
c |
the elements to be inserted into this set |
| Return |
Boolean |
true if this set changed as a result of the call |
| Exceptions |
java.lang.UnsupportedOperationException |
if no default mapped value for additions was provided |
java.lang.ClassCastException |
if the class of an element of the specified collection prevents it from being added to this set |
java.lang.NullPointerException |
if the collection or any of its elements are null |
java.lang.IllegalArgumentException |
if some property of an element of the specified collection prevents it from being added to this set |
java.lang.IllegalStateException |
if not all the elements can be added at this time due to insertion restrictions |
clear
fun clear(): Unit
Removes all of the elements from this view, by removing all the mappings from the map backing this view.
| Exceptions |
java.lang.UnsupportedOperationException |
if the clear method is not supported by this set |
contains
open fun contains(element: K): Boolean
Returns true if this collection contains the specified element. More formally, returns true if and only if this collection contains at least one element e such that Objects.equals(o, e).
| Parameters |
o |
element whose presence in this set is to be tested |
| Return |
Boolean |
true if this set contains the specified element |
| Exceptions |
java.lang.ClassCastException |
if the type of the specified element is incompatible with this set (optional) |
java.lang.NullPointerException |
if the specified key is null |
containsAll
fun containsAll(elements: Collection<K>): Boolean
| Parameters |
c |
collection to be checked for containment in this set |
| Return |
Boolean |
true if this set contains all of the elements of the specified collection |
| Exceptions |
java.lang.ClassCastException |
if the types of one or more elements in the specified collection are incompatible with this set (optional) |
java.lang.NullPointerException |
if the specified collection contains one or more null elements and this set does not permit null elements (optional), or if the specified collection is null |
equals
open fun equals(other: Any?): Boolean
| Parameters |
obj |
the reference object with which to compare. |
o |
object to be compared for equality with this set |
| Return |
Boolean |
true if the specified object is equal to this set |
forEach
open fun forEach(action: Consumer<in K>): Unit
| Parameters |
action |
Consumer<in K>: The action to be performed for each element |
| Exceptions |
java.lang.NullPointerException |
if the specified action is null |
getMappedValue
open fun getMappedValue(): V?
Returns the default mapped value for additions, or null if additions are not supported.
| Return |
V? |
the default mapped value for additions, or null if not supported |
hashCode
open fun hashCode(): Int
| Return |
Int |
the hash code value for this set |
isEmpty
fun isEmpty(): Boolean
| Return |
Boolean |
true if this set contains no elements |
remove
open fun remove(element: K): Boolean
Removes the key from this map view, by removing the key (and its corresponding value) from the backing map. This method does nothing if the key is not in the map.
| Parameters |
o |
the key to be removed from the backing map |
| Return |
Boolean |
true if the backing map contained the specified key |
| Exceptions |
java.lang.ClassCastException |
if the type of the specified element is incompatible with this set (optional) |
java.lang.NullPointerException |
if the specified key is null |
java.lang.UnsupportedOperationException |
if the remove operation is not supported by this set |
removeAll
open fun removeAll(elements: Collection<K>): Boolean
| Parameters |
c |
collection containing elements to be removed from this set |
| Return |
Boolean |
true if this set changed as a result of the call |
| Exceptions |
java.lang.UnsupportedOperationException |
if the removeAll operation is not supported by this set |
java.lang.ClassCastException |
if the class of an element of this set is incompatible with the specified collection (optional) |
java.lang.NullPointerException |
if this set contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null |
retainAll
fun retainAll(elements: Collection<K>): Boolean
| Parameters |
c |
collection containing elements to be retained in this set |
| Return |
Boolean |
true if this set changed as a result of the call |
| Exceptions |
java.lang.UnsupportedOperationException |
if the retainAll operation is not supported by this set |
java.lang.ClassCastException |
if the class of an element of this set is incompatible with the specified collection (optional) |
java.lang.NullPointerException |
if this set contains a null element and the specified collection does not permit null elements (optional), or if the specified collection is null |
spliterator
open fun spliterator(): Spliterator<K>
| Return |
Spliterator<K> |
a Spliterator over the elements in this set |
toArray
fun toArray(): Array<Any!>
| Return |
Array<Any!> |
an array containing all the elements in this set |
toArray
fun <T : Any!> toArray(a: Array<T>): Array<T>
| Parameters |
<T> |
the component type of the array to contain the collection |
a |
Array<T>: the array into which the elements of this set are to be stored, if it is big enough; otherwise, a new array of the same runtime type is allocated for this purpose. |
| Return |
Array<T> |
an array containing all the elements in this set |
| Exceptions |
java.lang.ArrayStoreException |
if the runtime type of the specified array is not a supertype of the runtime type of every element in this set |
java.lang.NullPointerException |
if the specified array is null |
toString
fun toString(): String
Returns a string representation of this collection. The string representation consists of the string representations of the collection's elements in the order they are returned by its iterator, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (comma and space). Elements are converted to strings as by String#valueOf(Object).
| Return |
String |
a string representation of this collection |
Properties
size
val size: Int
| Return |
Int |
the number of elements in this set (its cardinality) |
